Author name code: gibson ADS astronomy entries on 2022-09-14 author:"Gibson, Sarah E." ------------------------------------------------------------------------ Title: Synthetic Lyman-α emissions for the coronagraph aboard the ASO-S mission. I. An eruptive prominence-cavity system Authors: Zhao, J.; Zhang, P.; Gibson, S. E.; Fan, Y.; Feng, L.; Yu, F.; Li, H.; Gan, W. Q. Bibcode: 2022A&A...665A..39Z Altcode: Context. Strong ultraviolet (UV) emission from the sun will be observed by the Lyman-α Solar Telescope (LST) on board the Advanced Space-based Solar Observatory (ASO-S), scheduled for launch in 2022. It will provide continuous observations from the solar disk to the corona below a 2.5 solar radius with high resolution. To configure the appropriate observing modes and also to better understand its upcoming observations, a series of simulations and syntheses of different structures and processes need to be done in advance.
Aims: As prominence eruptions are the main drivers of space weather, the need to monitor such phenomena has been set as a priority among the objectives of ASO-S mission. In this work, we synthesize the evolution of a modeled prominence-cavity system before and during its eruption in the field of view (FOV) of LST.
Methods: We adopted the input magnetohydrodynamic (MHD) model of a prominence-cavity system, which is readily comparable to the Atmospheric Imaging Assembly (AIA) observations. The Lyman-α emission of the prominence and its eruptive counterparts are synthesized through the PRODOP code, which considers non-local thermodynamic equilibrium (NLTE) radiative transfer processes, while the other coronal part such as the cavity and surrounding streamer, are synthesized with the FORWARD package, which deals with optically thin structures.
Results: We present a discussion of the evolution of the eruptive prominence-cavity system, analyzing the synthetic emissions both on the disk near the limb and above the limb as viewed by the coronagraph, as well as the three-dimensional (3D) data of the MHD simulation.
Conclusions: The evolution of the prominence-cavity system exhibits the condensation of cavity mass onto the prominence and the evaporation of prominence plasma into the central cavity. The synthetic emission in Lyman-α shows a similar pattern as in the AIA extreme ultraviolet (EUV) wavelengths before eruption, namely, the appearance of a "horn" substructure as a precursor to the eruption. The emission of prominence with an optically thick assumption is one to two orders of magnitude lower than the optically thin one. Here, the dimming effect in Lyman-α is analyzed, for the first time, for the eruptive prominence-cavity system. Accompanying the prominence plasma motion during the eruption, the apparent dimming shows a preferred location evolving from the top and bottom of the bright core to the whole body above the bottom part, while the collisional component progressively dominates the total emission of the flux rope bright core at these locations. By analyzing the signal-to-noise ratio (S/N) with a consideration of LST's optical design, we conclude that the substructures in the cavity and the bright core of the CME can be observed with sufficient S/N at different stages in the FOV of LST. Title: Solving 3D magnetohydrostatics with RBF-FD: Applications to the solar corona Authors: Mathews, Nathaniel H.; Flyer, Natasha; Gibson, Sarah E. Bibcode: 2022JCoPh.46211214M Altcode: 2021arXiv211204561M We present a novel magnetohydrostatic numerical model that solves directly for the force-balanced magnetic field in the solar corona. This model is constructed with Radial Basis Function Finite Differences (RBF-FD), specifically 3D polyharmonic splines plus polynomials, as the core discretization. This set of PDEs is particularly difficult to solve since in the limit of the forcing going to zero it becomes ill-posed with a multitude of solutions. For the forcing equal to zero there are no numerically tractable solutions. For finite forcing, the ability to converge onto a physically viable solution is delicate as will be demonstrated. The static force-balance equations are of a hyperbolic nature, in that information of the magnetic field travels along characteristic surfaces, yet they require an elliptic type solver approach for a sparse overdetermined ill-conditioned system. As an example, we reconstruct a highly nonlinear analytic model designed to represent long-lived magnetic structures observed in the solar corona. Title: Magnetoseismology for the solar corona: from 10 Gauss to coronal magnetograms Authors: Yang, Zihao; Gibson, Sarah; He, Jiansen; Del Zanna, Giulio; Tomczyk, Steven; Morton, Richard; McIntosh, Scott; Wang, Linghua; Karak, Bidya Binay; Samanta, Tanmoy; Tian, Hui; Chen, Yajie; Bethge, Christian; Bai, Xianyong Bibcode: 2022cosp...44.2490Y Altcode: Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously magnetoseismology was mostly applied to occasionally occurring oscillation events, providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating structure. This restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter (CoMP). Using several CoMP observations of the Fe XIII 1074.7 nm and 1079.8 nm spectral lines, we obtained maps of the plasma density and wave phase speed in the corona, which allow us to map both the strength and direction of the coronal magnetic field in the plane of sky. We also examined distributions of the electron density and magnetic field strength, and compared their variations with height in the quiet Sun and active regions. Such measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere. Title: The Solaris Solar Polar MIDEX-Class Mission Concept: Revealing the Mysteries of the Sun's Poles Authors: Hassler, Donald M.; Harra, Louise K.; Gibson, Sarah; Thompson, Barbara; Gusain, Sanjay; Berghmans, David; Linker, Jon; Basu, Sarbani; Featherstone, Nicholas; Hoeksema, J. Todd; Viall, Nicholeen; Newmark, Jeffrey; Munoz-Jaramillo, Andres; Upton, Lisa A. Bibcode: 2022cosp...44.1528H Altcode: Solaris is an exciting, innovative & bold mission of discovery to reveal the mysteries of the Sun's poles. Solaris was selected for Phase A development as part of NASA's MIDEX program. Solaris builds upon the legacy of Ulysses, which flew over the solar poles, but Solaris provides an entirely new feature remote sensing, or IMAGING. Solaris will be the first mission to image the poles of the Sun from ~75 degrees latitude and provide new insight into the workings of the solar dynamo and the solar cycle, which are at the foundation of our understanding of space weather and space climate. Solaris will also provide enabling observations for improved space weather research, modeling and prediction with time series of polar magnetograms and views of the ecliptic from above, providing a unique view of the corona, coronal dynamics, and CME eruption. To reach the Sun's poles, Solaris will first travel to Jupiter, and use Jupiter's gravity to slingshot out of the ecliptic plane, and fly over the Sun's poles at ~75 degrees latitude. Just as our understanding of Jupiter & Saturn were revolutionized by polar observations from Juno and Cassini, our understanding of the Sun will be revolutionized by Solaris. Title: 4π Heliospheric Observing System - 4π-HeliOS: Exploring the Heliosphere from the Solar Interior to the Solar Wind Authors: Raouafi, Nour E.; Gibson, Sarah; Ho, George; Laming, J. Martin; Georgoulis, Manolis K.; Szabo, Adam; Vourlidas, Angelos; Mason, Glenn M.; Hoeksema, J. Todd; Velli, Marco; Berger, Thomas; Hassler, Donald M.; Kinnison, James; Viall, Nicholeen; Case, Anthony; Newmark, Jeffrey; Lepri, Susan; Krishna Jagarlamudi, Vamsee; Raouafi, Nour; Bourouaine, Sofiane; Vievering, Juliana T.; Englander, Jacob A.; Shannon, Jackson L.; Perez, Rafael M.; Chattopadhyay, Debarati; Mason, James P.; Leary, Meagan L.; Santo, Andy; Casti, Marta; Upton, Lisa A. Bibcode: 2022cosp...44.1530R Altcode: The 4$\pi$ Heliospheric Observing System (4$\pi$-HeliOS) is an innovative mission concept study for the next Solar and Space Physics Decadal Survey to fill long-standing knowledge gaps in Heliophysics. A constellation of spacecraft will provide both remote sensing and in situ observations of the Sun and heliosphere from a full 4$\pi$-steradian field of view. The concept implements a holistic observational philosophy that extends from the Sun's interior, to the photosphere, through the corona, and into the solar wind simultaneously with multiple spacecraft at multiple vantage points optimized for continual global coverage over much of a solar cycle. The mission constellation includes two spacecraft in the ecliptic and two flying as high as $\sim$70$^\circ$ solar latitude. 4$\pi$-HeliOS will provide new insights into the fundamental processes that shape the whole heliosphere. The overarching goals of the 4$\pi$-HeliOS concept are to understand the global structure and dynamics of the Sun's interior, the generation of solar magnetic fields, the origin of the solar cycle, the causes of solar activity, and the structure and dynamics of the corona as it creates the heliosphere. The mission design study is underway at the Johns Hopkins Applied Physics Laboratory Concurrent Engineering Laboratory (ACE Lab), a premier mission design center, fostering rapid and collaborative mission design evolutions. Title: Extracting characteristics of interplanetary CMEs from database of synthetic white-light images based on ensemble MHD simulations Authors: Provornikova, Elena; Gibson, Sarah; Wiltberger, Michael; Dalmasse, Kévin; Merkin, Viacheslav; Malanushenko, Anna; Vourlidas, Angelos; Arge, Charles Bibcode: 2022cosp...44.2433P Altcode: In this work, we investigate to what extent properties of CMEs determined from synthetic white light images represent properties of simulated interplanetary CMEs. The propagation of an interplanetary CME with an internal flux rope is modeled with the GAMERA global model of the inner heliosphere (0.1- 1 AU) coupled with the Gibson-Low (G&L) model of a self-similarly expanding CME with an internal magnetic field. The solar wind background in the inner heliosphere is driven by the Wang-Sheeley-Arge (WSA)-ADAPT corona solution. An ensemble of CME simulations is created by setting different input parameters of a CME flux rope in the G&L model (e.g., magnetic field topology and magnetic field strength, angular width, speed, orientation, latitude, and longitude). A set of values for each of the defining G&L parameters are taken from statistical distributions obtained from an analysis of white light CME imagery near the Sun. To set the CME magnetic structure we choose four topologies allowed by the G&L model: spheromak, tethered spheromak, flux rope, and magnetic arcade. We run an ensemble of a few hundred MHD simulations of interplanetary CMEs with internal flux rope. The ensemble is used to produce a database of synthetic CME images in white-light total brightness. We use the CACTUS package to autonomously detect CMEs in synthetic white light images and determine CME angular width and variations of CME velocity, mass, and trajectory during the interplanetary CME propagation. We then compare results from CACTUS with the ground truth data extracted directly from MHD simulation output. We analyze cases showing a disagreement between the true and inferred properties in more detail. Title: Exploring Structures and Flows with NASA's under-construction PUNCH mission Authors: DeForest, Craig; Gibson, Sarah; Thompson, Barbara; Malanushenko, Anna; Desai, Mihir; Elliott, Heather; Viall, Nicholeen; Cranmer, Steven; de Koning, Curt Bibcode: 2022cosp...44.1077D Altcode: The Polarimeter to UNify the Corona and Heliosphere is a NASA Small Explorer to image the corona and heliosphere as parts of a single system. PUNCH comprises four ~50kg smallsats, each carrying one imaging instrument, that work together to form a single "virtual coronagraph" with a 90° field of view, centered on the Sun. Scheduled for joint launch with NASA's SPHEREx mission, PUNCH starts its two-year prime science phase in 2025. PUNCH will generate full polarized image sequences of Thomson-scattered light from free electrons in the corona and young solar wind, once every four minutes continuously. This enables tracking the young solar wind and turbulent structures within it as they disconnect from the Sun itself, as well as large transients such as CMEs, CIRs, and other shocks within the young solar wind. A student-contributed X-ray spectrometer (STEAM) will address questions of coronal heating and flare physics. We present motivating science, expected advances, mission status, and how to get involved with PUNCH science now. Title: Expected results for the cradle of the Solar Wind with the Polarimeter to UNify the Corona and Heliosphere (PUNCH) Authors: DeForest, Craig; Gibson, Sarah; De Koning, Curt A.; Thompson, Barbara; Malanushenko, Anna; Desai, Mihir; Elliott, Heather; Viall, Nicholeen; Cranmer, Steven Bibcode: 2022cosp...44.1324D Altcode: The Polarimeter to UNify the Corona and Heliosphere is a NASA Small Explorer to image the corona and heliosphere as parts of a single system. Imaging the corona and heliosphere together from a constellation of four synchronized smallsats, PUNCH will — starting in 2025 — provide a unique window on global structure and cross-scale processes in the outer corona and young solar wind. PUNCH science is informed by, and complements, the results of PSP and Solar Orbiter; and will synergize with PROBA3/ASPIICS. We present early prototype results from STEREO/SECCHI and current preparation work to enable PUNCH science when data arrive, discuss anticipated results from the deeper-field, higher time resolution imaging that PUNCH will provide, and describe how to get involved with PUNCH science now. Title: Remote Sensing of Turbulence and Solar Wind Structure with the PUNCH mission Authors: DeForest, Craig; Gibson, Sarah; Matthaeus, William; Viall, Nicholeen Bibcode: 2022cosp...44.1212D Altcode: The Polarimeter to UNify the Corona and Heliosphere is a mission to observe the corona and the inner heliosphere as a unified system. PUNCH will produce continuous images of the solar wind and corona between 1.5° and 45° from the Sun, over a two year prime science mission scheduled to start in early 2025. PUNCH uses visible sunlight scattered by free electrons in the corona, to track density structures in the corona and solar wind. We will describe PUNCH's unique 3D imaging capability, mission structure, and anticipated results measuring the development of large-scale turbulence, and the large- and meso-scale structure of the solar wind itself. Title: Tracking Movement of Long-lived Equatorial Coronal Holes from Analysis of Long-term McIntosh Archive Data Authors: Harris, Jacob; Dikpati, Mausumi; Hewins, Ian M.; Gibson, Sarah E.; McIntosh, Scott W.; Chatterjee, Subhamoy; Kuchar, Thomas A. Bibcode: 2022ApJ...931...54H Altcode: Features at the Sun's surface and atmosphere are constantly changing due to its magnetic field. The McIntosh Archive provides a long-term (45 yr) record of these features, digitized from hand-drawn synoptic maps by Patrick McIntosh. Utilizing this data, we create stack plots for coronal holes, i.e., Hovmöller-type plots of latitude bands, for all longitudes, stacked in time, allowing tracking of coronal hole movement. Using a newly developed two-step method of centroid calculation, which includes a Fourier descriptor to represent a coronal hole's boundary and calculate the centroid by the use of Green's theorem, we calculate the centroids of 31 unique, long-lived equatorial coronal holes for successive Carrington rotations during the entire solar cycle 23, and estimate their slopes (time versus longitude) as the coronal holes evolve. We compute coronal hole centroid drift speeds from these slopes, and find an eastward (prograde) pattern that is actually retrograde with respect to the local differential rotation. By discussing the plausible physical mechanisms which could cause these long-lived equatorial coronal holes to drift retrograde, we identify either classical or magnetically modified westward-propagating solar Rossby waves, with a speed of a few tens to a few hundreds of meters per second, to be the best candidate for governing the drift of deep-rooted, long-lived equatorial coronal holes. To explore plausible physics of why long-lived equatorial coronal holes appear few in number during solar minimum/early rising phase more statistics are required, which will be studied in future. Title: Studying neutrinos at the LHC: FASER and its impact to the cosmic-ray physics Authors: Ariga, A.; Abreu, H.; Afik, Y.; Antel, C.; Ariga, T.; Bernlochner, F.; Boeckh, T.; Boyd, J.; Brenner, L.; Cadoux, F.; Casper, D.; Cavanagh, C.; Cerutti, F.; Chen, X.; Coccaro, A.; D'Onofrio, M.; Dozen, C.; Favre, Y.; Fellers, D.; Ferrere, D.; Gibson, S.; Gonzalez-Sevilla, S.; Gwilliam, C.; Hsu, S. C.; Hu, Z.; Iacobucci, G.; Inada, T.; Jakobsen, S.; Kajomovitz, E.; Kling, F.; Kose, U.; Kuehn, S.; Lefebvre, H.; Levinson, L.; Li, K.; Liu, J.; Magliocca, C.; McFayden, J.; Meehan, S.; Mladenov, D.; Nakamura, M.; Nakano, T.; Nessi, M.; Neuhaus, F.; Nevay, L.; Otono, H.; Pandini, C.; Pang, H.; Paolozzi, L.; Petersen, B.; Pietropaolo, F.; Prim, M. T.; Queitsch-Maitland, M.; Resnati, F.; Rokujo, H.; Salfeld-Nebgen, J.; Sato, O.; Scampoli, P.; Schmieden, K.; Schott, M.; Sfyrla, A.; Shively, S. R.; Spencer, J.; Takubo, Y.; Theiner, O.; Torrence, E.; Trojanowski, S.; Tufanli, S.; Vormwald, B.; Wang, D.; Zhan, G. Bibcode: 2022icrc.confE1025A Altcode: 2022PoS...395E1025A No abstract at ADS Title: Realizing Comprehensive 3D Observations to Probe Magnetic Energy Storage and Release in the Corona Authors: Caspi, A.; Seaton, D. B.; Casini, R.; Downs, C.; Gibson, S.; Gilbert, H.; Glesener, L.; Guidoni, S.; Hughes, J. M.; McKenzie, D.; Reeves, K.; Saint-Hilaire, P.; Shih, A. Y.; West, M. Bibcode: 2022heli.conf.4058C Altcode: Understanding impulsive energy release in the solar corona requires knowledge of the 3D coronal magnetic field and 3D signatures of energy release through systematic multi-viewpoint observations, in many wavelengths, including coronal magnetometry. Title: Scattering Polarization Diagnostic of the UV Corona Authors: Casini, R.; Gibson, S.; Newmark, J.; Fineschi, S.; Gilbert, H. Bibcode: 2022heli.conf.4053C Altcode: A largely unexplored diagnostic of the coronal magnetic field vector is offered by the linear polarization signature of the Hanle effect of far ultraviolet (FUV) resonance lines. Title: Magnetic Field Measurements in the Large Scale Solar Corona Authors: Tomczyk, S.; Gibson, S. E.; Cosmo Team Bibcode: 2022heli.conf.4031T Altcode: Daily measurements of the magnetic structure of the global solar corona are needed to advance our understanding of critical physical processes. The COSMO 1.5-m Large Coronagraph will enable coronal magnetic field observations. Title: Coronal Cavities in CoMP Observations Authors: Rumińska, Agnieszka; Ba̧k-Stȩślicka, Urszula; Gibson, Sarah E.; Fan, Yuhong Bibcode: 2022ApJ...926..146R Altcode: Quiescent coronal cavities can provide insight into solar magnetic fields. They are observed in the coronal emission lines in both polarized and unpolarized light. In the total linear polarization fraction (L/I), they often possess a "lagomorphic," or "rabbit-shaped," structure that reflects the underlying magnetic field configuration. We studied quiescent coronal cavities observed between 2012 and 2018 by the Coronal Multichannel Polarimeter (CoMP). The majority of cavities in our study had a characteristic lagomorphic structure in linear polarization. We additionally compared cavity widths as observed in intensity with sizes of their linear polarization signatures for 70 cavities and found that both features are strongly correlated. Our results indicate that chances for observing a lagomorphic structure increase greatly with cavity lifetime, suggesting that the visibility depends on the spatial orientation of the cavity. Forward-modeled observations in linear polarization of flux ropes confirmed this assumption. We conclude that observations of the solar coronal cavities in linear polarization are consistent with the theoretical model of flux rope formation and structure. Title: New Approaches to Integrated Mission, Data, and Modeling Frameworks Authors: Seaton, D. B.; Caspi, A.; Casini, R.; Downs, C.; Gibson, S.; Gilbert, H.; Glesener, L.; Guidoni, S.; Hughes, J. M.; McKenzie, D.; Reeves, K.; Saint-Hilaire, P.; Shih, A.; West, M. Bibcode: 2022heli.conf.4057S Altcode: A new generation of heliophysics missions will require integration of data from multiple missions with analysis tools and physics-based models. We discuss strategies to develop a framework for systems-integrated data and analysis environments. Title: Magnetoseismology for the solar corona: from 10 Gauss to coronal magnetograms Authors: Yang, Zihao; Bethge, Christian; Tian, Hui; Tomczyk, Steven; Morton, Richard; Del Zanna, Giulio; McIntosh, Scott; Karak, Bidya Binay; Gibson, Sarah; Samanta, Tanmoy; He, Jiansen; Chen, Yajie; Bai, Xianyong; Wang, Linghua Bibcode: 2021AGUFMSH12C..07Y Altcode: Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously magnetoseismology was mostly applied to occasionally occurring oscillation events, providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating structure. This restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter (CoMP). Using several CoMP observations of the Fe XIII 1074.7 nm and 1079.8 nm spectral lines, we obtained maps of the plasma density and wave phase speed in the corona, which allow us to map both the strength and direction of the coronal magnetic field in the plane of sky. We also examined distributions of the electron density and magnetic field strength, and compared their variations with height in the quiet Sun and active regions. Such measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere. Title: The COMPLETE mission concept for the Heliophysics Decadal Survey Authors: Seaton, Daniel; Caspi, Amir; Casini, Roberto; Downs, Cooper; Gibson, Sarah; Gilbert, Holly; Glesener, Lindsay; Guidoni, Silvina; Hughes, Marcus; Reeves, Katharine; Shih, Albert; Tomczyk, Steven; West, Matthew Bibcode: 2021AGUFMSH52A..08S Altcode: We present the COMPLETE mission concept, currently under study for the upcoming Heliophysics Decadal Survey. COMPLETE would provide the first comprehensive measurements of the 3D low-coronal magnetic field and simultaneous 3D energy release diagnostics from large eruptions (flares and CMEs) down to small-scale processes (coronal heating and solar wind outflows). COMPLETE's measurements will finally allow closure on the long-standing question of exactly how energy is stored, released, and transported in impulsive events at all scales. COMPLETE comprises an instrument suite with hard and soft X-ray spectral imagers, gamma-ray and energetic neutral atom spectral imagers, high-resolution wide-field EUV filtergram imagers, photospheric Doppler vector magnetographs, and Hanle-effect UV (Ly-a) coronal magnetographs. Distributed across three spacecraft at the L1, L4, and L5 Earth-Sun Lagrange points, the suite on each spacecraft is optimized for the measurements from that vantage point and for the mission as a whole. Data from all instruments will be processed to enable systems-level analysis from the entire observatory. COMPLETE instrument suite is deliberately complementary across its individual spacecraft, with overlapping fields of view and optimized capabilities to provide a zone of ideal coverage near the west limb as viewed from Earth. Within this region COMPLETE provides comprehensive observations of 3D structures, photospheric and coronal magnetic fields, and signatures of impulsive energy release within integrated data products. The COMPLETE mission concept, and the science and data analysis techniques it espouses, represent a strategic shift from the nearly ubiquitous current practices of siloed study in isolated subdisciplines to a comprehensive, unified systems approach to solar, coronal, and heliophysics. Title: Establishing flux rope chirality using white light polarization data from the PUNCH mission Authors: Gibson, Sarah; Morgan, Huw; Provornikova, Elena; Malanushenko, Anna; DeForest, Craig; de Koning, Curt; Fan, Yuhong; Merkin, Viacheslav; Webb, David Bibcode: 2021AGUFMSH32A..03G Altcode: Interplanetary Coronal Mass Ejections (ICMEs) are generally expected to incorporate coherently-twisted magnetic fields, i.e., magnetic flux ropes. We expect and have observed to some extent evolution and interactions between flux ropes and the background corona and solar wind, including rotation, deflection, and potentially continued topological changes. The upcoming PUNCH mission will provide a full field of view from pole to pole and fill existing gaps between coronagraphs and heliospheric imagers, and will obtain polarized brightness measurements which may be used along with brightness measurements as a powerful tool for imaging and localizing CME substructure evolution in transit. Further analysis of these substructures may then lead to information about the chirality, or handedness of magnetic twist of the flux rope. In order to demonstrate these capabilities, we present synthetic polarization from forward modeled simulations of flux rope CMEs. We compare the 3D position of substructure that can be extracted from these data to the ground truth simulation knowledge of the position of mass along the line of sight. We further consider the implications for chirality and the robustness of the method to topological variation of the flux rope at the heart of the ICME. Title: Polarimeter to UNify the Corona and Heliosphere: Mission status, activity, and science planning Authors: DeForest, Craig; Gibson, Sarah; Killough, Ronnie; Case, Traci; Beasley, Matthew; Laurent, Glenn; Colaninno, Robin Bibcode: 2021AGUFMSH35C2090D Altcode: The Polarimeter to UNify the Corona and Heliosphere (PUNCH) is an in-development mission, now in a combined Phase C/D in the NASA mission lifecycle, to image the outer solar corona and inner heliosphere as a unified system. The flight assets comprise four spacecraft to be launched to 6am/6pm Sun-synchronous Low-Earth Orbit; one spacecraft carries a Narrow Field Imager (NFI) coronagraph, and three carry copies of a Wide Field Imager (WFI) heliospheric imager. These prime instruments are specifically designed to work together as a seamless "virtual instrument" with a 90° FOV, centered on the Sun. PUNCH will produce polarized (pB) and unpolarized (B) images of the young solar wind as it forms and departs the Sun, allowing 3D analysis of solar wind and CME structure and trajectory. Aa student-contributed instrument, STEAM, comprises two solid-state X-ray spectrometers to study coronal heating and flare physics. PUNCH has an open data policy and all data products will be made available to everyone at the same time as the mission team. PUNCH is working to a launch readiness date of 3-Oct-2023. The PUNCH science team comprises PI Craig DeForest, PS Sarah Gibson, and project Co-Investigators and Associate Investigators. Organized into six working groups, we are actively preparing for the 2-year prime mission starting 90 days after launch. Science team meetings are open to all, and are announced in the usual venues and the PUNCH web page (https://punch.space.swri.edu). Current preparations include forward modeling, derivation of predicted image characteristics from existing data, and development of a suite of analysis tools in the vigorous open-source Python/NumPy/SunPy millieu. The mission is complemented by the groundbreaking PUNCH Outreach Program (POP) centered around a theme of ancient and modern sunwatching, and concentrated in the American Southwest. POP is specifically designed to support national, as well as regional, educational and outreach efforts and to stimulate interest in science by engaging under-represented populations in the focus region and around the nation. We will present the current technical status of PUNCH, the primary science objectives and observing plan, current preparation activity and working group structure, and pathways to coordinate and/or get involved with the mission. Title: Spatio-temporal Drifts of Long-lived Equatorial Coronal Holes: Do they follow the Local Differential Rotation or Rossby Waves? Authors: Harris, Jacob; Hewins, Ian; Dikpati, Mausumi; Gibson, Sarah; McIntosh, Scott; Chatterjee, Subhamoy; Kuchar, Thomas Bibcode: 2021AGUFMSH54A..09H Altcode: By developing a novel centroid-calculation technique, we analyze long-term McIntosh Archive data to compute the centroids of long-lived coronal holes (CH) in the latitude bands of +10 to -10. The technique involves a two-step algorithm for computing the CH-centroids: (i) Fast Fourier Transform to determine the surface area that represents a coronal hole in a specified latitude-band; (ii) Green's theorem to convert the surface integral to a line-integral along the hole boundary. After building a Hovmoller-type (longitude-time) diagram for these CH-centroids, we estimate their latitude-longitude drift patterns with time. We find that their spatio-temporal drift is not determined: by the local differential rotation; instead a large retrograde longitudinal speed of 100-150 m/s overpowers the local differential rotation speed, causing the resultant drift-speed of these CH-centroids in longitude with time. We reason that Rossby waves are the most plausible candidates to cause the retrograde drift patterns of these deep-rooted, long-lived equatorial coronal holes. Title: Evidence for hot plasma and current sheet formation during a coronal cavity eruption Authors: Gibson, Sarah; Bak-Steslicka, Urszula; Fan, Yuhong; Steslicki, Marek Bibcode: 2021AGUFMSH15D2055G Altcode: Solar coronal cavities are dark structures with a rarefied densitycompared with surrounding streamers. They are often observed as acomponent of the classic three-part structure of a coronal massejections (CME). Quiescent cavities are observed mostly in the polarcrown regions and may be long-lived. Some of the quiescent cavities mayfinally erupt as a CME. We present multi-wavelength observations of a previously quiescent cavityduring its eruption. We used SDO/AIA observations to determineDifferential Emission Measure (DEM) maps of this structure and studiedits kinematics. Our analysis revealed hotter plasma in the form of ringat the beginning of the eruption and hotter plasma filling the cavityduring eruption. Our results are consistent with the model of Fan 2019.We also present evidence of a current sheet during eruption. Title: Coronal Holes and High Speed Streams within the Heliosphere SC24 25 Solar Minimum Authors: Hewins, Ian; Gibson, Sarah; Emery, Barbara Bibcode: 2021AGUFMSH25C2110H Altcode: In support of the Whole Heliosphere and Planetary Interactions (WHPI) solar minimum initiative and to highlight the solar and heliospheric features at this time, we have produced solar synoptic maps of coronal hole boundaries for the extended minimum period of solar cycle 24 25 (September 2018 February 2020 or CRs 2209 2227) and two of the Parker Solar Probe times of interest CR2239 (Dec. 2020 Jan. 2021) and CR2242 (Mar. Apr. 2021). These maps are made from two positions around the sun using SDO (Solar Dynamics Observatory) and Stereo A (Solar Terrestrial Relations Observatory) EUV data. The first set of maps is made using SDO AIA 193 and 304 data showing Earths perspective. The second set of maps is made using STEREO A EUVI 195 data. The maps were made in the style established by Patrick S. McIntosh that was used to create the McIntosh Archive of synoptic maps, enabling studies of solar features and their relation to structures in the solar wind and space environment of Earth and other planets. For the SDO-based maps with Earths perspective we have traced the solar wind back to its source footpoints at or near coronal holes on the maps using the Solar Soft PFSS (Potential Field Source Surface) of M. DeRosa. We compare these results to the CCMC model runs for these Carrington rotations and OMNI solar wind data showing velocity, amplitude on the AP scale, Bz and DST. Hairy Sun PFSS models showing open and closed field lines are also included. For the Stereo-A maps we also trace solar wind back to its footpoints at or near coronal holes. We show solar wind data gathered by Stereo-A. For the rotations Mars is aligned with Stereo-A, we look at Maven solar wind data. In both of these cases, we correlate fluctuations of solar wind data with specific coronal holes in the maps. All of this data will be organized into a mosaic of coronal hole and solar wind data. Together, these data provide a comprehensive study of the organization of coronal holes and high speed solar wind streams for each Carrington Rotation during the solar minimum period as well as some Parker Solar Probe post minimum Carrington Rotations of interest. Title: Understanding Solar Eruptions, Solar Wind Formation, and how the Sun Connects to the Heliosphere through a Polar Perspective Authors: Viall, Nicholeen; Gibson, Sarah; Hassler, Don; Newmark, Jeffrey; Seaton, Daniel; Downs, Cooper Bibcode: 2021AGUFMSH34D..01V Altcode: A major limitation to our understanding of how the Sun connects to the heliosphere is due to our ecliptic bias: all remote observations of the Sun and corona have been made from the ecliptic. The ecliptic viewpoint by itself can never capture the global corona and its connection to the heliosphere. The ecliptic view has large uncertainties in measurements of the polar magnetic fields and has limited ability to measure longitudinal coronal structure. A polar perspective can provide new ways to test theories of a host of solar and heliospheric physics problems, from the quiescent processes involved in solar wind formation, up through transient solar eruptions and coronal mass ejections (CMEs). Because the structure and strength of the polar photospheric magnetic fields shape the corona and provide key input to coronal and heliospheric models, measuring and tracking the evolution of the polar magnetic fields provides the bones of the corona-heliosphere connection as well as information on the storage and release of explosive energy. Images of the corona in EUV and white light provide the coronal counterpart to the photospheric magnetic field measurements for connecting the Sun to the heliosphere. They capture global coronal connectivity and interactions, longitudinal expansion and structure, and the effects of co-rotation. Since CMEs tend to deflect toward the equator, a polar view captures essentially all Earth-and planet-directed CMEs from a view perpendicular to their direction of propagation. Overall, the discovery space for a polar imager is enormous. We describe progress on these topics that can be expected with Solar Orbiter, which will get to 30 degrees orbital inclination in the extended mission. We also discuss the unique science that can be done by continuous imaging of the polar magnetic fields and corona from above 70 degrees for at least a solar rotation, such as proposed by the Solaris mission. Title: Understanding the coronal origins of global heliospheric phenomena through 3D measurements with COMPLETE Authors: Caspi, Amir; Seaton, Daniel; Casini, Roberto; Downs, Cooper; Gibson, Sarah; Gilbert, Holly; Glesener, Lindsay; Guidoni, Silvina; Hughes, Marcus; Reeves, Katharine; Shih, Albert; Tomczyk, Steven; West, Matthew Bibcode: 2021AGUFMSH25F2151C Altcode: Impulsive solar eruptions (flares, coronal mass ejections) and more gradual energetic processes (coronal heating in active regions, solar wind outflows) are powered and governed by the Sun's complex coronal magnetic field. The evolution of these events in the low and middle corona has direct impact on global scales throughout the corona and heliosphere, including as drivers of space weather that affect human and technological assets, but a coherent understanding of globally connected behavior necessarily requires understanding its origins at the Sun. Despite many decades of research, it is still poorly understood exactly how magnetic energy is stored and impulsively released to power plasma heating, particle acceleration, and bulk flows. Breakthroughs have been hindered by two critical limitations: lack of knowledge of the 3D coronal magnetic field and its evolution, and a similar lack of insight into how localized energy release manifests and propagates within 3D coronal structures. Transformative progress to close these gaps requires systematic observations from multiple viewpoints, in a variety of wavelengths, and including coronal magnetometry. Recent and ongoing technological advancements allow us to realize these goals within a decadal timescale. To that end, we present the COMPLETE mission concept, currently under study for the upcoming Heliophysics Decadal Survey. COMPLETEs highly co-optimized and complementary instrument suite include spectroscopic imagers for X-rays, gamma-rays, and energetic neutral atoms; high-resolution wide-field EUV filtergram imagers; photospheric Doppler vector mangetographs; and Hanle-effect UV (Lyman-alpha) coronal magnetographs. Distributed across three spacecraft at the L1, L4, and L5 Earth-Sun Lagrange points, COMPLETE would provide the first comprehensive measurements of the 3D low- and middle-coronal magnetic field and simultaneous 3D energy-release diagnostics from large eruptions down to small-scale processes. COMPLETE represents a strategic shift towards a comprehensive, unified systems approach to solar, coronal, and heliospheric physics, to enable us to finally close decades-old questions of how the Suns magnetic field and impulsive energy release are interrelated, from local to global scales. Title: Preferred Longitudes and Other Characteristics of Polar Coronal Hole Extensions over Five Solar Cycles Authors: Emery, Barbara; Hewins, Ian; Gibson, Sarah; Kuchar, Thomas; Webb, David; McFadden, Robert Bibcode: 2021AGUFMSH55D1879E Altcode: The McIntosh archive covers coronal holes (CHs) from Skylab in 1973 in Solar Cycle (SC) 20 to Carrington Rotation (CR) 2186 in the solar minimum of 2009 between SC23-24. We also have CH boundaries in solar synoptic maps from September 2018 to February 2020 (CR2209-2227) as part of the Whole Heliosphere and Planetary Interactions (WHPI) project in the solar minimum between SC24-25. Polar CHs are found in most parts of the solar cycle, except for solar maximum, often with low latitude extensions. We examine the characteristics of polar CH extensions as a function of hemisphere to document their number, their latitudinal extent, and determine any preferred longitudes. Other studies have found preferred longitudes of clusters of long-lived CHs, and especially of active regions, where active regions are often anti-correlated with the equatorial extensions of polar CHs. We anticipate changes in the characteristics of polar CH extensions over four or five solar cycles, and we examine also their relationship to other low-latitude long-lived CHs, and to active regions. Title: Early Results from Whole Heliosphere Planetary Interactions (WHPI) Campaigns Authors: Thompson, Barbara; Allen, Robert; de Toma, Giuliana; Gibson, Sarah; Qian, Liying Bibcode: 2021AGUFMSH11A..03T Altcode: The Whole Heliosphere and Planetary Interactions (WHPI) is an international initiative focused around the solar minimum period that aims to understand the interconnected sun-heliospheric-planetary system, by facilitating and encouraging interdisciplinary activities. Particular WHPI science foci include the global connected structure of the heliosphere and planetary space environments/atmospheres, the origins and impacts of high-speed solar wind streams, CMEs from sun-to-heliopause, and comparative solar minima. This is achieved through a series of coordinated observing campaigns, including Parker Solar Probe perihelia, and virtual interactions including a dedicated workshop where observers and modelers get together to discuss, compare, and combine research results. We present a summary of the outcomes and activities of the WHPI science workshop held September 13-17, 2021, and an update on the repository of data (observations and models, Sun to solar wind to planets) that have been gathered. Title: The COronal Magnetism Observatory (COMO) Authors: Casini, Roberto; Newmark, Jeffrey; Fineschi, Silvano; Burkepile, Joan; Gibson, Sarah; Gilbert, Holly; Raouafi, Nour Bibcode: 2021AGUFMSH15G2092C Altcode: Structuring of solar coronal plasma by the magnetic field is the key to understanding the fundamental physical processes of energy dissipation in the corona. The coronal magnetic field is crucial to understanding coronal dynamics and space weather. We present the COronal Magnetism Observatory (COMO), a new polarimetric imaging solar coronagraph for the FUV (H Ly-alpha), to be deployed to the International Space Station. COMO will provide the first global maps of the magnetic field and solar wind properties from 1.1 to 3 Rsun.The instrument will measure the linearly polarized scattered light from the low through the middle corona with a spatial sampling of 2.8 arcsec/pixel. The science mission relies on a variety of different polarization diagnostic methods (unsaturated Hanle effect, Doppler dimming) to infer information on the magnetic state of the active low corona, and the solar wind velocity/acceleration in the middle corona. The instrument design is an adaptation of the internally occulted coronagraph for the Sounding-rocket Coronagraphic Experiment (SCORE), successfully flown in 2009 as part of the NASA HERSCHEL experiment, and the dual-beam polarimeter adopts a newly developed, highly stable, Al-MgF2 multilayer coating for the polarization analyzer. Title: A 3D Mesh-Free Solver for Magnetohydrostatic Simulations in the Corona Authors: Mathews, Nathaniel; Flyer, Natasha; Gibson, Sarah Bibcode: 2021AGUFMSH15G2084M Altcode: An understanding of coronal magnetism is vital to heliophysics, but typical methods to model such fields are not robust to the true complexities present in the Sun. We present a first-of-its-kind forced magnetohydrostatic numerical solver for the purpose of reconstructing coronal magnetic fields. This solver is constructed with Radial Basis Function finite differences as the core discretization, in a novel application of that method. This discretization allows the solver to use scattered datasets. We perform accurate reconstruction of a highly nonlinear analytic flux rope model, and investigate an application of the solver to the coronal magnetic field inverse problem. Title: The Solaris Solar Polar MIDEX Mission Concept: Revealing the Mysteries of the Sun's Poles Authors: Hassler, Don; Gibson, Sarah; Newmark, Jeffrey Bibcode: 2021AGUFMSH34D..07H Altcode: Solaris is an exciting, innovative & bold mission of discovery to reveal the mysteries of the Suns poles. Solaris was selected for Phase A development as part of NASA's MIDEX program. Solaris builds upon the legacy of Ulysses, which flew over the solar poles, but Solaris provides an entirely new featureremote sensing, or IMAGING. Solaris will be the first mission to image the poles of the Sun from ~75 degrees latitude and provide new insight into the workings of the solar dynamo and the solar cycle, which are at the foundation of our understanding of space weather and space climate. Solaris will also provide enabling observations for improved space weather research, modeling and prediction with time series of polar magnetograms and views of the ecliptic from above, providing a unique view of the corona, coronal dynamics, and CME eruption. To reach the Suns poles, Solaris will first travel to Jupiter, and use Jupiters gravity to slingshot out of the ecliptic plane, and fly over the Suns poles at ~75 degrees latitude. Just as our understanding of Jupiter & Saturn were revolutionized by polar observations from Juno and Cassini, our understanding of the Sun will be revolutionized by Solaris. Title: Large ensemble simulations of CMEs in the inner heliosphere: toward constraining distributions of CME parameters near the Sun Authors: Provornikova, Elena; Merkin, Viacheslav; Malanushenko, Anna; Gibson, Sarah; Vourlidas, Angelos; Arge, Charles; Dalmasse, Kevin Bibcode: 2021AGUFMSH32A..01P Altcode: In this work, we take a comprehensive approach which combines physics-based simulations, observations and statistical methods toward understanding the evolution of coronal mass ejections in the inner heliosphere and linking characteristics of CMEs near the Sun and their plasma and magnetic field properties as they would be observed at 1 AU. We simulate the propagation of ICMEs using a global model of the inner heliosphere driven at the coronal boundary by the Wang-Sheeley-Arge (WSA)-ADAPT model. ICMEs are initiated at 21.5 solar radii using an MHD analytical Gibson-Low (G&L) model of a self-similarly expanding magnetic bubble with defining parameters (e.g., latitude and longitude, magnetic field topology and strength, angular width, speed, orientation). The ICME propagation is simulated using the inner heliosphere version of the Grid Agnostic MHD for Extended Research Applications (GAMERA) MHD model, which is a reinvention of the high-heritage Lyon-Fedder-Mobarry (LFM) code. A set of values for each of the defining G&L parameters was constrained by the statistical representation of CME images near the Sun. Intending to span the solar cycle, we model ICME propagation in different solar wind backgrounds corresponding to rising, declining, and minimum solar cycle phases. A grid of CME parameters and three solar wind backgrounds constitute a parameter space for 50,000 ICME simulations. We describe types and a structure of the output data from simulations and an algorithm of automatic performance of many thousands of runs. We discuss methods to incorporate CME data from both solar observations and in-situ at 1 AU in a statistical study to construct posterior predictive distributions of CME model input parameters. Title: Latitude Variations in Primary and Secondary Polar Crown Polarity Inversion Lines and Polar Coronal Hole Boundaries over Five Solar Cycles Authors: Emery, B. A.; Webb, D. F.; Gibson, S. E.; Hewins, I. M.; McFadden, R. H.; Kuchar, T. A. Bibcode: 2021SoPh..296..119E Altcode: We undertake a five solar-cycle (SC 19 - 23) ≈55-year (December 1954 to August 2009) study of the high latitude polarity inversion lines (PILs) using the recently digitized McIntosh Archive (McA) of solar synoptic (Carrington) maps. We looked at the evolution of the median solar latitudes of primary and secondary PILs, and of the polar coronal hole (CH) boundary for all 732 Carrington Rotations (CRs). We found hemispheric differences in the "Rush to the Poles" (RttP) where the polar CH gaps are often longer in the southern hemisphere (SH), and the secondary PIL reaches its polemost latitude at the end of its RttP later and more poleward than in the northern hemisphere (NH). The latitude oscillations found after this poleward peak are also stronger and often longer in the SH than in the NH, and exhibit a 22-year variation. The location variations in the CH boundaries and PILs appear to be at least partly associated with similar variations in the magnetic field. We also found equatorward expansions of the polar CHs by ≈50% and equatorward shifts in the PILs that were part of a disturbance that propagated ≈15°/CR from the SH to the NH in the descending phase of SC 23. Title: STRIA: A new module within FORWARD towards modelling PUNCH datasets Authors: Gilly, C. R.; Cranmer, S.; Gibson, S. Bibcode: 2021AAS...23832802G Altcode: A new module is being written within the FORWARD toolkit in SSW which will help us to interpret future observations from the PUNCH mission (a new heliosphere imager being launched in 2023). This presentation will consist of preliminary results from this project. The next step past this striated model (STRIA) will involve placing radially outflowing blobs of plasma into the model and discerning expected detection challenges/limits. Title: Identifying Non-potential Energy Hot Spots In A Global Coronal Simulation Authors: Corchado Albelo, M. F.; Gibson, S. E.; Linker, J.; Mackay, D. H.; Dalmasse, K.; Malanushenko, A. Bibcode: 2021AAS...23832803C Altcode: Observing the global coronal magnetic field remains a difficult task; limiting our understanding of the evolution of global phenomena in these external layers of the solar atmosphere. Therefore, we rely on models to get the solar exterior global field. While models can extrapolate the magnetic field from surface flux and vector magnetogram observations, e.g. by assuming a current-free corona, other techniques are used to simulate the current-carrying field via magnetohydrodynamic (MHD) evolution or surface flux transport of large scale field, and inserting current-carrying small scale field structures like twisted flux ropes into the corona. These current-carrying fields are of interest for studying solar energetic eruptions like coronal mass ejections and flares because they provide the energy reservoir needed to drive these events. Previous studies suggest that ground-based infrared polarimetric measurements of Fe XIII (1074.7 nm) line correlate with the energy of the current-carrying field. In this study we generated synthetic polarimetric observations from a fully-resolved magnetohydrodynamics model of the August 21, 2017 eclipse. The synthetic observations were used as input to a diagnostic we developed to identify regions where the modeling team inserted twisted flux ropes. The diagnostic evaluated linearly and circularly polarized synthetic observations of the corona as a means to identify the current-carrying magnetic energy density. We found that the diagnostic does identify the distribution of flux ropes in the corona. Thus, our findings motivate the implementation of polarimetric measurements to identify "hot spots" in which we can insert flux ropes and a degree of the twist/shear in the current-carrying field. Title: Polarimeter to UNify the Corona and Heliosphere: Science Summary and Mission Status Authors: Deforest, C.; Gibson, S.; Killough, R.; Beasley, M.; Laurent, G.; Colaninno, R.; The Punch Team Bibcode: 2021AAS...23831304D Altcode: The Polarimeter to UNify the Corona and Heliosphere (PUNCH) is a constellation mission being built within NASA's Small Explorer program. During its two year nominal mission, PUNCH will use a constellation of four spacecraft as a single visible-light "virtual coronagraph" with a 90° outer field of view and a 1.25° inner field of view, to continuously produce global, photometric, 3D images of the outer reaches of the solar corona and the solar wind itself. PUNCH uses polarization properties of Thomson scattering to extract 3D information along its single line of sight from near Earth.

The PUNCH science objectives are to understand both (1) how coronal structures become the ambient solar wind, and (2) the dynamic evolution of transient structures within the solar wind. Subtopics include mapping the evolving flow of the solar wind, identifying microstructures and turbulence in the young solar wind, locating the Alfvén surface and other natural boundaries of the corona-heliosphere system, tracking CMEs and their evolution in 3D, measuring the formation of solar wind co-rotating interaction regions, and determining the large-scale dynamics of interplanetary shocks. These are addressed through deep-field 3D imaging, using the polarization properties of Thomson-scattered light.

PUNCH is finishing up its Phase B (preliminary design), with KDP-C expected in 2021 July and a Launch Readiness Date in late 2023.

This poster summarizes the science objectives, novel approach, and current status of the mission. Title: The Solaris Solar Polar MIDEX Mission Concept: Revealing the Mysteries of the Sun's Poles Authors: Hassler, D. M.; Newmark, J.; Gibson, S. Bibcode: 2021AAS...23831316H Altcode: Solaris is an exciting, innovative & bold mission of discovery to reveal the mysteries of the Sun's poles. Solaris was selected for Phase A development as part of NASA's MIDEX program. Solaris builds upon the legacy of Ulysses, which flew over the solar poles, but Solaris provides an entirely new feature⋯remote sensing, or IMAGING.

Solaris will be the first mission to image the poles of the Sun from ~75 degrees latitude and provide new insight into the workings of the solar dynamo and the solar cycle, which are at the foundation of our understanding of space weather and space climate. Solaris will also provide enabling observations for improved space weather research, modeling and prediction with time series of polar magnetograms and views of the ecliptic from above, providing a unique view of the corona, coronal dynamics, and CME eruption.

To reach the Sun's poles, Solaris will first travel to Jupiter, and use Jupiter's gravity to slingshot out of the ecliptic plane, and fly over the Sun's poles at ~75 degrees latitude. Just as our understanding of Jupiter & Saturn were revolutionized by polar observations from Juno and Cassini, our understanding of the Sun will be revolutionized by Solaris. Title: Simulating the Solar Minimum Corona in UV Wavelengths with Forward Modeling II. Doppler Dimming and Microscopic Anisotropy Effect Authors: Zhao, Jie; Gibson, Sarah E.; Fineschi, Silvano; Susino, Roberto; Casini, Roberto; Cranmer, Steven R.; Ofman, Leon; Li, Hui Bibcode: 2021ApJ...912..141Z Altcode: In ultraviolet (UV) spectropolarimetric observations of the solar corona, the existence of a magnetic field, solar wind velocity, and temperature anisotropies modify the linear polarization associated with resonant scattering. Unlike previous empirical models or global models, which present blended results of the above physical effects, in this work, we forward-model expected signals in the H I Lyα line (121.6 nm) by adopting an analytic model that can be adjusted to test the roles of different effects separately. We find that the impact of all three effects is most evident in the rotation of the linear polarization direction. In particular, (1) for magnetic fields between ∼10 and ∼100 G, the Hanle effect modifies the linear polarization at low coronal heights, rotating the linear polarization direction clockwise (counterclockwise) when the angle between the magnetic field and the local vertical is greater (less) than the van Vleck angle, which is consistent with the result of Zhao et al.; (2) solar wind velocity, which increases with height, has a significant effect through the Doppler dimming effect at higher coronal heights, rotating the linear polarization direction in an opposite fashion to the Hanle effect; and (3) kinetic temperature anisotropies are most significant at lower heights in open nonradial magnetic field regions, producing tilt opposite to isotropic Doppler dimming. The fact that the three effects operate differently in distinct spatial regimes opens up the possibility for using linear polarization measurements in UV lines to diagnose these important physical characteristics of the solar corona. Title: Magnetofrictional Modeling of an Erupting Pseudostreamer Authors: Karna, Nishu; Savcheva, Antonia; Gibson, Sarah; Tassev, Svetlin; Reeves, Katharine K.; DeLuca, Edward E.; Dalmasse, Kévin Bibcode: 2021ApJ...913...47K Altcode: In this study, we present the magnetic configuration of an erupting pseudostreamer observed on 2015 April 19, on the southwest limb of the Sun, with a prominence cavity embedded inside. The eruption resulted in a partial halo coronal mass ejection. The prominence eruption begins with a slow rise and then evolves to a fast-rise phase. We analyze this erupting pseudostreamer using the flux-rope insertion method and magnetofrictional relaxation to establish a sequence of plausible out-of-equilibrium magnetic configurations. This approach allows the direct incorporation of observations of structures seen in the corona (filament and cavity) to appropriately model the pseudostreamer based on SDO/HMI line-of-sight photospheric magnetograms. We also perform a topological analysis in order to determine the location of quasiseparatrix layers (QSLs) in the models, producing Q-maps to examine how the QSL locations progress in the higher iterations. We found that the axial flux in our best-fit unstable model was a factor of 20 times higher than we found in our marginally stable case. We computed the average magnetic field strength of the prominence and found that the unstable model exhibits twice the average field strength of the stable model. The eruption height from our modeling matches very well with the prominence eruption height measured from the AIA observation. The Q-maps derived from the model reproduce structures observed in LASCO/C2. Thus, the modeling and topological analysis results are fully consistent with the observed morphological features, implying that we have captured the large magnetic structure of the erupting filament in our magnetofrictional simulation. Title: Inward-propagating Plasma Parcels in the Solar Corona: Models with Aerodynamic Drag, Ablation, and Snowplow Accretion Authors: Cranmer, Steven R.; DeForest, Craig E.; Gibson, Sarah E. Bibcode: 2021ApJ...913....4C Altcode: 2021arXiv210312039C Although the solar wind flows primarily outward from the Sun to interplanetary space, there are times when small-scale plasma inflows are observed. Inward-propagating density fluctuations in polar coronal holes were detected by the COR2 coronagraph on board the STEREO-A spacecraft at heliocentric distances of 7-12 solar radii, and these fluctuations appear to undergo substantial deceleration as they move closer to the Sun. Models of linear magnetohydrodynamic waves have not been able to explain these deceleration patterns, so they have been interpreted more recently as jets from coronal sites of magnetic reconnection. In this paper, we develop a range of dynamical models of discrete plasma parcels with the goal of better understanding the observed deceleration trend. We found that parcels with a constant mass do not behave like the observed flows, and neither do parcels undergoing ablative mass loss. However, parcels that accrete mass in a snowplow-like fashion can become decelerated as observed. We also extrapolated OMNI in situ data down to the so-called Alfvén surface and found that the initial launch point for the observed parcels may often be above this critical radius. In other words, in order for the parcels to flow back down to the Sun, their initial speeds are probably somewhat nonlinear (i.e., supra-Alfvénic), and thus the parcels may be associated with structures such as shocks, jets, or shear instabilities. Title: Mapping the global magnetic field in the solar corona through magnetoseismology Authors: Yang, Zihao; Bethge, Christian; Tian, Hui; Tomczyk, Steven; Morton, Richard; Del Zanna, Giulio; McIntosh, Scott; Karak, Bidya Binay; Gibson, Sarah; Samanta, Tanmoy; He, Jiansen; Chen, Yajie; Wang, Linghua; Bai, Xianyong Bibcode: 2021EGUGA..23..642Y Altcode: Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously magnetoseismology was mostly applied to occasionally occurring oscillation events, providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating structure. This restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter (CoMP). Using several CoMP observations of the Fe XIII 1074.7 nm and 1079.8 nm spectral lines, we obtained maps of the plasma density and wave phase speed in the corona, which allow us to map both the strength and direction of the coronal magnetic field in the plane of sky. We also examined distributions of the electron density and magnetic field strength, and compared their variations with height in the quiet Sun and active regions. Such measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere. Title: Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST) Authors: Rast, Mark P.; Bello González, Nazaret; Bellot Rubio, Luis; Cao, Wenda; Cauzzi, Gianna; Deluca, Edward; de Pontieu, Bart; Fletcher, Lyndsay; Gibson, Sarah E.; Judge, Philip G.; Katsukawa, Yukio; Kazachenko, Maria D.; Khomenko, Elena; Landi, Enrico; Martínez Pillet, Valentín; Petrie, Gordon J. D.; Qiu, Jiong; Rachmeler, Laurel A.; Rempel, Matthias; Schmidt, Wolfgang; Scullion, Eamon; Sun, Xudong; Welsch, Brian T.; Andretta, Vincenzo; Antolin, Patrick; Ayres, Thomas R.; Balasubramaniam, K. S.; Ballai, Istvan; Berger, Thomas E.; Bradshaw, Stephen J.; Campbell, Ryan J.; Carlsson, Mats; Casini, Roberto; Centeno, Rebecca; Cranmer, Steven R.; Criscuoli, Serena; Deforest, Craig; Deng, Yuanyong; Erdélyi, Robertus; Fedun, Viktor; Fischer, Catherine E.; González Manrique, Sergio J.; Hahn, Michael; Harra, Louise; Henriques, Vasco M. J.; Hurlburt, Neal E.; Jaeggli, Sarah; Jafarzadeh, Shahin; Jain, Rekha; Jefferies, Stuart M.; Keys, Peter H.; Kowalski, Adam F.; Kuckein, Christoph; Kuhn, Jeffrey R.; Kuridze, David; Liu, Jiajia; Liu, Wei; Longcope, Dana; Mathioudakis, Mihalis; McAteer, R. T. James; McIntosh, Scott W.; McKenzie, David E.; Miralles, Mari Paz; Morton, Richard J.; Muglach, Karin; Nelson, Chris J.; Panesar, Navdeep K.; Parenti, Susanna; Parnell, Clare E.; Poduval, Bala; Reardon, Kevin P.; Reep, Jeffrey W.; Schad, Thomas A.; Schmit, Donald; Sharma, Rahul; Socas-Navarro, Hector; Srivastava, Abhishek K.; Sterling, Alphonse C.; Suematsu, Yoshinori; Tarr, Lucas A.; Tiwari, Sanjiv; Tritschler, Alexandra; Verth, Gary; Vourlidas, Angelos; Wang, Haimin; Wang, Yi-Ming; NSO and DKIST Project; DKIST Instrument Scientists; DKIST Science Working Group; DKIST Critical Science Plan Community Bibcode: 2021SoPh..296...70R Altcode: 2020arXiv200808203R The National Science Foundation's Daniel K. Inouye Solar Telescope (DKIST) will revolutionize our ability to measure, understand, and model the basic physical processes that control the structure and dynamics of the Sun and its atmosphere. The first-light DKIST images, released publicly on 29 January 2020, only hint at the extraordinary capabilities that will accompany full commissioning of the five facility instruments. With this Critical Science Plan (CSP) we attempt to anticipate some of what those capabilities will enable, providing a snapshot of some of the scientific pursuits that the DKIST hopes to engage as start-of-operations nears. The work builds on the combined contributions of the DKIST Science Working Group (SWG) and CSP Community members, who generously shared their experiences, plans, knowledge, and dreams. Discussion is primarily focused on those issues to which DKIST will uniquely contribute. Title: Gibson & Low Flux Rope Model: More Than a Spheromak! Authors: Malanushenko, Anna; Gibson, Sarah; Provornikova, Elena; Dalmasse, Kévin; Merkin, Viacheslav; Vourlidas, Angelos; Nychka, Doug; Flyer, Natasha; Arge, Charles Bibcode: 2021cosp...43E1736M Altcode: Modeling solar coronal mass ejections (CMEs) is very important for both understanding coronal physics and for improving the accuracy of space weather forecasts. While it is generally accepted that CMEs are primarily magnetic structures, the exact properties of these structures could differ in different models and events. A structure often considered is a spheromak, a toroidal twisted flux rope, which is ejected as a CME bubble. Another commonly considered structure is a twisted magnetic flux rope, which is anchored to the solar surface while its upper portion is ejected into interplanetary space. In this talk we will show how a well-known analytical magnetohydrodynamic CME model (Gibson \& Low, 1998), generally considered a spheromak-like model, can be extended to represent both standard spheromak and twisted flux tube configurations, as well as other topologically distinct magnetic structures. We will begin with the general parameters of the flux rope in this model (such as size and stretching parameters), and explore topologically different congurations possible with their variation. We then present several dimensionless parameters which can be varied to achieve these different configurations and consider how they relate to directly observable quantities. This work is particularly timely, as the Gibson \& Low model is been increasingly used as input to numerical models of the solar corona and the heliosphere. The ability to generate topologically different magnetic congurations within this analytic solution is of great value to such simulations, as well as for the studies of the flux ropes forming in the solar corona. Title: Extended, Kilogauss Bald Patches in the Super-Flaring Solar Active Region 12673 Authors: Sun, Xudong; Gibson, Sarah; Welsch, Brian; Titov, Viacheslav Bibcode: 2021cosp...43E1730S Altcode: Bald patch (BP) is a magnetic topological feature where U-shaped field lines turn tangent to the photosphere. When accompanied by shear, BPs suggest the existence of pre-eruption magnetic flux ropes (MFRs). Previous studies often found them in young solar active regions (ARs) with patchy flux emergence, or decaying ARs with weaker magnetic field. Here we report on a coherent, strong-field example observed in the super-flaring AR 12673. The central BP, located in a narrow delta_x000E_-spot penumbral lane, extended over 10 Mm with field strength above 2 kG. It formed over a period 10 hr, which featured fast Doppler downflow, gradual azimuth rotation, field strength reduction, and field gradient enhancement. It then rapidly disintegrated during a GOES X9 flare. Coronal field extrapolation reveals a low-lying, kilogauss MFR with over two turns of twist wrapped inside three intersecting BP separatrices (BPSs). The early-phase flare ribbons coincide with BPS foot prints. We discuss the BP formation mechanism such as flux cancellation, its stability condition, and its role in the eruption. Title: WHPI: A New Initiative on Solar Minimum Authors: De Toma, Giuliana; Gibson, Sarah; Qian, Liying; Thompson, Barbara Bibcode: 2021cosp...43E.916D Altcode: The Whole Heliosphere and Planetary Interactions (WHPI) is an international initiative focused around the solar minimum period that aims to understand the interconnected Sun-heliospheric-planetary system. The simpler magnetic configuration and infrequency of solar eruptions makes solar minimum an ideal time to determine how the Sun's radiative output, magnetic field and outflowing solar wind plasma interact with the background heliosphere, the Earth and the other planets. WHPI follows two similar initiatives during the previous solar minima in 1996 and 2008-2009. The success of these efforts relies on a broad participation of scientists worldwide and across disciplines. In 2019-2020 WHPI coordinated 3 different observing campaigns, each a solar rotation long: The first was on Mar 12 - Apr 8, 2019 and targeted two large, recurrent coronal holes and the associated high-speed solar wind streams, the second one on Jun 29 - Jul 26 2019 was centered on the total solar eclipse, and the third one on Jan 15 - Feb 11 2020 corresponded to the 4th Parker Solar Probe (PSP) encounter when the Earth and many space observatories were near-radially aligned with PSP. We describe the WHPI effort as an example of interdisciplinary collaboration and report on the preliminary science results obtained during the WHPI campaigns. Title: Magnetofrictional Modeling of an erupting Pseudostreamer Authors: Karna, Nishu; Gibson, Sarah; DeLuca, Edward; Dalmasse, Kévin; Savcheva, Antonia; Tassev, Svetlin Bibcode: 2021cosp...43E1768K Altcode: In this study, we present a magnetic configuration of an erupting pseudostreamer observed on April 19, 2015 on the Southwest limb, embedding a prominence cavity. The eruption resulted in a relatively wide CME with a round front and prominence core intersected by a sharp plume as seen in SOHO/LASCO C2, a partial halo was observed. The prominence eruption begins with a slow rise and then evolves to a fast rise phase. We first construct a non-linear force free field (NLFFF) model of this erupting pseudostreamer using the flux rope insertion method. The NLFFF model produces the 3D coronal magnetic field constrained by observed coronal structures and the SDO/HMI photospheric magnetogram taken 3 days earlier. We then increase axial and poloidal flux in the model to make it unstable. The field configurations representing the eruption are not in force-free equilibrium. We magnetofrictionally evolve the model until the flux rope expands to three solar radii and compare the modeled CME propagation with the SOHO/LASCO C2 observations. We perform a topological analysis of the models in order to determine the location of quasi-separatrix layers (QSLs) and how the QSL locations are transferred as the simulation progresses. The model reproduced the LASCO C2 observation structure in the QSL map. The modeling and topological analysis results are fully consistent with the observed morphological features implying that we have captured the large magnetic structure of the erupting filament. Title: SunCET: The Sun Coronal Ejection Tracker Concept Authors: Mason, James Paul; Chamberlin, Phillip C.; Seaton, Daniel; Burkepile, Joan; Colaninno, Robin; Dissauer, Karin; Eparvier, Francis G.; Fan, Yuhong; Gibson, Sarah; Jones, Andrew R.; Kay, Christina; Kirk, Michael; Kohnert, Richard; Pesnell, W. Dean; Thompson, Barbara J.; Veronig, Astrid M.; West, Matthew J.; Windt, David; Woods, Thomas N. Bibcode: 2021JSWSC..11...20M Altcode: 2021arXiv210109215M The Sun Coronal Ejection Tracker (SunCET) is an extreme ultraviolet imager and spectrograph instrument concept for tracking coronal mass ejections through the region where they experience the majority of their acceleration: the difficult-to-observe middle corona. It contains a wide field of view (0-4 R⊙) imager and a 1 Å spectral-resolution-irradiance spectrograph spanning 170-340 Å. It leverages new detector technology to read out different areas of the detector with different integration times, resulting in what we call "simultaneous high dynamic range", as opposed to the traditional high dynamic range camera technique of subsequent full-frame images that are then combined in post-processing. This allows us to image the bright solar disk with short integration time, the middle corona with a long integration time, and the spectra with their own, independent integration time. Thus, SunCET does not require the use of an opaque or filtered occulter. SunCET is also compact - ~15 × 15 × 10 cm in volume - making it an ideal instrument for a CubeSat or a small, complementary addition to a larger mission. Indeed, SunCET is presently in a NASA-funded, competitive Phase A as a CubeSat and has also been proposed to NASA as an instrument onboard a 184 kg Mission of Opportunity. Title: Designing a New Coronal Magnetic Field Energy Diagnostic Authors: Corchado-Albelo, Marcel F.; Dalmasse, Kévin; Gibson, Sarah; Fan, Yuhong; Malanushenko, Anna Bibcode: 2021ApJ...907...23C Altcode: In the solar corona, the free energy, i.e., the excess in magnetic energy over a ground-state potential field, forms the reservoir of energy that can be released during solar flares and coronal mass ejections. Such free energy provides a measure of the magnetic field nonpotentiality. Recent theoretical and observational studies indicate that the presence of nonpotential magnetic fields is imprinted into the structures of infrared, off-limb, coronal polarization. In this paper, we investigate the possibility of exploiting such observations for mapping and studying the accumulation and release of coronal free magnetic energy, with the goal of developing a new tool for identifying "hot spots" of coronal free energy such as those associated with twisted and/or sheared coronal magnetic fields. We applied forward modeling of infrared coronal polarimetry to three-dimensional models of nonpotential and potential magnetic fields. From these we defined a quantitative diagnostic of nonpotentiality that in the future could be calculated from a comparison of infrared, off-limb, coronal polarization observations from, e.g., the Coronal Multi-channel Polarimeter or the Daniel K. Inouye Solar Telescope, and the corresponding polarization signal forward-modeled from a potential field extrapolated from photospheric magnetograms. We considered the relative diagnostic potential of linear and circular polarization, and the sensitivities of these diagnostics to coronal density distributions and assumed boundary conditions of the potential field. Our work confirms the capacity of polarization measurements for diagnosing nonpotentiality and free energy in the solar corona. Title: What does a magnetic flux rope look like? Authors: Gibson, Sarah Bibcode: 2021cosp...43E1744G Altcode: Solar magnetic flux ropes are often represented by the archetypal "slinky" toy. Although this may be a fair representation of the flux rope's magnetic field lines, the observational manifestation of the flux rope at different wavelengths may look entirely different. Forward modeling explicitly takes into account three crucial factors leading to the appearance of the flux rope: the physical state of the flux rope's plasma and magnetic field, the physical process that translates the physical state into an observable quantity (e.g., Thomson scattering, collisional excitation, Faraday rotation, etc., etc.), and finally the observer's position relative to the flux rope. We will use forward modeling to investigate the observable properties of flux ropes at multiple wavelengths and in a range of spatial contexts, including active regions and quiescent prominences, and CMEs in the corona and solar wind. Title: The Magnetic Skeleton of the Solar Corona Over Several Solar Rotations: Features, Analysis, and Community Availability Authors: Malanushenko, A. V.; Gibson, S. E.; Kucera, T. A.; McKenzie, D. E. Bibcode: 2020AGUFMSH041..02M Altcode: The magnetic field in the solar corona is thought to be the main driver for solar eruptive events, such as flares and coronal mass ejections. The coronal magnetic field is therefore important to study, but it is difficult to measure directly. Usually, it is studied through extrapolations based on photospheric magnetograms. As the corona is thought to be mostly in a state of equilibrium, equations of low-beta equilibria are often used in order to study the structure of the field, or to estimate the magnetic energy. One of the complications that arise from this approach is that the solar photosphere itself is not a low-beta equilibrium.

Images of the solar corona in extreme ultraviolet (EUV) do not directly measure the magnetic field; however, they do reveal structures from which information about magnetic field can be inferred. For example, coronal loops are thought to trace out magnetic field lines, coronal cavities are bounded by magnetic surfaces, coronal holes are areas of magnetic flux that is open to the heliosphere, and plasma flows are also thought to follow lines of magnetic field. In other wavelengths, coronal spectropolarimetry (SP) can provide us with proxies for magnetic field strength and reveal plasma flows along the line of sight, off the limb. The EUV images and SP data are frequently used to validate magnetic field models. Additionally, new models are emerging which can use these data directly as additional constraints.

We aggregate available relevant features seen in EUV and SP data for several solar rotations. We apply existing techniques to infer 3D constraints on the magnetic field from these data. The result is an interactive 3D model based on these constraints for a full rotation, or a "magnetic skeleton". It is modular, so individual constraints can be easily added, or only selected constraints can be used. The features could be exported in either graphical or numerical form. The possible uses of our approach include validation of magnetic models that are based on extrapolations alone. Some models allow for using additional coronal constraints directly. These 'skeletons' can also be used in non-magnetic-modeling applications, as a simple, interactive reference for features seen in a given rotation. We make the models available to the community and show how to obtain and use them. Title: Tracking CME substructure evolution through the solar wind Authors: Gibson, S. E.; DeForest, C.; de Koning, C. A.; Fan, Y.; Malanushenko, A. V.; Merkin, V. G.; Provornikova, E.; Thompson, B. J.; Webb, D. F. Bibcode: 2020AGUFMSH0280005G Altcode: Future coronagraphs and heliospheric imagers, in particular those to be launched on the PUNCH mission, will have the capability to track the evolution of CME substructures as the CME moves through and interacts with the solar wind. We present analysis using polarization data obtained from forward modeling simulations of CMEs in the corona and inner heliosphere. We use these data to track the evolution of substructures in three dimensions, and consider the diagnostic potential of internal substructure vs structure at the front of the CME. In particular, we develop methods for extracting information about chirality of CME magnetic flux ropes from polarization data. Title: The Polar Field Reversal Process over Five Solar Cycles Using the McIntosh Archive Authors: Webb, D. F.; Emery, B. A.; Gibson, S. E.; Hewins, I. M.; McFadden, R.; Kuchar, T. A. Bibcode: 2020AGUFMSH0020021W Altcode: We study the polar magnetic field reversal process over five solar cycles (SCs 19-23, Dec. 1954 - Aug. 2009) using the recently digitized McIntosh Archive (McA) of solar synoptic maps. This data set allows the tracking of features such as filaments, polarity inversion lines (PILs), coronal hole boundaries and sunspots over many consecutive Carrington rotations. Here we follow the evolution of the polar magnetic regions of the Sun and how the rush-to-the-poles and other patterns occur during the period when the polar fields reverse around each SC maximum. This process was first studied in detail for SCs 20 and 21 by Webb et al. (1984). The goal then as now is to use the rush-to-the-poles and CH boundary mapping to better constrain solar interior and dynamo models. We use the McA data sets to determine the timing and lags among these events around the maximum of each SC in each hemisphere: the sunspot number peak, the polarity reversal, the disappearance of the polar crown filaments and PIL, the first appearance of mid-latitude CHs of new-cycle polarity, and the earliest complete coverage of each pole by a coronal hole. With the newly processed McA, we can now extend this type of study over five consecutive SCs through SC 23. Title: Oscillations in Secondary to Primary Polar Crown Polarity Inversion Lines around Solar Maximum over Five Solar Cycles Authors: Emery, B. A.; Webb, D. F.; Gibson, S. E.; Hewins, I. M.; McFadden, R.; Kuchar, T. A. Bibcode: 2020AGUFMSH006..06E Altcode: We undertake a five solar-cycle (SC19-23, Dec. 1954 - Aug. 2009) study of oscillations in the high-latitude polarity inversion lines (PILs) using the recently digitized McIntosh Archive of solar synoptic maps. We look at the evolution of the primary PIL, which is the nearly continuous polar crown filament (PCF) line bounding the polar coronal hole (CH). The secondary PIL consists of neutral line segments equatorward of the primary PIL, and it becomes a nearly continuous PCF line at the end of the rush to the poles before solar maximum when the polar polarity reverses with the primary PIL disappearing, and the secondary PIL becomes the primary PIL with the new polarity. This new primary PIL achieves a maximum poleward latitude of ~+/-57 degrees, and then relaxes equatorward in oscillations of 2-5 degrees of latitude with periods between ~10-35 Carrington Rotations (CRs). In 2005, we saw equatorward drops in the PIL and CH boundaries that started in the southern hemisphere pole and ended in the north pole, with ~35CR wave periods before and ~20CR after the break. The oscillations and breaks are new aspects of the general evolutionary patterns of surface features that need to be accounted for by interior dynamo models. Title: Contemporary Analysis Methods for Coronagraph and Heliospheric Imager Data Authors: Thompson, B. J.; Attie, R.; Chhiber, R.; Cranmer, S. R.; DeForest, C.; Gallardo-Lacourt, B.; Gibson, S. E.; Jones, S. I.; Moraes Filho, V.; Reginald, N. L.; Uritsky, V. M.; Viall, N. M. Bibcode: 2020AGUFMSH031..05T Altcode: Coronagraphs, polarimeters, and heliospheric imagers are providing new insight into how structures in the solar wind form and develop as they flow from the inner corona into the heliosphere. With this comes a whole new frontier of physical observables in 3D, including kinetic (velocity and acceleration), thermodynamic (density, temperature, and shock boundary), and magnetic field properties. These measurements inform and challenge models of global solar wind flow, turbulence, and CME propagation. We will discuss recent advances in quantifying physical properties of the corona and solar wind using coronagraph and heliospheric imager data, and make predictions of what new models and instrumentation (including the in-development PUNCH mission) will bring us in the future. Title: The Solaris Solar Polar Mission: Exploring one of the last Unexplored Regions of the Solar System Authors: Hassler, D.; Newmark, J. S.; Gibson, S. E.; Duncan, N. A.; Gosain, S.; Harvey, J. W.; Wuelser, J. P.; Woods, T. N. Bibcode: 2020AGUFMSH0110003H Altcode: The solar poles are one of the last unexplored regions of the solar system. Although Ulysses flew over the poles in the 1990s, it did not have remote sensing instruments onboard to probe the Sun's polar magnetic field or surface/sub-surface flows. I will discuss Solaris, a proposed Solar Polar MIDEX mission to fly over the solar poles at 75 degrees inclination to address key outstanding, breakthrough problems in solar physics, & fill holes in our scientific understanding that will not be addressed by current or planned future missions. Such a small, focused, "paradigm-breaking" mission is achievable now with existing launchers and technology, & is enabled by miniaturized instrument technology such as the Compact Doppler Magnetograph (CDM), developed for Solaris to provide magnetic field & Doppler velocity measurements in a small (15kg) package. Solaris will also provide enabling observations for space weather research & stimulate future research through new unanticipated discoveries. Title: WHPI Synoptic Coronal Hole Maps and Solar Wind Studies Authors: Hewins, I. M.; Gibson, S. E. Bibcode: 2020AGUFMSH0180003H Altcode: Ian Hewins(1), Sarah Gibson (1), Barbara Emery-Geiger (1)

1 = HAO/NCAR Title: Coronagraphy from the Ground: Current and Future Observations Authors: Burkepile, J.; Tomczyk, S.; Zmarzly, P.; de Wijn, A.; Gibson, S. E.; de Toma, G.; Galloy, M. D. Bibcode: 2020AGUFMSH031..03B Altcode: Ground-based coronagraphs provided the first observations of the ethereal corona outside of a total solar eclipse in 1931. Invented by Bernard Lyot, coronagraphs enabled long time-series images and movies of the emission line corona. Advances in technology have led to more sophisticated coronagraphs capable of observing polarized light from spectral lines and the coronal continuum. These observations, coupled with advances in our understanding of resonance scattering-induced polarization, have greatly facilitated our knowledge of coronal physics and explosive events such as Coronal Mass Ejections (CMEs). While space-based coronagraphs provide spectacular observations of the extended corona, ground-based coronagraphs continue to contribute important, unique and complementary inner coronal observations at a fraction of the cost of a space-based mission. We discuss current ground-based solar coronagraphs, observations and data products and highlight future instruments and network capabilities and benefits. Title: Snapshots of Solar Minimum: Data and Model Results From the Past Two Solar Minima Authors: Thompson, B. J.; Gibson, S. E. Bibcode: 2020AGUFMSH0180002T Altcode: We present an overview of the data and models collected for the Whole Sun Month (WSM; 1996) Whole Heliosphere Interval (WHI; 2008), two international campaigns to study the three-dimensional solar-heliospheric-planetary connected system near solar minimum. The data and models from WSM, which occurred during the solar minimum between Cycles 22 and 23, provided new insight into how solar magnetic structure forms the corona and inner heliosphere. WSM inspired the Whole Heliosphere Interval campaign during the next solar minimum, and the scientific goals expanded to study how solar minimum structures affect processes in geospace. The data from WHI extended from below the solar photosphere, through interplanetary space, and down to Earth's mesosphere. Nearly 200 people participated in aspects of WHI studies, analyzing and interpreting data from nearly 100 instruments and models in order to elucidate the physics of fundamental heliophysical processes. WSM and WHI studies traced the solar activity and structure into the heliosphere and geospace, and provided new insight into the nature of the interconnected heliophysical system near solar minimum. This presentation gives insight into the motivation for the Whole Heliosphere and Planetary Interactions campaigns. Title: SunCET: A CubeSat Mission Dedicated to the Middle Corona Authors: Mason, J. P.; Seaton, D. B.; Chamberlin, P. C.; Burkepile, J.; Colaninno, R. C.; Dissauer, K.; Eparvier, F. G.; Fan, Y.; Gibson, S. E.; Jones, A. R.; Kay, C.; Kirk, M. S.; Kohnert, R.; Thompson, B. J.; Veronig, A.; West, M. J.; Woods, T. N. Bibcode: 2020AGUFMSH0300006M Altcode: No abstract at ADS Title: Tracking Movement of Coronal Holes from Long Term McA Data Authors: Harris, J.; Dikpati, M.; Gibson, S. E.; Hewins, I. M. Bibcode: 2020AGUFMSH0020010H Altcode: Features on the surface of the Sun and other layers of the solar atmosphere are constantly changing, due to its magnetic field. In 1964, Patrick Mcintosh, a scientist at NOAA's Space Environment Center, began creating hand-drawn synoptic maps of the sun's magnetic features and produced nearly 45 years' (about four solar cycles) worth of these maps. To prevent these maps from being lost,all of these maps have been digitized in the Mcintosh Archives (McA). This summer, we processed many years' worth of this data to create stack plots, which are essentially plots of latitude bands stacked in time. This allows us to track the movement of solar features, particularly coronal holes. We calculated the centroids of the coronal holes in successive Carrington rotations, and estimated the slopes of these patterns as the coronal holes evolve. To calculate the centroids, we developed a new method and utilized it with numerical tools in Mathematica. This method utilizes the Fourier Transform to find an approximation of the outlines of coronal holes with a series of sinusoids in parametric form. These parametric equations are then plugged into line integrals to calculate the centroids. Our method of centroid calculations is accurate in most cases and is comparable to other accurate methods. Using the slopes of coronal hole patterns we estimated the velocities and found that the velocity is more prograde when the coronal holes are at low latitudes, and more retrograde at high latitudes, which is an expected result of differential rotation. The velocity was zero at a lower latitude than expected based on where the Carrington rotation rate is defined at the photosphere. This implies that the movement of coronal holes is being influenced by deeply rooted magnetic field lines below the surface. By superimposing differential rotation on coronal hole migration velocities and estimating the difference between the two, we can investigate what other factors influence coronal hole movement, such as Rossby waves. Learning more about these waves will tell us more about other forms of solar weather and could help us predict CMEs. This information could not only advance solar physics but also help keep our planet safe . Title: Ensemble modeling of interplanetary CMEs with data-constrained internal magnetic flux rope Authors: Provornikova, E.; Merkin, V. G.; Malanushenko, A. V.; Gibson, S. E.; Vourlidas, A.; Arge, C. N. Bibcode: 2020AGUFMSH0030016P Altcode: Understanding the evolution of the CME magnetic structure as it propagates through the interplanetary space is a key aspect in the development of forecasting of magnetic properties of a CME arriving at Earth and thus its impact on space weather. To analyze processes of interplanetary CME (ICME)/solar-wind interactions and the role of CME flux rope specification and solar wind background structure, we take a statistical approach and perform thousands of data-driven MHD simulations of ICME propagation in the inner heliosphere. Data-driven modeling of ICMEs in the inner heliosphere (starting beyond the critical surface in the corona) presents an attractive and computationally feasible approach, since it bypasses the complex problem of CME initiation and eruption in the corona. We simulate the propagation of ICMEs in the inner heliosphere using a global model driven at the coronal boundary by the Wang-Sheeley-Arge (WSA)-ADAPT model. ICMEs are initiated at 21.5 solar radii using an MHD analytical Gibson-Low (G&L) model of a self-similarly expanding magnetic flux rope with defining parameters (e.g., location, magnetic topology, width, magnetic field strength, speed, orientation). The ICME propagation is simulated using the inner heliosphere version of the Grid Agnostic MHD for Extended Research Applications (GAMERA) MHD model, which is a reinvention of the high-heritage Lyon-Fedder-Mobarry (LFM) code. A set of values for each of the defining G&L parameters was constrained by statistical representation of solar CME observations. With the aim to span the solar cycle, we model ICME propagation in different solar wind backgrounds corresponding to rising, maximum, declining and minimum solar cycle phases. A grid of G&L parameters and four solar wind backgrounds constitute a parameter space for thousands of MHD ICME runs. For each of the simulations we extract synthetic in-situ observations of ICME as it passes Earth and synthetic white-light images of an ICME as it propagates in the interplanetary space. We present an analysis of produced distributions of ICME parameters and characteristics. Title: The Polarimeter to UNify the Corona and Heliosphere (PUNCH) Small Explorer Mission: Status and Next Steps Authors: DeForest, C. E.; Killough, R.; Gibson, S. E.; Beasley, M.; Henry, A.; Laurent, G. T.; Colaninno, R. C. Bibcode: 2020AGUFMSH0280002D Altcode: The Polarimeter to UNify the Corona and Heliosphere (PUNCH) is a NASA Small Explorer mission, to understand the solar corona and young solar wind as a complete system. Science objectives are to measure and understand how the ambient solar wind arises from the corona, and to understand how transient events (such as CMEs) propagate and evolve in the inner heliosphere. PUNCH uses direct, global, spatially continuous, three dimensional imaging in polarized visible light, to observe the outer corona and inner heliosphere as elements of a single, connected system. PUNCH comprises four matched and synchronized small-satellite observatories, operating as a "virtual instrument" to image Thomson-scattered light from low-Earth orbit. PUNCH is the first coronal and solar wind imaging mission designed specifically to produce 3D images from a single vantage point using the polarization properties of Thomson scattering. In addition, it will produce routine, several-times-per-day maps of solar wind flow throughout the top of the corona and bottom of the inner heliosphere, based on motion analysis of the image stream. PUNCH has an open data policy and is seeking scientific engagement throughout the heliophysics community.

PUNCH is wrapping up its Phase B (preliminary design), and is working toward a 2023 launch for a two-year nominal mission. We present a very brief overview of the mission, describe current status and next steps, and indicate how to engage with the PUNCH science team and upcoming mission. Title: Untangling the global coronal magnetic field with multiwavelength observations Authors: Gibson, S. E.; Malanushenko, A.; de Toma, G.; Tomczyk, S.; Reeves, K.; Tian, H.; Yang, Z.; Chen, B.; Fleishman, G.; Gary, D.; Nita, G.; Pillet, V. M.; White, S.; Bąk-Stęślicka, U.; Dalmasse, K.; Kucera, T.; Rachmeler, L. A.; Raouafi, N. E.; Zhao, J. Bibcode: 2020arXiv201209992G Altcode: Magnetism defines the complex and dynamic solar corona. Coronal mass ejections (CMEs) are thought to be caused by stresses, twists, and tangles in coronal magnetic fields that build up energy and ultimately erupt, hurling plasma into interplanetary space. Even the ever-present solar wind possesses a three-dimensional morphology shaped by the global coronal magnetic field, forming geoeffective corotating interaction regions. CME evolution and the structure of the solar wind depend intimately on the coronal magnetic field, so comprehensive observations of the global magnetothermal atmosphere are crucial both for scientific progress and space weather predictions. Although some advances have been made in measuring coronal magnetic fields locally, synoptic measurements of the global coronal magnetic field are not yet available. We conclude that a key goal for 2050 should be comprehensive, ongoing 3D synoptic maps of the global coronal magnetic field. This will require the construction of new telescopes, ground and space-based, to obtain complementary, multiwavelength observations sensitive to the coronal magnetic field. It will also require development of inversion frameworks capable of incorporating multi-wavelength data, and forward analysis tools and simulation testbeds to prioritize and establish observational requirements on the proposed telescopes. Title: The Evolution of Coronal Holes over Three Solar Cycles Using the McIntosh Archive Authors: Hewins, Ian M.; Gibson, Sarah E.; Webb, David F.; McFadden, Robert H.; Kuchar, Thomas A.; Emery, Barbara A.; McIntosh, Scott W. Bibcode: 2020SoPh..295..161H Altcode: Using the McIntosh Archive of solar features, we analyze the evolution of coronal holes over more than three solar cycles. We demonstrate that coronal-hole positions and lifetimes change significantly on time scales from months to years, and that the pattern of these changes is clearly linked to the solar-activity cycle. We demonstrate that the lifetimes of low-latitude coronal holes are usually less than one rotation but may extend to almost three years. When plotted over time, the positions of low-latitude coronal holes that remain visible for over one rotation track the sunspot butterfly diagram in terms of their positions on the Sun over a solar cycle. Finally, we confirm that coronal holes do not in general rigidly rotate. Title: Temperature of a long-lived solar coronal cavity Authors: Bąk-Stęślicka, Urszula; Gibson, Sarah E.; Stęślicki, Marek Bibcode: 2020past.conf..169B Altcode: We have analysed a long-lived coronal cavity observed from 17 March 2012 to 21 March 2012. For this cavity we applied a differential emission measure method to obtain both a temperature distribution and the average temperature over all five observational days. We find that the cavity is filled with material hotter than its surroundings. The temperature remains stable during all five days. Title: Major Scientific Challenges and Opportunities in Understanding Magnetic Reconnection and Related Explosive Phenomena in Solar and Heliospheric Plasmas Authors: Ji, H.; Karpen, J.; Alt, A.; Antiochos, S.; Baalrud, S.; Bale, S.; Bellan, P. M.; Begelman, M.; Beresnyak, A.; Bhattacharjee, A.; Blackman, E. G.; Brennan, D.; Brown, M.; Buechner, J.; Burch, J.; Cassak, P.; Chen, B.; Chen, L. -J.; Chen, Y.; Chien, A.; Comisso, L.; Craig, D.; Dahlin, J.; Daughton, W.; DeLuca, E.; Dong, C. F.; Dorfman, S.; Drake, J.; Ebrahimi, F.; Egedal, J.; Ergun, R.; Eyink, G.; Fan, Y.; Fiksel, G.; Forest, C.; Fox, W.; Froula, D.; Fujimoto, K.; Gao, L.; Genestreti, K.; Gibson, S.; Goldstein, M.; Guo, F.; Hare, J.; Hesse, M.; Hoshino, M.; Hu, Q.; Huang, Y. -M.; Jara-Almonte, J.; Karimabadi, H.; Klimchuk, J.; Kunz, M.; Kusano, K.; Lazarian, A.; Le, A.; Lebedev, S.; Li, H.; Li, X.; Lin, Y.; Linton, M.; Liu, Y. -H.; Liu, W.; Longcope, D.; Loureiro, N.; Lu, Q. -M.; Ma, Z-W.; Matthaeus, W. H.; Meyerhofer, D.; Mozer, F.; Munsat, T.; Murphy, N. A.; Nilson, P.; Ono, Y.; Opher, M.; Park, H.; Parker, S.; Petropoulou, M.; Phan, T.; Prager, S.; Rempel, M.; Ren, C.; Ren, Y.; Rosner, R.; Roytershteyn, V.; Sarff, J.; Savcheva, A.; Schaffner, D.; Schoeffier, K.; Scime, E.; Shay, M.; Sironi, L.; Sitnov, M.; Stanier, A.; Swisdak, M.; TenBarge, J.; Tharp, T.; Uzdensky, D.; Vaivads, A.; Velli, M.; Vishniac, E.; Wang, H.; Werner, G.; Xiao, C.; Yamada, M.; Yokoyama, T.; Yoo, J.; Zenitani, S.; Zweibel, E. Bibcode: 2020arXiv200908779J Altcode: Magnetic reconnection underlies many explosive phenomena in the heliosphere and in laboratory plasmas. The new research capabilities in theory/simulations, observations, and laboratory experiments provide the opportunity to solve the grand scientific challenges summarized in this whitepaper. Success will require enhanced and sustained investments from relevant funding agencies, increased interagency/international partnerships, and close collaborations of the solar, heliospheric, and laboratory plasma communities. These investments will deliver transformative progress in understanding magnetic reconnection and related explosive phenomena including space weather events. Title: Convolutional Neural Networks for Predicting the strength of the Near-Earth Magnetic Field Caused by Interplanetary Coronal Mass Ejections Authors: Malanushenko, Anna; Flyer, Natasha; Gibson, Sarah Bibcode: 2020FrASS...7...62M Altcode: In this paper, we explore the potential of neural networks for making space weather predictions based on near-Sun observations. Our second goal is to determine the extent to which coronal polarimetric observations of erupting structures near the Sun encode sufficient information to predict the impact these structures will have on Earth. We focus on predicting the maximal southward component of the magnetic field ("-Bz") inside an interplanetary coronal mass ejection (ICME) as it impacts the Earth. We use Gibson&Low (G&L) self-similarly expanding flux rope model (Gibson&Low 1998), which allows to consider CMEs with varying location, orientation, size, and morphology. We vary 5 parameters of the model to alter these CME properties, and generate a large database of synthetic CMEs (over 36k synthetic events). For each model CME, we synthesize near-Sun observations, as seen from an observer in quadrature (assuming the CME is directed Earthwards), of either three components of the vector magnetic field ("Experiment 1"), or of synthetic Stokes images, ("Experiment 2"). We then allow the flux rope to expand and record max(-Bz) as the ICME passes 1AU. We further conduct two separate machine learning experiments and develop two different regression-based deep convolutional neural networks (CNNs) to predict max(-Bz) based on these two kinds of the near-Sun input data. Experiment 1 is a proof of concept, to see if a 3-channel CNN (hereafter CNN1), similar to those used in RGB image recognition, can reproduce the results of the self-similar (i.e. scale-invariant) expansion of the G&L model. Experiment 2 is less trivial, as Stokes vector is not linearly related to B, and the line-of-sight integration in the optically thin corona presents additional difficulties for interpreting the signal. This second CNN (hereafter CNN2), although resembling CNN1 in Experiment 1, will have a different number of layers and set of hyperparameters due to a much more complicated mapping between the input and output data. We find that, given vector B, CNN1 can predict max(-Bz) with 97% accuracy, and for the Stokes vector as input, CNN2 can predict max(-Bz) with 95%, both measured in the relative root square error. Title: The Science Case for the $4{\pi}$ Perspective: A Polar/Global View for Studying the Evolution & Propagation of the Solar Wind and Solar Transients Authors: Vourlidas, A.; Gibson, S.; Hassler, D.; Hoeksema, T.; Linton, M.; Lugaz, N.; Newmark, J. Bibcode: 2020arXiv200904880V Altcode: To make progress on the open questions on CME/CIR propagation, their interactions and the role and nature of the ambient solar wind, we need spatially resolved coverage of the inner heliosphere -- both in-situ and (critically) imaging -- at temporal scales matching the evolutionary timescales of these phenomena (tens of minutes to hours), and from multiple vantage points. The polar vantage is uniquely beneficial because of the wide coverage and unique perspective it provides. The ultimate goal is to achieve full $4\pi$ coverage of the solar surface and atmosphere by 2050. Title: Global maps of the magnetic field in the solar corona Authors: Yang, Zihao; Bethge, Christian; Tian, Hui; Tomczyk, Steven; Morton, Richard; Del Zanna, Giulio; McIntosh, Scott W.; Karak, Bidya Binay; Gibson, Sarah; Samanta, Tanmoy; He, Jiansen; Chen, Yajie; Wang, Linghua Bibcode: 2020Sci...369..694Y Altcode: 2020arXiv200803136Y Understanding many physical processes in the solar atmosphere requires determination of the magnetic field in each atmospheric layer. However, direct measurements of the magnetic field in the Sun’s corona are difficult to obtain. Using observations with the Coronal Multi-channel Polarimeter, we have determined the spatial distribution of the plasma density in the corona and the phase speed of the prevailing transverse magnetohydrodynamic waves within the plasma. We combined these measurements to map the plane-of-sky component of the global coronal magnetic field. The derived field strengths in the corona, from 1.05 to 1.35 solar radii, are mostly 1 to 4 gauss. Our results demonstrate the capability of imaging spectroscopy in coronal magnetic field diagnostics. Title: Reconstructing the Coronal Magnetic Field: The Role of Cross-Field Currents in Solution Uniqueness Authors: Mathews, N.; Flyre, N.; Gibson, S. Bibcode: 2020SPD....5121004M Altcode: We present a new 3D magnetohydrostatic (MHS) direct elliptic solver for extrapolating the coronal magnetic field from photospheric boundary conditions in a manner consistent with an assumed plasma distribution. We use it to study the uniqueness of the reconstructed magnetic field as a function of how significant the plasma forcing is on the force balance of the magnetic field. To this end, we consider an analytic MHS model as ground truth. The model uses two free parameters to decompose the current into two parts: a magnetic-field aligned component and a cross-field component. We perform a comprehensive study of the 2D parameter space to understand under what conditions the ground truth can be reproduced uniquely. We find that current oriented perpendicular to the magnetic field has a smaller solution space than the same amount of current oriented parallel to the magnetic field, and so MHS regimes with larger proportions of plasma-related forcing may be a promising avenue towards finding unique magnetic field reconstructions. Title: Reconstructing the Coronal Magnetic Field: The Role of Cross-field Currents in Solution Uniqueness Authors: Mathews, Nathaniel H.; Flyer, Natasha; Gibson, Sarah E. Bibcode: 2020ApJ...898...70M Altcode: We present a new 3D magnetohydrostatic (MHS) direct elliptic solver for extrapolating the coronal magnetic field from photospheric boundary conditions in a manner consistent with an assumed plasma distribution. We use it to study the uniqueness of the reconstructed magnetic field as a function of how significant the plasma forcing is on the force balance of the magnetic field. To this end, we consider an analytic MHS model as ground truth. The model uses two free parameters to decompose the current into two parts: a magnetic-field-aligned component and a cross-field component. We perform a comprehensive study of the 2D parameter space to understand under what conditions the ground truth can be reproduced uniquely. We find that current oriented perpendicular to the magnetic field has a smaller solution space than the same amount of current oriented parallel to the magnetic field, and so MHS regimes with larger proportions of plasma-related forcing may be a promising avenue toward finding unique magnetic field reconstructions. Title: The Solaris Solar Polar Mission Authors: Hassler, Donald M.; Newmark, Jeff; Gibson, Sarah; Harra, Louise; Appourchaux, Thierry; Auchere, Frederic; Berghmans, David; Colaninno, Robin; Fineschi, Silvano; Gizon, Laurent; Gosain, Sanjay; Hoeksema, Todd; Kintziger, Christian; Linker, John; Rochus, Pierre; Schou, Jesper; Viall, Nicholeen; West, Matt; Woods, Tom; Wuelser, Jean-Pierre Bibcode: 2020EGUGA..2217703H Altcode: The solar poles are one of the last unexplored regions of the solar system. Although Ulysses flew over the poles in the 1990s, it did not have remote sensing instruments onboard to probe the Sun's polar magnetic field or surface/sub-surface flows.We will discuss Solaris, a proposed Solar Polar MIDEX mission to revolutionize our understanding of the Sun by addressing fundamental questions that can only be answered from a polar vantage point. Solaris uses a Jupiter gravity assist to escape the ecliptic plane and fly over both poles of the Sun to >75 deg. inclination, obtaining the first high-latitude, multi-month-long, continuous remote-sensing solar observations. Solaris will address key outstanding, breakthrough problems in solar physics and fill holes in our scientific understanding that will not be addressed by current missions.With focused science and a simple, elegant mission design, Solaris will also provide enabling observations for space weather research (e.g. polar view of CMEs), and stimulate future research through new unanticipated discoveries. Title: Solar physics in the 2020s: DKIST, parker solar probe, and solar orbiter as a multi-messenger constellation Authors: Martinez Pillet, V.; Tritschler, A.; Harra, L.; Andretta, V.; Vourlidas, A.; Raouafi, N.; Alterman, B. L.; Bellot Rubio, L.; Cauzzi, G.; Cranmer, S. R.; Gibson, S.; Habbal, S.; Ko, Y. K.; Lepri, S. T.; Linker, J.; Malaspina, D. M.; Matthews, S.; Parenti, S.; Petrie, G.; Spadaro, D.; Ugarte-Urra, I.; Warren, H.; Winslow, R. Bibcode: 2020arXiv200408632M Altcode: The National Science Foundation (NSF) Daniel K. Inouye Solar Telescope (DKIST) is about to start operations at the summit of Haleakala (Hawaii). DKIST will join the early science phases of the NASA and ESA Parker Solar Probe and Solar Orbiter encounter missions. By combining in-situ measurements of the near-sun plasma environment and detail remote observations of multiple layers of the Sun, the three observatories form an unprecedented multi-messenger constellation to study the magnetic connectivity inside the solar system. This white paper outlines the synergistic science that this multi-messenger suite enables. Title: Major Scientific Challenges and Opportunities in Understanding Magnetic Reconnection and Related Explosive Phenomena throughout the Universe Authors: Ji, H.; Alt, A.; Antiochos, S.; Baalrud, S.; Bale, S.; Bellan, P. M.; Begelman, M.; Beresnyak, A.; Blackman, E. G.; Brennan, D.; Brown, M.; Buechner, J.; Burch, J.; Cassak, P.; Chen, L. -J.; Chen, Y.; Chien, A.; Craig, D.; Dahlin, J.; Daughton, W.; DeLuca, E.; Dong, C. F.; Dorfman, S.; Drake, J.; Ebrahimi, F.; Egedal, J.; Ergun, R.; Eyink, G.; Fan, Y.; Fiksel, G.; Forest, C.; Fox, W.; Froula, D.; Fujimoto, K.; Gao, L.; Genestreti, K.; Gibson, S.; Goldstein, M.; Guo, F.; Hesse, M.; Hoshino, M.; Hu, Q.; Huang, Y. -M.; Jara-Almonte, J.; Karimabadi, H.; Klimchuk, J.; Kunz, M.; Kusano, K.; Lazarian, A.; Le, A.; Li, H.; Li, X.; Lin, Y.; Linton, M.; Liu, Y. -H.; Liu, W.; Longcope, D.; Loureiro, N.; Lu, Q. -M.; Ma, Z-W.; Matthaeus, W. H.; Meyerhofer, D.; Mozer, F.; Munsat, T.; Murphy, N. A.; Nilson, P.; Ono, Y.; Opher, M.; Park, H.; Parker, S.; Petropoulou, M.; Phan, T.; Prager, S.; Rempel, M.; Ren, C.; Ren, Y.; Rosner, R.; Roytershteyn, V.; Sarff, J.; Savcheva, A.; Schaffner, D.; Schoeffier, K.; Scime, E.; Shay, M.; Sitnov, M.; Stanier, A.; TenBarge, J.; Tharp, T.; Uzdensky, D.; Vaivads, A.; Velli, M.; Vishniac, E.; Wang, H.; Werner, G.; Xiao, C.; Yamada, M.; Yokoyama, T.; Yoo, J.; Zenitani, S.; Zweibel, E. Bibcode: 2020arXiv200400079J Altcode: This white paper summarizes major scientific challenges and opportunities in understanding magnetic reconnection and related explosive phenomena as a fundamental plasma process. Title: Evolution of the geoeffective April 5, 2010 CME in the inner heliosphere: A global MHD model with a data-constrained magnetic flux rope specification. Authors: Provornikova, E.; Merkin, V. G.; Gibson, S. E.; Malanushenko, A. V.; Arge, C. N.; Vourlidas, A. Bibcode: 2019AGUFMSH42A..03P Altcode: Modeling the evolution of internal magnetic structure of interplanetary coronal mass ejections (ICMEs) is important both for space weather prediction and for basic understanding of magnetized space plasma interactions. Data-driven modeling of ICMEs in the inner heliosphere (starting beyond the critical surface in the corona) presents an attractive and computationally feasible approach, since it bypasses the complex problem of CME initiation and eruption in the corona. Using this approach, we simulate the propagation of ICMEs through the inner heliosphere using a global model driven at the coronal boundary by the Wang-Sheeley-Arge (WSA)-ADAPT model. ICMEs are initiated at 20 solar radii (Rs) using a magnetohydrodynamic (MHD) analytical Gibson-Low (GL) model of a self-similarly expanding magnetic flux rope with parameters (e.g., location, geometry, speed, orientation) constrained by white-light coronograph observations. The ICME propagation is simulated using the Grid Agnostic MHD for Extended Research Applications (GAMERA) MHD model, which is a recent reinvention of the high-heritage Lyon-Fedder-Mobarry (LFM) code. We apply this approach to the study of a geoeffective ICME which arrived at Earth on April 5, 2010. This ICME appeared bright in SOHO/LASCO and STEREO coronagraphs allowing derivation of its parameters near the Sun thus constraining its properties in our model. However, the orientation of the flux rope was not determined uniquely from the observations. It was also not clear which part of the ICME hit Earth and caused the severe geomagnetic storm. By comparing synthetic white-light images derived from our MHD modeling with images from SOHO/LASCO and STEREO/HI1 and HI2, we shed light on the ICME initial orientation and it evolution due to the interaction with the background solar wind. We further compare the modeling results with ACE observations at 1 AU and discuss which part of the CME was probed by the spacecraft. Title: Gibson & Low Flux Rope Model: More Than a Spheromak! Authors: Malanushenko, A. V.; Gibson, S. E.; Provornikova, E.; Merkin, V. G.; Vourlidas, A.; Arge, C. N.; Dalmasse, K.; Nychka, D. W.; Flyer, N. Bibcode: 2019AGUFMSH11C3397M Altcode: Modeling solar coronal mass ejections (CMEs) is very important for both understanding coronal physics and for improving the accuracy of space weather forecasts. While it is generally accepted that CMEs are primarily magnetic structures, the exact properties of these structures could differ in different models and events. A structure often considered is a spheromak, a toroidal twisted flux rope, which is ejected as a CME bubble. Another commonly considered structure is a twisted magnetic flux rope, which is anchored to the solar surface while its upper portion is ejected into interplanetary space. In this talk we will show how a well-known analytical magnetohydrodynamic CME model (Gibson&Low, 1998), generally considered a spheromak-like model, can be extended to represent both standard spheromak and twisted flux tube configurations, as well as other topologically distinct magnetic structures. We will begin with the general parameters of the flux rope in this model (such as size and stretching parameters), and explore topologically different configurations possible with their variation. We then present several dimensionless parameters which can be varied to achieve these different configurations and consider how they relate to directly observable quantities. This work is particularly timely, as the Gibson&Low model is been increasingly used as input to numerical models of the solar corona and the heliosphere. The ability to generate topologically different magnetic configurations within this analytic solution is of great value to such simulations, as well as for the studies of the flux ropes forming in the solar corona. Title: Thermal properties of coronal cavities Authors: Steslicki, M.; Bak-Steslicka, U.; Gibson, S. E. Bibcode: 2019AGUFMSH11C3408S Altcode: We have analyzed few dozen of cavities observed between 2012 and 2018 by AIA/SDO, from solar activity maximum to minimum. For each cavity we applied a Differential Emission Measure method to obtain both a temperature distribution and a value of average temperature. We find that cavities are filled with material hotter than surrounding streamer with temperatures in the range of 1.6-2.2 MK. Differences between temperatures of cavities and surrounding streamers are in the range of 0.1 - 0.3 MK. We found that temperatures of both cavities and streamers vary as a function of different phases of solar activity. Title: Advances in coronal spectropolarimetry Authors: Gibson, S. E. Bibcode: 2019AGUFMSH33A..03G Altcode: Our understanding of energetic processes at the Sun is held back by our current lack of basic scientific understanding of CME magnetic origins and evolution, and of the coronal magnetism that structures and drives the solar wind. This motivates the development of spectropolarimetric instrumentation capable of probing the solar magnetothermal atmosphere at multiple heights, with sensitivity to magnetism of varying strength. I will describe recent progress, future upgrades, and long-term outlook for instrumentation capable of coronal magnetometry from infrared through visible through ultraviolet wavelengths. In particular, I will discuss how new capabilities arising from these instruments will shed a new light on the storage and release of magnetic energy, CME structure and dynamics, and the role of waves in solar atmospheric heating and solar wind acceleration. Title: PUNCH: a new view on the middle corona Authors: Gibson, S. E.; DeForest, C. Bibcode: 2019AGUFMSH13A..06G Altcode: The Polarimeter to UNify the Corona and Heliosphere (PUNCH) has recently been selected by NASA as a Small Explorer mission, to be launched as early as 2022. PUNCH uses a constellation of three wide-field heliospheric imagers and a central near-field coronagraphic imager to span the interface between the corona and the inner heliosphere. Polarized and unpolarized images will be obtained with greater than ten times the sensitivity of current instruments in the region covering 6-15 solar radii, i.e., the upper portion of the "middle corona". This will provide unprecedented views of the global structure of fast/slow wind flow boundaries, CME substructure and chirality, and the Alfven zone. This last is of particular interest to this session, because the riotous torrent that is the young solar wind implies the boundary between magnetically-dominated and wind-dominated plasma is likely to be fractal and space-filling. Thus, it is a zone that likely riddles the middle corona. Title: Coronal Solar Magnetism Observatory Science Objectives Authors: Gibson, S. E.; Tomczyk, S.; Burkepile, J.; Casini, R.; DeLuca, E.; de Toma, G.; de Wijn, A.; Fan, Y.; Golub, L.; Judge, P. G.; Landi, E.; McIntosh, S. W.; Reeves, K.; Seaton, D. B.; Zhang, J. Bibcode: 2019AGUFMSH11C3395G Altcode: Space-weather forecast capability is held back by our current lack of basic scientific understanding of CME magnetic evolution, and the coronal magnetism that structures and drives the solar wind. Comprehensive observations of the global magnetothermal environment of the solar atmosphere are needed for progress. When fully implemented, the COSMO suite of synoptic ground-based telescopes will provide the community with comprehensive and simultaneous measurements of magnetism, temperature, density and plasma flows and waves from the photosphere through the chromosphere and out into the corona. We will discuss how these observations will uniquely address a set of science objectives that are central to the field of solar and space physics: in particular, to understand the storage and release of magnetic energy, to understand CME dynamics and consequences for shocks, to determine the role of waves in solar atmospheric heating and solar wind acceleration, to understand how the coronal magnetic field relates to the solar dynamo, and to constrain and improve space-weather forecast models. Title: Convolutional Neural Networks for Predicting The Impact of Interplanetary Coronal Mass Ejections on The Near-Earth Magnetic Field Authors: Flyer, N.; Malanushenko, A. V.; Gibson, S. E. Bibcode: 2019AGUFMSH34B..07F Altcode: We present a convolutional neural network (CNN) for predicting the maximal amplitude of southward component of the near-Earth magnetic field near from a passing interplanetary coronal mass ejection (iCME). The input to the CNN is the Gibson & Low (GLOW) flux rope model (1998) that describes the coronal properties of a CME, where its morphology and position are controlled by 6 parameters. Our ultimate goal is to assess the ability of using a CNN architecture (2D or 3D) as an emulator of the physical processes operating on the CME between the Sun and Earth. The GLOW model is used as a first, simple test of a self-similarly expanding flux rope. It is the input to numerical simulations of CMEs propagating in the solar wind, in particular APL's Gamera code which uses GLOW as an input. The CNN problem is set up in two phases: 1) given input data near Sun, sets of three 2D images in the meridional plane, of the components magnetic field B: Bx, By, Bz, predict the maximal southward amplitude of the measured Bz at the Earth; 2) given line-of-sight integrated images of the Stokes parameters, U/I, V/I, Q/I, corresponding to the physical configuration in part 1, predict the maximal southward amplitude of the measured Bz at the Earth. Results will be presented for these two different CNN configurations. Title: Solaris: A Case for a Solar Polar Mission Authors: Hassler, D.; Newmark, J. S.; Gibson, S. E. Bibcode: 2019AGUFMSH13B..02H Altcode: Solar and Heliospheric physics has experienced a golden age of discovery over the past 20+ years, and the launches of Parker Solar Probe and Solar Orbiter promise to add exciting new observations and insights into our understanding of the Sun-Heliosphere system. So what is next? Although these missions have, and promise to continue to, revolutionize our understanding of the Sun, the one region that is still unexplored is the solar pole…the solar pole is one of the final frontiers of solar physics.

Solaris is a solar polar mission concept to address some of the fundamental questions that can only be answered from a polar vantage point. Solaris will obtain continuous, high latitude (>55 deg.) observations of the solar poles for multiple solar rotations, providing the continuity necessary to detect sub-surface flows and follow the evolution of solar transient activity. The Solaris mission will be able to obtain sustained coverage of the solar interior and atmosphere from high latitudes, providing a unique and comprehensive investigation of the global Sun and heliosphere.

This talk will discuss some of these questions and scientific drivers for a solar polar mission, such as Solaris, and the requirements these scientific objectives place on the observational and orbital requirements of the mission. Title: Spectral Properties and Heavy Ion Abundances of Energetic Particles in SEP and CIR events observed during the first two Parker Solar Probe Orbits Authors: Desai, M. I.; Giacalone, J.; Mitchell, D. G.; Szalay, J. R.; Allen, R. C.; Hill, M. E.; McComas, D. J.; Christian, E. R.; Schwadron, N.; McNutt, R. L., Jr.; Wiedenbeck, M. E.; Joyce, C.; Cohen, C.; Cummings, A. C.; Davis, A.; Krimigis, S. M.; Leske, R. A.; Matthaeus, W. H.; Mewaldt, R. A.; Roelof, E. C.; Labrador, A. W.; Stone, E. C.; Gibson, S. E.; DeForest, C. Bibcode: 2019AGUFMSH22A..06D Altcode: NASA's Parker Solar Probe (PSP), successfully launched on August 12 2018, has completed its first two orbits around our Sun. With perihelia ~35 Rs for both encounters, PSP has made the closest-ever observations of the solar wind plasma, electromagnetic fields, and energetic particle environment in the inner heliosphere. The Energetic Particle Instruments (EPI) of the Integrated Science Investigation of the Sun (ISOIS) suite observed a number of solar energetic particle (SEP) events associated with flaring regions on the Sun, coronal mass ejections-driven shocks, and local compression regions, as well as particle events associated with corotating or stream interaction regions. This talk surveys the spectral properties and abundances of ~0.1-2 MeV/nucleon suprathermal H-Fe nuclei during these events and compares them with prior observations of their counterparts observed at 1 AU. We discuss these new PSP results in the context of our current understanding of the origin and acceleration of suprathermal ions, the acceleration of SEPs, and on the nature of particle transport inside Earth orbit. Finally, we discuss the implications of these results for existing theoretical models of the origin of suprathermal tails, and of the acceleration and transport of SEPs and CIR-associated energetic particle events. Title: The PUNCH Bowl: Data System and Data Products for NASA's PUNCH Mission Authors: Thompson, B. J.; DeForest, C.; Gibson, S. E. Bibcode: 2019AGUFMSA11C3231T Altcode: The Polarimeter to UNify the Corona and Heliosphere (PUNCH) mission requires a flexible data system because the anticipated user base will be using the data to tackle a wide range of science problems. Some will be using PUNCH data in the classic "imager" context, while others will be accessing the data to study solar wind dynamics.

The PUNCH Bowl provide PUNCH data, metadata, analysis tools, and higher-level PUNCH data products, which are derived from heliospheric images to provide additional information about structure and motion. Additionally, the PUNCH Bowl is your access point for PUNCH Recipes: all of the tools, code and routines that optimize the use of PUNCH data and streamline your access. By running the "recipes" users can easily trace and reproduce the steps used by others with minimal effort. The PUNCH Bowl is maintained and supported by the PUNCH science team, but welcomes contributions from users to ensure that everyone is able to easily access all available tools and methods. Title: Primary and Secondary Solar Polar Crown PILs over Five Solar Cycles Authors: Emery, B. A.; Webb, D. F.; Gibson, S. E.; Hewins, I. M.; McFadden, R.; Kuchar, T. A. Bibcode: 2019AGUFMSH13B..08E Altcode: Solar filaments are located on polarity inversion lines (PILs) on the sun. Polar crown filaments are found at high helio-latitudes, but usually encircle the Sun for a brief period prior to the polarity reversal around solar maximum. Usually, there are polar crown gaps in both hemispheres, where coronal holes extend from the polar regions to lower latitudes. We undertake a five solar-cycle (SC19-23) study of the high latitude polar crown PILs that encircle the sun each solar cycle using the McIntosh Archive. The McIntosh Archive consists of a set of hand-drawn solar synoptic (Carrington) maps created by Patrick McIntosh from 1964 to 2009 (SC20-23) using H-alpha images and magnetograms for PILs, and He-I 10830A images for coronal holes since 1974. Most of these maps have now been digitized, with some gaps in SC20 and SC21. We also digitized the Carrington maps created from Kodaikanal Solar Observatory data in India by Makarov and Sivaraman (1986) to extend the study back through SC19. We focus on the large unipolar magnetic cells which are prominent on the sun after sunspot minimum, and then the 'rush-to-the-poles' in the ascending part of the solar cycle before the polarity reverses in the polar regions. PILs form at the boundaries of the opposite-polarity cells. The primary polar crown PIL is at the highest latitudes, but a secondary polar crown PIL becomes visible during the 'rush-to-the-poles' (McIntosh, 2003). The secondary PIL lies about 10 degrees or more equatorward of the primary PIL, which disappears at high latitudes while the secondary PIL becomes the primary PIL around 55 degrees north and south. We look at the evolution of the maximum latitude of these primary and secondary PILs as well as their median locations. We calculate the slope of the 'rush-to-the-poles', and we see what the hemispherical differences are and between solar cycles. Our results on the two polar crown PILs inform us about the solar dynamo activity in the interior of the sun and help constrain dynamo models. Title: WHPI Hα "McIntosh" Carrington Maps Authors: Hewins, I. M.; Gibson, S. E.; Webb, D. F.; Kuchar, T. A.; McFadden, R.; Emery, B. A. Bibcode: 2019AGUFMSH41D3346H Altcode: In support of the Whole Heliosphere and Planetary Interactions (WHPI) effort and to highlight solar structure near solar minimum we will create synoptic maps of solar magnetic features. In particular, we will utilize Hα, EUV and photospheric magnetic field to represent filaments, filament channels, and the large scale distribution of the dominant magnetic polarity. These maps, done in the manner established by Patrick McIntosh, enable studies how such solar features relate to structures in the solar wind and in the space environment of the earth and other planets. Patrick McIntosh contributed three maps to the initial Whole Sun Months (WSM; 1996), and Robert McFadden, McIntosh's primary cartographer for Solar Cycle 23, similarly contributed three maps to the Whole heliospheric Interval (WHI; 2008). Hewins, trained by McIntosh and McFadden, will focus on CR2215 which represents the WHPI campaign: "Recurrent Coronal Holes/High Speed Solar Wind Streams", and CR2219 which is the WHPI campaign: "Total Solar Eclipse Campaign". Title: Polarimeter to UNify the Corona and Heliosphere (PUNCH): Imaging the Corona and Solar Wind as a Single System Authors: DeForest, C. E.; Gibson, S. E.; Beasley, M.; Colaninno, R. C.; Killough, R.; Kosmann, W.; Laurent, G. T.; McMullin, D. R. Bibcode: 2019AGUFMSH43B..06D Altcode: The Polarimeter to UNify the Corona and Heliosphere (PUNCH) is a Small Explorer mission from NASA, to understand the solar corona and young solar wind as a complete system. It comprises four matched cameras all operating as a "virtual instrument" to image Thomson-scattered light, from the vantage of four separate spacecraft in Sun-synchronous LEO. PUNCH is the first coronal and solar wind imager designed specifically to produce three dimensional images from a single vantage point. In addition, it will produce routine, several-times-per-day maps of solar wind flow throughout the outer corona and inner heliosphere, based on motion analysis of the image stream. Estimated launch date is early 2023 for a two-year nominal mission. We present a brief overview of the mission with emphasis on novel techniques used and exploited by the PUNCH mission, and novel analyses enabled for the science community by PUNCH. Title: Thermal Properties of Coronal Cavities Authors: Ba̧k-Stȩślicka, Urszula; Gibson, Sarah E.; Stȩślicki, Marek Bibcode: 2019SoPh..294..164B Altcode: We have analyzed 33 cavities observed between 2012 and 2018, from solar activity maximum to minimum. For each cavity we applied a differential emission measure method to obtain both a temperature distribution and a value of the average temperature. We find that cavities are filled with material hotter than the surrounding streamer, with temperatures in the range of 1.67 - 2.15 MK. Differences between temperatures of cavities and surrounding streamers are in the range of 0.11 - 0.32 MK with an average value of 0.21 MK. We found that temperatures of both, cavities and streamers, vary as a function of different phases of solar activity. During solar maximum the structures are slightly hotter than those observed during solar minimum (1.85 - 2.15 MK vs. 1.67 - 1.88 MK for cavities and streamers, respectively). Title: Forward Modeling of a Pseudostreamer Authors: Karna, Nishu; Savcheva, Antonia; Dalmasse, Kévin; Gibson, Sarah; Tassev, Svetlin; de Toma, Giuliana; DeLuca, Edward E. Bibcode: 2019ApJ...883...74K Altcode: In this paper, we present an analysis of a pseudostreamer embedding a filament cavity, observed on 2015 April 18 on the solar southwest limb. We use the flux-rope insertion method to construct nonlinear force-free field (NLFFF) models constrained by observed Solar Dynamics Observatory (SDO)/AIA coronal structures and the SDO/Helioseismic Magnetic Imager photospheric magnetogram. The resulting magnetic field models are forward-modeled to produce synthetic data directly comparable to Mauna Loa Solar Observatory/Coronal Multichannel Polarimeter (CoMP) observations of the intensity and linear polarization of the Fe XIII 1074.7 nm infrared coronal emission line using FORWARD. In addition, we determine the location of quasi-separatrix layers in the magnetic models, producing a Q-map from which the signatures of magnetic null points and separatrices can be identified. An apparent magnetic null observed in linear polarization by CoMP is reproduced by the model and appears in the region of the 2D-projected magnetic null in the Q-map. Further, we find that the height of the CoMP null is better reproduced by our NLFFF model than by the synthetic data we produce with potential-field source-surface models, implying the presence of a flux rope in the northern lobe of the pseudostreamer. Title: Simulating the Solar Corona in the Forbidden and Permitted Lines with Forward Modeling. I. Saturated and Unsaturated Hanle Regimes Authors: Zhao, Jie; Gibson, Sarah E.; Fineschi, Silvano; Susino, Roberto; Casini, Roberto; Li, Hui; Gan, Weiqun Bibcode: 2019ApJ...883...55Z Altcode: The magnetic field in the corona is important for understanding solar activity. Linear polarization measurements in forbidden lines in the visible/IR provide information about coronal magnetic direction and topology. However, these measurements do not provide a constraint on coronal magnetic field strength. The unsaturated, or critical regime of the magnetic Hanle effect is potentially observable in permitted lines for example in the UV, and would provide an important new constraint on the coronal magnetic field. In this paper we present the first side-by-side comparison of forbidden versus permitted linear polarization signatures, examining the transition from the unsaturated to the saturated regime. In addition, we use an analytic 3D flux rope model to demonstrate the Hanle effect for the line-of-sight versus plane-of-sky (POS) components of the magnetic field. As expected, the linear polarization in the unsaturated regime will vary monotonically with increasing magnetic field strength for regions where the magnetic field is along the observer’s line of sight. The POS component of the field produces a linear polarization signature that varies with both the field strength and direction in the unsaturated regime. Once the magnetic field is strong enough that the effect is saturated, the resulting linear polarization signal is essentially the same for the forbidden and permitted lines. We consider how such observations might be used together in the future to diagnose the coronal magnetic field. Title: Investigating Coronal Magnetism with COSMO: Science on the Critical Path To Understanding The ``Weather'' of Stars and Stellarspheres Authors: McIntosh, Scott; Tomczyk, Steven; Gibson, Sarah E.; Burkepile, Joan; de Wijn, Alfred; Fan, Yuhong; deToma, Giuliana; Casini, Roberto; Landi, Enrico; Zhang, Jie; DeLuca, Edward E.; Reeves, Katharine K.; Golub, Leon; Raymond, John; Seaton, Daniel B.; Lin, Haosheng Bibcode: 2019BAAS...51g.165M Altcode: 2019astro2020U.165M The Coronal Solar Magnetism Observatory (COSMO) is a unique ground-based facility designed to address the shortfall in our capability to measure magnetic fields in the solar corona. Title: Spectropolarimetric diagnostics of coronal magnetic field from UV and visible/IR during solar minimum Authors: Zhao, Jie; Gibson, Sarah; Fineschi, Silvano; Susino, Roberto Bibcode: 2019AAS...23430212Z Altcode: The invisible magnetic field in the corona plays an important role for solar activity, hence measuring the coronal magnetic field is highly desired. The linear polarization measurements in the saturated Hanle regime of visible/IR are already obtained by the CoMP telescope providing information about coronal magnetic direction and topology. Other observations such as linear polarization in UV unsaturated Hanle measurements provide important complementary information about the strength of 3D coronal field. Until such observations are available, we turn to the FORWARD model (Gibson et al. 2016) to explore how these polarization data might be used together to interpret the coronal magnetic field. As a physical state to input into FORWARD, the analytic magnetic model in this work is adopted from Gibson et al.(1996), which is an axisymmetric model and gives a potential field with an exception at the boundary of the helmet streamer where current sheets are added between the open and closed fields. The plasma model is adopted from Sittler&Guhathakurta (1999) and Vásquez et al. (2003), which is consistent with multi-observations. Given this model input of a 3D distribution of magnetic field and plasma for solar minimum, we obtain simulated polarization results in UV and visible/IR wavelengths. This allows us to consider how such observations might be used together in future to diagnose the coronal magnetic field. Title: Data-optimized Coronal Field Model. I. Proof of Concept Authors: Dalmasse, K.; Savcheva, A.; Gibson, S. E.; Fan, Y.; Nychka, D. W.; Flyer, N.; Mathews, N.; DeLuca, E. E. Bibcode: 2019ApJ...877..111D Altcode: 2019arXiv190406308D Deriving the strength and direction of the three-dimensional (3D) magnetic field in the solar atmosphere is fundamental for understanding its dynamics. Volume information on the magnetic field mostly relies on coupling 3D reconstruction methods with photospheric and/or chromospheric surface vector magnetic fields. Infrared coronal polarimetry could provide additional information to better constrain magnetic field reconstructions. However, combining such data with reconstruction methods is challenging, e.g., because of the optical thinness of the solar corona and the lack and limitations of stereoscopic polarimetry. To address these issues, we introduce the data-optimized coronal field model (DOCFM) framework, a model-data fitting approach that combines a parameterized 3D generative model, e.g., a magnetic field extrapolation or a magnetohydrodynamic model, with forward modeling of coronal data. We test it with a parameterized flux-rope insertion method and infrared coronal polarimetry where synthetic observations are created from a known “ground-truth” physical state. We show that this framework allows us to accurately retrieve the ground-truth 3D magnetic field of a set of force-free field solutions from the flux-rope insertion method. In observational studies, the DOCFM will provide a means to force the solutions derived with different reconstruction methods to satisfy additional common coronal constraints. The DOCFM framework therefore opens new perspectives for the exploitation of coronal polarimetry in magnetic field reconstructions and for developing new techniques to more reliably infer the 3D magnetic fields that trigger solar flares and coronal mass ejections. Title: MHD modeling of evolving ICME magnetic structure in the inner heliosphere Authors: Provornikova, Elena; Merkin, Vyacheslav; Malanushenko, Anna; Gibson, Sarah; Arge, Nick; Vourlidas, Angelos Bibcode: 2019shin.confE.230P Altcode: As CME propagates through the inner heliosphere, evolution of its structure is influenced by the interaction with the solar wind streams. I will present our recent simulations with GAMERA code of propagating flux rope-CME from 0.1 to 1 AU in the background solar wind. We evaluate self-similarly an erupting CME at 0.1 AU based on the Gibson-Low model and insert it into our global inner heliosphere model driven by the Wang-Sheeley-Arge (WSA) model of the corona, while WSA, in turn, is driven by ADAPT global photospheric magnetic field maps. To simulate the ICME propagation in the inner heliosphere, we use the GAMERA (Grid Agnostic MHD for Extended Research Applications) magnetohydrodynamic (MHD) code which is a reinvention of the high-heritage Lyon-Fedder-Mobarry (LFM) code. We present modeling results and focus on the evolution of the large-scale structure of the CME from the outer solar corona to Earth. In particular I will present a simulation of the April 3, 2010 CME event. Title: Historical astronomical data: urgent need for preservation, digitization enabling scientific exploration Authors: Pevtsov, Alexei; Griffin, Elizabeth; Grindlay, Jonathan; Kafka, Stella; Bartlett, Jennifer; Usoskin, Ilya; Mursula, Kalevi; Gibson, Sarah; Pillet, Valentín; Burkepile, Joan; Webb, David; Clette, Frédéric; Hesser, James; Stetson, Peter; Muñoz-Jaramillo, Andres; Hill, Frank; Bogart, Rick; Osborn, Wayne; Longcope, Dana Bibcode: 2019BAAS...51c.190P Altcode: 2019arXiv190304839P; 2019astro2020T.190P This white paper emphasizes critical importance of preservation, digitization and scientific exploration of historical astronomical data. It outlines the rationale, provides examples of new science with such data, and reviews the potential losses to science if nothing it done. Title: Coronal Mass Ejections from Sun to Earth: Recent Advances in Modeling and Statistical Approaches Authors: Malanushenko, Anna; Gibson, S.; Dalmasse, K.; Merkin, V.; Provornikova, E.; Vourlidas, A.; Arge, C.; Nychka, D.; Wiltberger, M.; Flyer, N. Bibcode: 2019shin.confE.206M Altcode: Solar coronal mass ejections (CMEs) are violent eruptive phenomena which originate on the Sun; their heliospheric extensions, called interplanetary CMEs, are known for their potential to impact the whole heliosphere and, in particular, the Earth. While not all CMEs are launched in such a way as to hit the Earth, those that do can have big impacts on Earth's magnetosphere. The magnitude of such impact depends upon many factors such as the CME launch location and velocity, its positioning within the background solar wind, its mass, and its magnetic properties such as the orientation of its front with respect to the Earth's magnetic field.

Case studies of how iCMEs propagate through the heliosphere are complicated by many factors, including often incomplete input for models. We present and discuss a different approach. Rather than focusing on modeling a particular event, we intend to carry out a large statistical study in the event parameter space. Further, Bayesian statistics will be used along with large statistical databases of near-Sun and near-Earth observables, to infer statistical distributions of relevant CME input parameters, which are capable of yielding given distributions of observables, for a given stage of the the solar cycle.

We use a analytical flux rope model (Gibson&Low model) and a background solar wind boundary (Wang-Sheeley-Arge model) as inputs for a new MHD heliospheric simulation code (Gamera). We give an overview and update of the project and show first modeling results. Title: COSMO Science Authors: Gibson, Sarah; Tomczyk, Steven; Burkepile, Joan; Casini, Roberto; Deluca, Ed; de Toma, Giuliana; deWijn, Alfred; Fan, Yuhong; Golub, Leon; Judge, Philip; Landi, Enrico; Lin, Haosheng; McIntosh, Scott; Reeves, Kathy; Seaton, Dan; Zhang, Jie Bibcode: 2019shin.confE..32G Altcode: Space-weather forecast capability is held back by our current lack of basic scientific understanding of CME magnetic evolution, and the coronal magnetism that structures and drives the solar wind. Comprehensive observations of the global magnetothermal environment of the solar atmosphere are needed for progress. When fully implemented, the COSMO suite of synoptic ground-based telescopes will provide the community with comprehensive and simultaneous measurements of magnetism, temperature, density and plasma flows and waves from the photosphere through the chromosphere and out into the corona. We will discuss how these observations will uniquely address a set of science objectives that are central to the field of solar and space physics: in particular, to understand the storage and release of magnetic energy, to understand CME dynamics and consequences for shocks, to determine the role of waves in solar atmospheric heating and solar wind acceleration, to understand how the coronal magnetic field relates to the solar dynamo, and to constrain and improve space-weather forecast models. Title: MHD simulation of prominence-cavity system and forward modeling of COSMO/LC line-of-sight magnetic field measurement Authors: Fan, Yuhong; Liu, Tie; Gibson, Sarah Bibcode: 2019shin.confE..70F Altcode: We present magnetohydrodynamic simulation of the evolution from quasi-equilibrium to onset of eruption of a twisted, prominence-forming coronal magnetic flux rope underlying a corona streamer. The flux rope is built up by an imposed flux emergence at the lower boundary. During the quasi-static phase of the evolution, we find the formation of a prominence-cavity system with qualitative features resembling observations, as shown by the synthetic SDO/AIA EUV images with the flux rope observed above the limb viewed nearly along its axis. The cavity contains substructures including “U”-shaped or horn-liked features extending from the prominence enclosing a central “cavity” on top of the prominence. The prominence condensations form in the dips of the highly twisted field lines due to runaway radiative cooling and the cavity is formed by the density depleted portions of the prominence-carrying field lines extending up from the dips. The flux rope eventually erupts as its central part rises quasi-statically to a critical height, producing a CME with associated prominence eruption. Using the MHD model of the prominence-cavity system, we carry out forward synthesis of the circular polarization signal of the Fe XIII emission line at 1074.7 nm as would be measured by the proposed COronal Solar Magnetism Observatory (COSMO) Large Coronagraph (LC) and infer the line-of-sight (LOS) magnetic field, with the simulated flux rope observed above the limb viewed linearly along its length. We find that the COSMO/LC can detect a significant LOS magnetic field from the flux rope with the measurement most sensitive to the region surrounding the prominence, i.e. the prominence horn region in the cavity. The measurement can detect an out-moving LOS field during the slow rise phase up to the onset of eruption. Title: Coronal Hole Lifetimes Studied with the McIntosh Archive Authors: Hewins, Ian; McFadden, Robert; Emery, Barbara; Gibson, Sarah; Webb, David; Kuchar, Thomas Bibcode: 2019shin.confE.188H Altcode: Through long term observation we can see that coronal holes positions and lifespans change dramatically over a solar cycle, but tend to repeat those patterns from solar cycle to solar cycle. By looking at the positions and lifespans of different coronal holes we can see that they are interconnected with the extended solar cycle (22yrs) and the activity cycle (11yrs). The positions of low latitude coronal holes that remain for over one rotation demonstrate a dramatic similarity to both sunspots and plage in terms of their positions on the sun over a solar cycle, forming the classic butterfly pattern. Title: Linear Polarization Observations of Coronal Pseudostreamers Authors: de Toma, Giuliana; Gibson, Sarah; Dalmasse, Kevin Bibcode: 2019shin.confE..27D Altcode: Pseudostreamers are common coronal structures that appear at the solar limb as streamers bordering regions of the same magnetic polarity. They are locations prone to sympathetic eruptions and sources of an hybrid kind of solar wind with properties intermediate between slow and moderately fast wind. The pseudostreamer magnetic topological skeleton, and in particular the magnetic X-point at their cusp, imprints a very clear signature in linear polarization that distinguish pseudostreamers from the larger helmet streamers or two nearby streamers. We use polarimetric data taken with the Coronal Multichannel Polarimeter (CoMP) at the Mauna Loa Solar Observatory from 2013 to 2017 to analyze pseudostreamers and compare them with PFSS models. The solarsoft software package FORWARD is used to derive from the models a synthetic linear polarization image that can be directly compared with the observations and to compute the magnetic field expansion factor from both observations and models. We find differences between observations and PFSS extrapolations. In particular, the height of the magnetic X-point is always higher in the observations, indicating that PFSS models systematically underestimate the height of the cusp null point and confirming the previous result of Gibson et al. in 2017 based on a single pseudostreamer on April 18 2015. Gibson et al. also noted that the expansion factor for the case they studied was significantly larger in CoMP observations than expected from a potential field extrapolation with possible implications for solar wind speed. Our statistical analysis shows this is not always the case. We find no clear trend in how the expansion factor derived from observations compares to models and, at least at the heights covered by the CoMP field-of-view (up to 1.35 solar radii), the observed expansion factor cannot be used as meaningful diagnostic for solar wind speed. Title: Major Scientific Challenges and Opportunities in Understanding Magnetic Reconnection and Related Explosive Phenomena throughout the Universe Authors: Ji, Hantao; Alt, A.; Antiochos, S.; Baalrud, S.; Bale, S.; Bellan, P. M.; Begelman, M.; Beresnyak, A.; Blackman, E. G.; Brennan, D.; Brown, M.; Buechner, J.; Burch, J.; Cassak, P.; Chen, L. -J.; Chen, Y.; Chien, A.; Craig, D.; Dahlin, J.; Daughton, W.; DeLuca, E.; Dong, C. F.; Dorfman, S.; Drake, J.; Ebrahimi, F.; Egedal, J.; Ergun, R.; Eyink, G.; Fan, Y.; Fiksel, G.; Forest, C.; Fox, W.; Froula, D.; Fujimoto, K.; Gao, L.; Genestreti, K.; Gibson, S.; Goldstein, M.; Guo, F.; Hesse, M.; Hoshino, M.; Hu, Q.; Huang, Y. -M.; Jara-Almonte, J.; Karimabadi, H.; Klimchuk, J.; Kunz, M.; Kusano, K.; Lazarian, A.; Le, A.; Li, H.; Li, X.; Lin, Y.; Linton, M.; Liu, Y. -H.; Liu, W.; Longcope, D.; Louriero, N.; Lu, Q. -M.; Ma, Z. -W.; Matthaeus, W. H.; Meyerhofer, D.; Mozer, F.; Munsat, T.; Murphy, N. A.; Nilson, P.; Ono, Y.; Opher, M.; Park, H.; Parker, S.; Petropoulou, M.; Phan, T.; Prager, S.; Rempel, M.; Ren, C.; Ren, Y.; Rosner, R.; Roytershteyn, V.; Sarff, J.; Savcheva, A.; Schaffner, D.; Schoeffier, K.; Scime, E.; Shay, M.; Sitnov, M.; Stanier, A.; TenBarge, J.; Tharp, T.; Uzdensky, D.; Vaivads, A.; Velli, M.; Vishniac, E.; Wang, H.; Werner, G.; Xiao, C.; Yamada, M.; Yokoyama, T.; Yoo, J.; Zenitani, S.; Zweibel, E. Bibcode: 2019BAAS...51c...5J Altcode: 2019astro2020T...5J This is a group white paper of 100 authors (each with explicit permission via email) from 51 institutions on the topic of magnetic reconnection which is relevant to 6 thematic areas. Grand challenges and research opportunities are described in observations, numerical modeling and laboratory experiments in the upcoming decade. Title: Measuring coronal magnetic fields associated with CMEs: UV spectropolarimetric study Authors: Zhao, Jie; Fan, Yuhong; Gibson, Sarah Bibcode: 2019shin.confE.144Z Altcode: Transformative progress into understanding the forces that drive CME eruption and evolution would arise from spectropolarimetric measurements of the magnetic fields in the CME and surrounding corona. Linear polarization measurements in the visible/IR already obtained by the Mauna Loa Solar Observatory CoMP telescope have established the power of coronal spectropolarimetry for diagnosing pre-eruption magnetic field direction and topology. Forward modeling has demonstrated the potential of future large visible/IR telescopes including DKIST and COSMO for quantifying the coronal magnetic field strength. In particular, recent work has shown that COSMO has sufficient aperture to track the core magnetic strength of the CME during eruption. We have now extended this analysis to the UV unsaturated Hanle regime, and will demonstrate how such novel measurements could provide critical new measurements to constrain the fundamental magnetic nature of the CME. Title: The Whole Heliosphere and Planetary Interactions (WHPI) Initiative Authors: Kolinski, Don; Gibson, Sarah; Thompson, Barbara; Bagenal, Fran; de Toma, Giuliana; McGranaghan, Ryan; DiBraccio, Gina Bibcode: 2019shin.confE.108K Altcode: The Whole Heliosphere and Planetary Interactions (WHPI) is a scientific initiative with hundreds of participants worldwide to coordinate observations and modeling of the solar-heliospheric-planetary system during solar minimum and to promote and facilitate inter-disciplinary activities. We do this by organizing observing campaigns and dedicated science workshops to bring scientists from different scientific fields together. The aim of WHPI is to better understand how the Sun’s output affects the heliosphere and planets. The simpler magnetic configuration of the Sun and the infrequency of CMEs make solar minimum an ideal time to make such connection. Science objectives of WHPI include: characterizing the 3D magnetic structure of the Sun and heliosphere during the current minimum, following the propagation and evolution of the Sun’s magnetic field through the solar wind and its interaction with the magnetospheres of the Earth and other planets, quantifying the effects of the solar radiative output the Earth and other planets, and investigating the effect of a deep and prolonged solar minimum on the entire heliosphere. With this poster, we invite the SHINE community to join the WHPI initiative. Title: The Turing Way: A Handbook for Reproducible Data Science Authors: Way Community, The Turing; Arnold, Becky; Bowler, Louise; Gibson, Sarah; Herterich, Patricia; Higman, Rosie; Krystalli, Anna; Morley, Alexander; O'Reilly, Martin; Whitaker, Kirstie Bibcode: 2019zndo...3233986W Altcode: Reproducible research is necessary to ensure that scientific work can be trusted. Funders and publishers are beginning to require that publications include access to the underlying data and the analysis code. The goal is to ensure that all results can be independently verified and built upon in future work. This is sometimes easier said than done. Sharing these research outputs means understanding data management, library sciences, software development, and continuous integration techniques: skills that are not widely taught or expected of academic researchers and data scientists. The Turing Way is a handbook to support students, their supervisors, funders and journal editors in ensuring that reproducible data science is "too easy not to do". It will include training material on version control, analysis testing, and open and transparent communication with future users, and build on Turing Institute case studies and workshops. This project is openly developed and any and all questions, comments and recommendations are welcome at our github repository: https://github.com/alan-turing-institute/the-turing-way. Release log v0.0.4: Continuous integration chapter merged to master. v0.0.3: Reproducible environments chapter merged to master. v0.0.2: Version control chapter merged to master. v0.0.1: Reproducibility chapter merged to master. Title: Origins of the Ambient Solar Wind: Implications for Space Weather Authors: Cranmer, Steven R.; Gibson, Sarah E.; Riley, Pete Bibcode: 2019sfsw.book...41C Altcode: No abstract at ADS Title: Beyond Flatland: A Star of Many Dimensions Authors: Gibson, Sarah Bibcode: 2018csc..confE..75G Altcode: The more we have learned about the Sun, the more we can appreciate its essential complexity. Telescopes confirmed that it was not an unblemished sphere. Multi-wavelength observations revealed its structured atmosphere, and ever-higher resolution exposed its spectacular dynamics. Helioseismology penetrated its depths, and STEREO views gave us our first three-dimensional perspective. With Solar Orbiter we will finally leave our ecliptic bias behind and see the Sun from high latitudes. What will we see? And what could we see if future missions dwell at near-polar vantages, providing a synoptic view from above or below? The science enabled by such viewpoints is broad and deep, with potential both to finally fill known gaps in our understanding, and to reveal hitherto undiscovered aspects of the Sun and heliosphere. Title: Solar prominences: theory and models. Fleshing out the magnetic skeleton Authors: Gibson, Sarah E. Bibcode: 2018LRSP...15....7G Altcode: Magnetic fields suspend the relatively cool material of solar prominences in an otherwise hot corona. A comprehensive understanding of solar prominences ultimately requires complex and dynamic models, constrained and validated by observations spanning the solar atmosphere. We obtain the core of this understanding from observations that give us information about the structure of the "magnetic skeleton" that supports and surrounds the prominence. Energetically-sophisticated magnetohydrodynamic simulations then add flesh and blood to the skeleton, demonstrating how a thermally varying plasma may pulse through to form the prominence, and how the plasma and magnetic fields dynamically interact. Title: The Eruption of a Prominence-carrying Coronal Flux Rope: Forward Synthesis of the Magnetic Field Strength Measurement by the COronal Solar Magnetism Observatory Large Coronagraph Authors: Fan, Yuhong; Gibson, Sarah; Tomczyk, Steve Bibcode: 2018ApJ...866...57F Altcode: 2018arXiv180806142F From a magnetohydrodynamic (MHD) simulation of the eruption of a prominence hosting coronal flux rope, we carry out forward synthesis of the circular polarization signal (Stokes V signal) of the Fe XIII emission line at 1074.7 nm produced by the MHD model as measured by the proposed COronal Solar Magnetism Observatory (COSMO) Large Coronagraph (LC) and infer the line-of-sight magnetic field, B LOS, above the limb. With an aperture of 150 cm, an integration time of 12 minutes, and a resolution of 12 arcsec, the LC can measure a significant B LOS with a sufficient signal-to-noise level, from the simulated flux rope viewed nearly along its axis with a peak axial field strength of about 10 G. The measured B LOS is found to relate well with the axial field strength of the flux rope for the height range of the prominence and can discern the increase with height of the magnetic field strength in that height range that is a definitive signature of the concave upturning dipped field supporting the prominence. The measurement can also detect an outward-moving B LOS due to the slow rise of the flux rope as it develops the kink instability, during the phase when its rise speed is still below about 41 km s-1 and up to a height of about 1.3 solar radii. These results suggest that the COSMO LC has great potential to provide quantitative information about the magnetic field structure of coronal mass ejection precursors (e.g., the prominence cavities) and their early evolution for the onset of eruption. Title: Solar Physics from Unconventional Viewpoints Authors: Gibson, Sarah E.; Vourlidas, Angelos; Hassler, Donald M.; Rachmeler, Laurel A.; Thompson, Michael J.; Newmark, Jeffrey; Velli, Marco; Title, Alan; McIntosh, Scott W. Bibcode: 2018FrASS...5...32G Altcode: 2018arXiv180509452G We explore new opportunities for solar physics that could be realized by future missions providing sustained observations from vantage points away from the Sun-Earth line. These include observations from the far side of the Sun, at high latitudes including over the solar poles, or from near-quadrature angles relative to the Earth (e.g., the Sun-Earth L4 and L5 Lagrangian points). Such observations fill known holes in our scientific understanding of the three-dimensional, time-evolving Sun and heliosphere, and have the potential to open new frontiers through discoveries enabled by novel viewpoints. Title: The Coronal Solar Magnetism Observatory Authors: Thompson, Michael J.; Tomczyk, Steven; Gibson, Sarah E.; McIntosh, Scott W.; Landi, Enrico Bibcode: 2018IAUS..335..359T Altcode: The Coronal Solar Magnetism Observatory (CoSMO) is a proposed new facility led by the High Altitude Observatory and a consortium of partners to measure magnetic field and plasma properties in a large (one degree) field of view extending down to the inner parts of the solar corona. CoSMO is intended as a research facility that will advance the understanding and prediction of space weather. The instrumentation elements of CoSMO are: a white-light coronagraph (KCor), already operational at the Mauna Loa Solar Observatory (MLSO); the Chromosphere and Prominence Magnetometer (ChroMag), due for deployment to MLSO next year; and the CoSMO Large Coronagraph (LC) which has completed Preliminary Design Review. Title: The eruption of a prominence carrying coronal flux rope: forward synthesis of the magnetic field strength measurement by the COronal Solar Magnetism Observatory Large Coronagraph Authors: Fan, Yuhong; Gibson, Sarah; Tomczyk, Steven Bibcode: 2018cosp...42E1038F Altcode: From a magnetohydrodynamic (MHD) simulation of the eruption of prominence hosting coronal flux rope, we carry out forward synthesis of the circular polarization signal V/I produced by the MHD model as measured by the proposed COronal Solar Magnetism Observatory (COSMO) Large Coronagraph (LC) and infer the line-of-sight magnetic field BLOS above the limb. With an aperture of 150 cm, integration time of 300 sec, and an observation pixel of 12 arcsec, the LC can measure a significant BLOS with sufficient signal to noise level, from the simulated flux rope with a peak azimuthal field strength of about 10 G. The measured BLOS is found to relate well with the axial field strength of the flux rope within the height range of the prominence, and can discern the increase with height of the magnetic field strength along the prominence that is a definitive signature of the concave upturning dipped field supporting the prominence. The measurement can also detect above the noise the outward rise of the BLOS due to the slow rise of the flux rope as it develops the kink instability, during the phase when its rise speed is still below 15 km/s and up to a height of about 1.25 solar radius. These results suggest that the COSMO LC has great potential in providing quantitative information about the magnetic field structure of CME precursors (such as prominences) and their early evolution for the onset of eruption. Title: "Building a Magnetic Skeleton of the Solar Corona: Towards Better 3-D Constraints on the Coronal Magnetic Field Authors: Malanushenko, Anna; Gibson, Sarah; Kucera, Therese; McKenzie, David Bibcode: 2018cosp...42E2139M Altcode: The energy stored in the solar magnetic field is what is powering many violent explosive events in the solar atmosphere, or the corona. Some of these events result in the coronal mass ejections (CME's) released into the interplanetary space. The magnetic field in the solar corona is therefore very important to know, yet it is very difficult to measure. Most of the time it is modeled with the magnetic maps at the solar surface used as boundary conditions. The magnetic maps on the surface are therefore also important to know, yet the full vector of the field on the surface is also difficult to measure. Once such measurements are made, constructing a model capable of predicting eruptive potential of a given region is on its own a complicated task. One of the problems arising is that that the equations for low-beta equilibria, which are often used to describe the coronal field, do not, strictly speaking, work for the solar surface. In short, we need better inputs to model the solar corona. The use of non-magnetic and non-surface constraints on the magnetic field becomes increasingly popular. For example, the paths of filaments can be used to guide flux rope trajectories; the loops of active regions, seen in extreme ultraviolet (EUV) can be used to obtain 3-D trajectories of magnetic field lines and estimate electric currents flowing along them. We are currently exploring ways to use other sources of data, such as flows in prominences and coronal spectropolarimetric data, in a similar fashion. I will talk about this work, and about our project of aggregating many different sources of non-magnetic 3-D constraints on the magnetic field. The resulting 'skeleton' can be used to constraint global field models, or to validate models obtained in traditional ways. We intend to develop a pipeline and assemble several skeletons for several instances in time of the Sun, which we will then release to community. Title: Tracing the Origins of the Solar Wind by Tracking Flows and Disturbances in Coronagraph Data Authors: Thompson, Barbara J.; Attie, Raphael; DeForest, Craig E.; Gibson, Sarah E.; Hess Webber, Shea A.; Ireland, Jack; Kirk, Michael S. F.; Kwon, Ryun Young; McGranaghan, Ryan; Viall, Nicholeen M. Bibcode: 2018shin.confE..47T Altcode: The challenge of identifying transient motions in solar imagery has been addressed in a number of ways. A variety of methods have been developed to detect and characterize the motion and extent of coronal mass ejections, for example. We discuss the adaptation of CME and solar transient detection methods to trace smaller-scale perturbations consistent with solar wind motions in the inner heliosphere (out to 10 RSun). We evaluate several methods, and compare the speed and structure results to model predictions. In particular, we discuss how high-cadence heliospheric imagery can be used to track small scale solar density variations throughout the solar wind, serving as a proxy for in situ velocity detection, but with global and continuous coverage. Title: Magnetic field measurements in the solar corona: facing the challenge with ground and space based observations Authors: Bemporad, Alessandro; Fineschi, Silvano; Mancuso, Salvatore; Gibson, Sarah; Susino, Roberto; Massone, . Giuseppe; Capobianco, Gerardo; Frassati, Federica Bibcode: 2018cosp...42E.265B Altcode: Actual limitations in understanding physical processes occurring in the solar atmosphere are related with our poor capabilities in measuring magnetic fields in its layers. The knowledge of magnetic fields in the solar corona is crucial to understand the origin of solar flares and Coronal Mass Ejections, waves, coronal heating and solar wind acceleration. For these reasons many different techniques have been proposed to provide these measurements by analysing the emission related with many different physical phenomena (e.g.: radio observations of gyrosynchrotron and free-free emission, infrared observations of Zeeman effect, visible and infrared obervations of the Hanle effect, UV-EUV observations of CME-driven shock waves, etc..). In order to provide a continuous monitoring of coronal fields, new ground- and space-based instrumentations are currently under development, as well as new techniques to infer the real fields from the line-of-sight integrated coronal emission. At the same time, the forward modelling of the expected emission starting from different possible coronal field configurations is being developed, allowing the definition of the required properties for future instrumentation and the verification of the data analysis results. Title: Pseudostreamer topology revealed by CoMP observations Authors: De Toma, Giuliana; Gibson, Sarah; Dalmasse, Kévin; Miralles, Mari Paz Bibcode: 2018cosp...42E.787D Altcode: Pseudostreamers represent sources of the solar wind whose properties are a subject of active investigation. Their magnetic structure, and particularly the expansion of magnetic flux tubes associated with them, is a matter of current debate. Pseudostreamers are associated with magnetic nulls, which are known to be locations prone to magnetic reconnection that potentially facilitate eruptions. A recent study demonstrated the novel constraints on pseudostreamer topology provided by coronal spectropolarimetry, in particular linear polarization measured by the Coronal Muiltichannel Polarimeter (CoMP) telescope at the Mauna Loa Solar Observatory. That study for the first time provided a method for determining magnetic expansion in the corona independent from any extrapolation or global MHD model representation of the coronal field. It found that this expansion factor was larger and the magnetic null was higher for a pseudostreamer observed by CoMP than expected from a potential field calculation. In this work we extend our analysis to additional observations of pseudostreamers made by CoMP, for which we identify the magnetic nulls and quantify expansion factor. Our goal is to understand if there are systematic differences between these observations and predictions of a potential field model. Title: Global Solar Magnetic Field Evolution Over 4 Solar Cycles: Use of the McIntosh Archive Authors: Webb, David F.; Gibson, Sarah E.; Hewins, Ian M.; McFadden, Robert H.; Emery, Barbara A.; Malanushenko, Anna; Kuchar, Thomas A. Bibcode: 2018FrASS...5...23W Altcode: The McIntosh Archive consists of a set of hand-drawn solar Carrington maps created by Patrick McIntosh from 1964 to 2009. McIntosh used mainly Hα, He-I 10830Å and photospheric magnetic measurements from both ground-based and NASA satellite observations. With these he traced polarity inversion lines (PILs), filaments, sunspots and plage and, later, coronal holes over a 45-year period. This yielded a unique record of synoptic maps of features associated with the large-scale solar magnetic field over four complete solar cycles. We first discuss how these and similar maps have been used in the past to investigate long-term solar variability. Then we describe our work in preserving and digitizing this archive, developing a digital, searchable format, and creating a website and an archival repository at NOAA's National Centers for Environmental Information (NCEI). Next we show examples of how the data base can be utilized for scientific applications. Finally, we present some preliminary results on the solar-cycle evolution of the solar magnetic field, including the polar field reversal process, the evolution of active longitudes, and the role of differential solar rotation. Title: Linear Line-Polarimetry: probing the magnetic field mechanisms of energy deposition in corona. Authors: Fineschi, Silvano; Gibson, Sarah; Susino, Roberto; Zhao, Jie Bibcode: 2018cosp...42E1073F Altcode: Optically-thin, UV spectral lines in corona are linearly polarized by resonance scattering of chromospheric line-emissions off coronal ions.In the presence of coronal magnetic fields, the resontantly-scattered line-polarization is modified by the Hanle effect. Spectro-polarimetric UV observations from space of these line-emissions, interpreted in terms of the Hanle effects, are a powerful tool for the diagnostics of magnetic fields in the solar chromosphere/corona.Through the anisotropic Doppler-dimmng effect, the linear polarization of optically thin spectral lines is sensitive to anisotropic ion-velocity distributions that can be induced by the ion-cyclotron resonance between plasmas and MHD waves in corona. This effect is believed to influence some heavy ions in the solar corona. Thus, coronal polarimetry of resonantly scattered UV spectral lines can also serve as a powerful tool for probing the magnetic field mechanism(s) of energy deposition in corona.This presentation reports the parameter study carried out by forward modeling of the linear polarization of the coronal UV spectral lines HI Lyman-α, 121.6 nm, and OVI, 103.2 nm. The study was based on the FORWARD numerical code developed by the High Altitude Observatory. The study used FORWARD to reproduce synthetic linear line-polarization maps for different MHD models of the corona.The results from the parameters study indicate that the Hanle effect diagnostics is most effective within a few tens of solar radii from the solar limb in closed-field, active regions where the strength the coronal magnetic field is within the Hanle effect sensitivity for the HI Lyman-α and OVI lines (i.e., 2-60 gauss). On the other hand, the effect of anisotropic velocity field distributions of scattering ions on the line-polarization emitted by resonance scattering is most effective in open-filed regions of non-radial solar wind, such as the interface coronal holes-streamers. Title: A Space Coronal Magnetometry Mission Authors: Lin, Haosheng; Gibson, Sarah; Savage, Sabrina; Tomczyk, Steven; Downs, Cooper; Rachmeler, Laurel; Kramar, Maxim; Habbal, Shadia Bibcode: 2018cosp...42E2020L Altcode: Direct measurement of the polarized spectra of forbidden coronal emission lines (CELs) is the most powerful tool for the study of the solar coronal magnetic fields. Due to its low optical density, simultaneous multi-sight-lines observations of the corona from space are needed for tomographic inversion to disentangle the 3D structure of the solar corona. This presentation will describe the mission concept and instrument design of a future space coronal magnetometry mission, consists of many clusters of small spacecraft in near-sun heliocentric orbits to observe the sun to enable tomographic determination of the 3D magnetic and thermodynamic structures of the corona. The spacecraft will be equipped with a wide field, super achromatic lens coronagraph equipped with two 100-slit, 4-channel spectropolarimeters optimized for measurement of the polarized CEL spectra from space. This instrument is tentatively named 'mxCSM'- the massively-multiplexed Coronal SpectroMagnetometer. A prototype mxCSM is currently under construction with funding from a 2017 National Science Foundation Major Research Instrument program grant. This space coronal space magnetometry mission will advance our knowledge of the corona and the physics of energetic coronal eruptions, and ultimately enable accurate space weather forecast. Title: Simulating the solar minimum corona in UV and visible/IR wavelengths with forward modeling Authors: Zhao, Jie; Fineschi, Silvano; Gibson, Sarah; Susino, Roberto Bibcode: 2018cosp...42E3853Z Altcode: The magnetic field in the corona is important for understanding solar activity, but is difficult to measure due to the tenuous plasma. Therefore many alternative methods have been adopted to get the 3D magnetic field in the corona, such as extrapolation methods relying on the photospheric magnetograms. Such extrapolations make problematic assumptions about the force-free nature of the photosphere, and are highly sensitive to uncertainties in the photosphere magnetic measurements. Measuring the coronal magnetic field directly is thus to be desired, and linear polarization measurements in the visible/IR are already obtained by the CoMP telescope providing information about coronal magnetic direction and topology. However other observations such as circlar polarization in the visible/IR and UV unsaturated Hanle measurements are needed to better observe the 3D coronal field. Until such observations are available, we turn to the FORWARD model (Gibson et al. 2016) which simulates all of these polarization data. As a physical state to input into FORWARD, the analytic magnetic model in this work is adopted from Gibson et al.(1996), which gives a potential field with an exception at the boundary of the helmet streamer where current sheets are added between the open and closed fields. This analytic model has the benifit of matching white light and also photospheric magnetic flux observations at solar minimum. Given this model input of a 3D distribution of magnetic field and plasma, we obtain simulated polarization results in UV and visible/IR wavelengths. This allows us to consider how such observations might be used together in future to diagnose the coronal magnetic field. Title: Solar Observations Away from the Sun-Earth Line Authors: Gibson, Sarah E.; McIntosh, Scott William; Rachmeler, Laurel; Thompson, Michael J.; Title, Alan M.; Velli, Marco C. M.; Vourlidas, Angelos Bibcode: 2018tess.conf40340G Altcode: Observations from satellite missions have transformed the field of solar physics. High-resolution observations with near-continuous temporal coverage have greatly extended our capability for studying long-term and transient phenomena, and the opening of new regions of the solar spectrum has made detailed investigation of the solar atmosphere possible.

However, to date most solar space-based missions have been restricted to an observational vantage in the vicinity of the Sun-Earth line, either in orbit around the Earth or from the L1 Lagrangian point. As a result, observations from these satellites represent the same geometrical view of the Sun that is accessible from the Earth.

Understanding the deep interior structure of the Sun and the full development of solar activity would really benefit from fully three-dimensional monitoring of the solar atmosphere and heliosphere. On the one hand, simultaneous spacecraft observations from multiple vantage points would allow studies of the deep interior structure of the sun via stereoscopic helioseismology; on the other, distributed observations would allow the understanding of the complete evolution of activity complexes and enhance space weather predictions dramatically.

Presently, observations of the Sun away from Earth are obtained by the STEREO pair of satellites, which have provided an unprecedented global view by orbiting around to the far side of the Sun, and the Ulysses mission, which achieved a high-inclination (80˚) near-polar orbit (but which, however, did not include any solar imaging instruments). The forthcoming Solar Orbiter mission, which will orbit the sun and reach a maximum inclination of 34˚ out of the ecliptic should provide the first detailed mapping of the sun's polar fields. In addition, Solar Probe Plus will explore the outer corona and inner Heliosphere with very rapid solar encounters at a minimum perihelion 9.86 solar radii from the center of the Sun.

We explore some of the new opportunities for solar physics that can be realized by future missions that provide sustained observations from vantage points away from the Sun-Earth line (and in some cases the ecliptic plane): observations from the far side of the Sun, over its poles, or from the L5 Lagrangian point. Title: Tracking Flows and Disturbances in Coronagraph Data Authors: Thompson, Barbara J.; Attie, Raphael; DeForest, Craig E.; Gibson, Sarah E.; Hess Webber, Shea A.; Inglis, Anfew R.; Ireland, Jack; Kirk, Michael S.; Kwon, RyunYoung; Viall, Nicholeen M. Bibcode: 2018tess.conf30922T Altcode: The challenge of identifying transient motions in solar imagery has been addressed in a number of ways. A variety of methods have been developed to detect and characterize the motion and extent of coronal mass ejections, for example. We discuss the adaptation of CME and solar transient detection methods to trace smaller-scale perturbations consistent with solar wind motions in the inner heliosphere (over 10 RSun). We evaluate several methods, and compare the speed and structure results to model predictions. In particular, we discuss how high-cadence heliospheric imagery can be used to track small scale solar density variations throughout the solar wind, serving as a proxy for in situ velocity detection, but with global and continuous coverage. Title: Non Linear Force Free Field modeling of an erupting pseudostreamer Authors: Karna, Nishu; Savcheva, Antonia Stefanova; Gibson, Sarah E.; Tassev, Svetlin Bibcode: 2018tess.conf10412K Altcode: Coronal mass ejections (CMEs) are the most violent eruptions in our Solar System. CMEs are responsible for large solar energetic particle events and severe geomagnetic storms. In this study, we present a magnetic configuration of an erupting pseudostreamer observed on April 19, 2015 on the Southern West limb embedding a prominence cavity. The eruption resulted in a relatively wide CME with a round front and prominence core. In SOHO/LASCO C2 partial halo was observed. The prominence eruption begins with a slow rise and then evolves to a fast rise phase. We first constructed a non-linear force free field (NLFFF) model of this erupting pseudostreamer using the flux rope insertion method. The NLFFF model produces the 3D coronal magnetic field constrained by observed coronal structures and photospheric magnetogram. SDO/HMI magnetogram was used as an input for the model. The field configurations representing the eruption are not in force-free equilibrium. We magnetofrictionally relax the model until the flux rope expands to three solar radii and compare CME propagation with the SOHO/LASCO C2 observations. From the simulation results, we determine the process for the eruption by identifying where reconnection takes place and how much flux is reconnected. We determine the pre-eruption twist and decay index and how the twist is transferred as the simulation progresses. In addition, we perform a topology analysis of the models in order to determine the location of quasi-separatrix layers (QSLs). QSLs are used as a proxy to determine where strong electric current sheets develop in the corona and also provide important information about the connectivity in this complicated magnetic field configuration. Title: Studies of Global Solar Magnetic Field Patterns Using a Newly Digitized Archive Authors: Gibson, Sarah E. Bibcode: 2018tess.conf10308G Altcode: The McIntosh Archive consists of a set of hand-drawn solar Carrington maps created by Patrick McIntosh from 1964 to 2009. McIntosh used mainly H-alpha, He 10830Å and photospheric magnetic measurements from both ground-based and NASA satellite observations. With these he traced polarity inversion lines (PILs), filaments, sunspots and plage and, later, coronal holes, yielding a unique 45-year record of features associated with the large-scale organization of the solar magnetic field. We discuss our efforts to preserve and digitize this archive. The original hand-drawn maps have been scanned, a method for processing these scans into digital, searchable format has been developed, and a website and an archival repository at NOAA's National Centers for Environmental Information (NCEI) has been created. Presently ~ 70% of the final processed archive is complete, from SC 20 through to the start of SC 24, but with long gaps in SCs 20, 21 and 22. Here we present preliminary results using the archived maps from SC 21-23. We show the global evolution of closed magnetic structures (e.g., sunspots, plage, and filaments) relative to open structures (e.g., coronal holes), and examine how both relate to the shifting patterns of large-scale positive and negative polarity regions. Title: Analyzing CME Substructure and Chirality from Synthetic Polarization Observations Authors: Gibson, Sarah E.; DeForest, Criag; de Koning, Curt A.; Fan, Yuhong Bibcode: 2018tess.conf30923G Altcode: Recent work (Deforest et al., 2017) has demonstrated the power of white-light polarization for pinpointing the 3D location of CME substructure and characterizing its chirality using coronagraph observations. In this paper, we further explore the capability of this technique by creating synthetic white-light observations from a simulation of an erupting CME containing realistic substructure. We extract information about the CME chirality from the synthetic polarization, and compare to the "ground truth" of the simulation. We analyze how CME orientation relative to the viewer affects our results, and consider the implications of this type of analysis for studying how CME substructure evolves in the young solar wind. Title: Studies of Global Solar Magnetic Field Patterns Using a Newly Digitized Archive Authors: Hewins, I.; Webb, D. F.; Gibson, S. E.; McFadden, R.; Emery, B. A.; Malanushenko, A. V. Bibcode: 2017AGUFMSH54A..01H Altcode: The McIntosh Archive consists of a set of hand-drawn solar Carrington maps created by Patrick McIntosh from 1964 to 2009. McIntosh used mainly Ha, He 10830Å and photospheric magnetic measurements from both ground-based and NASA satellite observations. With these he traced polarity inversion lines (PILs), filaments, sunspots and plage and, later, coronal holes, yielding a unique 45-year record of features associated with the large-scale organization of the solar magnetic field. We discuss our efforts to preserve and digitize this archive; the original hand-drawn maps have been scanned, a method for processing these scans into digital, searchable format has been developed, and a website and an archival repository at NOAA's National Centers for Environmental Information (NCEI) has been created. The archive is complete for SC 23 and partially complete for SCs 21 and 22. In this paper we show examples of how the data base can be utilized for scientific applications. We compare the evolution of the areas and boundaries of CHs with other recent results, and we use the maps to track the global, SC-evolution of filaments, large-scale positive and negative polarity regions, PILs and sunspots. Title: Numerical MHD Coronal Simulations: Energy Statistics and FORWARD Analysis. Authors: Nimmo, K.; Rempel, M.; Chen, F.; Gibson, S. E.; Fan, Y. Bibcode: 2017AGUFMSH43A2800N Altcode: We analyse a recent realistic radiative MHD simulation of the solar corona that was computed with the extended version of the MURaM code. The simulation covers the uppermost 8Mm of the solar convection zone and reaches 115Mm into the solar corona. The simulation covers 48 hours of solar time and simulates the evolution of a complex active region. The energy release in the corona is highly intermittent and we identify a total of 118 individual events including flares and a coronal mass ejection, which we analyse in further detail. From the simulation we compute an X-ray flux mimicking observations by the GOES (Geostationary Operational Environmental Satellite) satellite in the wavelength range 1-8 Å. The power law index for the GOES X-ray flux for flares of class C and above in this simulation is found to be 1.33452. We analyze the correlation between synthetic coronal emission during flares and the magnetic energy release in the corona. The latter is a quantity that cannot be directly determined in observations.The FORWARD code is a tool used for the purpose of coronal magnetometry. It can be used to compute synthetic observables from coronal models. We focus on the interpretation of the High Altitude Observatory's CoMP observations. The CoMP (COronal Multi-channel Polarimeter) instrument measures the intensity and the linear and circular polarisation of FeXIII at 1074.7nm.We discuss some important limitations of coronal emission line polarimetry when simulating an extremely active solar region, with emphasis on the influence of high velocities, temperatures and densities on the FORWARD output. Title: Type III Solar Radio Burst Source Region Splitting due to a Quasi-separatrix Layer Authors: McCauley, Patrick I.; Cairns, Iver H.; Morgan, John; Gibson, Sarah E.; Harding, James C.; Lonsdale, Colin; Oberoi, Divya Bibcode: 2017ApJ...851..151M Altcode: 2017arXiv171104930M We present low-frequency (80-240 MHz) radio imaging of type III solar radio bursts observed by the Murchison Widefield Array on 2015 September 21. The source region for each burst splits from one dominant component at higher frequencies into two increasingly separated components at lower frequencies. For channels below ∼132 MHz, the two components repetitively diverge at high speeds (0.1c-0.4c) along directions tangent to the limb, with each episode lasting just ∼2 s. We argue that both effects result from the strong magnetic field connectivity gradient that the burst-driving electron beams move into. Persistence mapping of extreme-ultraviolet jets observed by the Solar Dynamics Observatory reveals quasi-separatrix layers (QSLs) associated with coronal null points, including separatrix dome, spine, and curtain structures. Electrons are accelerated at the flare site toward an open QSL, where the beams follow diverging field lines to produce the source splitting, with larger separations at larger heights (lower frequencies). The splitting motion within individual frequency bands is interpreted as a projected time-of-flight effect, whereby electrons traveling along the outer field lines take slightly longer to excite emission at adjacent positions. Given this interpretation, we estimate an average beam speed of 0.2c. We also qualitatively describe the quiescent corona, noting in particular that a disk-center coronal hole transitions from being dark at higher frequencies to bright at lower frequencies, turning over around 120 MHz. These observations are compared to synthetic images based on the MHD algorithm outside a sphere (MAS) model, which we use to flux-calibrate the burst data. Title: Origins of the Ambient Solar Wind: Implications for Space Weather Authors: Cranmer, Steven R.; Gibson, Sarah E.; Riley, Pete Bibcode: 2017SSRv..212.1345C Altcode: 2017arXiv170807169C; 2017SSRv..tmp..167C The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress—in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory—that gives us hope that the above problems are indeed solvable. Title: Beyond sunspots: Studies using the McIntosh Archive of global solar magnetic field patterns Authors: Gibson, Sarah E.; Webb, David; Hewins, Ian M.; McFadden, Robert H.; Emery, Barbara A.; Denig, William; McIntosh, Patrick S. Bibcode: 2017IAUS..328...93G Altcode: 2018arXiv180808215G In 1964 (Solar Cycle 20; SC 20), Patrick McIntosh began creating hand-drawn synoptic maps of solar magnetic features, based on Hα images. These synoptic maps were unique in that they traced magnetic polarity inversion lines, and connected widely separated filaments, fibril patterns, and plage corridors to reveal the large-scale organization of the solar magnetic field. Coronal hole boundaries were later added to the maps, which were produced, more or less continuously, into 2009 (i.e., the start of SC 24). The result was a record of ~45 years (~570 Carrington rotations), or nearly four complete solar cycles of synoptic maps. We are currently scanning, digitizing and archiving these maps, with the final, searchable versions publicly available at NOAA's National Centers for Environmental Information. In this paper we present preliminary scientific studies using the archived maps from SC 23. We show the global evolution of closed magnetic structures (e.g., sunspots, plage, and filaments) in relation to open magnetic structures (e.g., coronal holes), and examine how both relate to the shifting patterns of large-scale positive and negative polarity regions. Title: Non Linear Force Free Field Modeling for a Pseudostreamer Authors: Karna, Nishu; Savcheva, Antonia; Gibson, Sarah; Tassev, Svetlin V. Bibcode: 2017SPD....48.0701K Altcode: In this study we present a magnetic configuration of a pseudostreamer observed on April 18, 2015 on southern west limb embedding a filament cavity. We constructed Non Linear Force Free Field (NLFFF) model using the flux rope insertion method. The NLFFF model produces the three-dimensional coronal magnetic field constrained by observed coronal structures and photospheric magnetogram. SDO/HMI magnetogram was used as an input for the model. The high spatial and temporal resolution of the SDO/AIA allows us to select best-fit models that match the observations. The MLSO/CoMP observations provide full-Sun observations of the magnetic field in the corona. The primary observables of CoMP are the four Stokes parameters (I, Q, U, V). In addition, we perform a topology analysis of the models in order to determine the location of quasi-separatrix layers (QSLs). QSLs are used as a proxy to determine where the strong electric current sheets can develop in the corona and also provide important information about the connectivity in complicated magnetic field configuration. We present the major properties of the 3D QSL and FLEDGE maps and the evolution of 3D coronal structures during the magnetofrictional process. We produce FORWARD-modeled observables from our NLFFF models and compare to a toy MHD FORWARD model and the observations. Title: Non Linear Force Free Field Modeling for a Pseudostreamer Authors: Karna, Nishu; Savcheva, Antonia; Gibson, Sarah Bibcode: 2017shin.confE..52K Altcode: In this study we present a magnetic configuration of a pseudostreamer observed on April 18, 2015 on southern west limb embedding a filament cavity. We constructed Non Linear Force Free Field (NLFFF) model using the flux rope insertion method. The NLFFF model produces the three-dimensional coronal magnetic field constrained by observed coronal structures and photospheric magnetogram. SDO/HMI magnetogram was used as an input for the model. The high spatial and temporal resolution of the SDO/AIA allows us to select best-fit models that match the observations. The MLSO/CoMP observations provide full-Sun observations of the magnetic field in the corona. The primary observables of CoMP are the four Stokes parameters (I, Q, U, V). In addition, we perform a topology analysis of the models in order to determine the location of quasi-separatrix layers (QSLs). QSLs are used as a proxy to determine where the strong electric current sheets can develop in the corona and also provide important information about the connectivity in complicated magnetic field configuration. We present the major properties of the 3D QSL and FLEDGE maps and the evolution of 3D coronal structures during the magnetofrictional process. Title: Editorial: Coronal Magnetometry Authors: Gibson, Sarah E.; Rachmeler, Laurel A.; White, Stephen M. Bibcode: 2017FrASS...4....3G Altcode: 2017FrASS...4E...3G No abstract at ADS Title: Magnetic Nulls and Super-radial Expansion in the Solar Corona Authors: Gibson, Sarah E.; Dalmasse, Kevin; Rachmeler, Laurel A.; De Rosa, Marc L.; Tomczyk, Steven; de Toma, Giuliana; Burkepile, Joan; Galloy, Michael Bibcode: 2017ApJ...840L..13G Altcode: 2017arXiv170407470G Magnetic fields in the Sun’s outer atmosphere—the corona—control both solar-wind acceleration and the dynamics of solar eruptions. We present the first clear observational evidence of coronal magnetic nulls in off-limb linearly polarized observations of pseudostreamers, taken by the Coronal Multichannel Polarimeter (CoMP) telescope. These nulls represent regions where magnetic reconnection is likely to act as a catalyst for solar activity. CoMP linear-polarization observations also provide an independent, coronal proxy for magnetic expansion into the solar wind, a quantity often used to parameterize and predict the solar wind speed at Earth. We introduce a new method for explicitly calculating expansion factors from CoMP coronal linear-polarization observations, which does not require photospheric extrapolations. We conclude that linearly polarized light is a powerful new diagnostic of critical coronal magnetic topologies and the expanding magnetic flux tubes that channel the solar wind. Title: Dynamics and diagnostics of the solar corona: unchained magnetism Authors: Gibson, Sarah Bibcode: 2017psio.confE..53G Altcode: No abstract at ADS Title: The McIntosh Archive: A solar feature database spanning four solar cycles Authors: Gibson, S. E.; Malanushenko, A. V.; Hewins, I.; McFadden, R.; Emery, B.; Webb, D. F.; Denig, W. F. Bibcode: 2016AGUFMSH11A2220G Altcode: The McIntosh Archive consists of a set of hand-drawn solar Carrington maps created by Patrick McIntosh from 1964 to 2009. McIntosh used mainly H-alpha, He-1 10830 and photospheric magnetic measurements from both ground-based and NASA satellite observations. With these he traced coronal holes, polarity inversion lines, filaments, sunspots and plage, yielding a unique 45-year record of the features associated with the large-scale solar magnetic field. We will present the results of recent efforts to preserve and digitize this archive. Most of the original hand-drawn maps have been scanned, a method for processing these scans into digital, searchable format has been developed and streamlined, and an archival repository at NOAA's National Centers for Environmental Information (NCEI) has been created. We will demonstrate how Solar Cycle 23 data may now be accessed and how it may be utilized for scientific applications. In addition, we will discuss how this database of human-recognized features, which overlaps with the onset of high-resolution, continuous modern solar data, may act as a training set for computer feature recognition algorithms. Title: Tapping the Core - a study of Alfvénic energy flow in an erupting flux-rope configuration Authors: Fletcher, L.; Dalmasse, K.; Gibson, S. E.; Fan, Y. Bibcode: 2016AGUFMSH31B2564F Altcode: We analyze the evolution of reconnecting magnetic field in a 3-D numerical simulation of a partially-ejected solar flux rope, with a focus on understanding how the flux rope dynamics is linked to the flow of energy through the field and the solar atmosphere as Alfvénic Poynting flux. The magnetic flux rope splits in two during its eruption, with reconnection taking place between the erupting rope and surrounding fields, and internally in the strong field of the rope. We track the Poynting flux entering and leaving the simulation current sheets, and by mapping this down to the solar surface we identify locations of weak and strong energy deposition in the lower atmosphere. Our tracking method enables us to link the lower atmosphere signatures to different stages of the coronal reconnection. We find a predominantly two-ribbon morphology in the locations of Poynting flux deposition in the lower atmosphere, in which the transition from reconnection involving weaker field external to the flux rope, to reconnection involving the flux rope core field, is accompanied by rapid ribbon spreading. In the core-field reconnection phase, ribbons move into strong field regions on the solar surface, and locations of highly concentrated downward-directed Poynting flux are found, which may be linked to the most energetic flare `footpoints' seen in optical and hard X-ray emission. Title: New Capabilities for Adaptive Mesh Simulation Use within FORWARD Authors: Mathews, N.; Flyer, N.; Gibson, S. E.; Kucera, T. A.; Manchester, W. Bibcode: 2016AGUFMSM32A..05M Altcode: The multiscale nature of the solar corona can pose challenges to numerical simulations. Adaptive meshes are often used to resolve fine-scale structures, such as the chromospheric-coronal interface found in prominences and the transition region as a whole. FORWARD is a SolarSoft IDL package designed as a community resource for creating a broad range of synthetic coronal observables from numerical models and comparing them to data. However, to date its interface with numerical simulations has been limited to regular grids. We will present a new adaptive-grid interface to FORWARD that will enable efficient synthesis of solar observations. This is accomplished through the use of hierarchical IDL structures designed to enable finding nearest-neighbor points quickly for non-uniform grids. This facilitates line-of-sight integrations that can adapt to the unequally spaced mesh. We will demonstrate this capability for the Alfven-Wave driven SOlar wind Model (AWSOM), part of the Space Weather Modeling Framework (SWMF). In addition, we will use it in the context of a prominence-cavity model, highlighting new capabilities in FORWARD that allow treatment of continuum absorbtion as well as EUV line emission via dual populations (chromosphere-corona). Title: Probing the Physical Connection between Solar Prominences and Coronal Rain Authors: Liu, W.; Antolin, P.; Sun, X.; Vial, J. C.; Guo, L.; Gibson, S. E.; Berger, T. E.; Okamoto, J.; De Pontieu, B. Bibcode: 2016AGUFMSH43C2587L Altcode: Solar prominences and coronal rain are intimately related phenomena, both involving cool material at chromospheric temperatures within the hot corona and both playing important roles as part of the return flow of the chromosphere-corona mass cycle. At the same time, they exhibit distinct morphologies and dynamics not yet well understood. Quiescent prominences consist of numerous long-lasting, filamentary downflow threads, while coronal rain is more transient and falls comparably faster along well-defined curved paths. We report here a novel, hybrid prominence-coronal rain complex in an arcade-fan geometry observed by SDO/AIA and IRIS, which provides new insights to the underlying physics of such contrasting behaviors. We found that the supra-arcade fan region hosts a prominence sheet consisting of meandering threads with broad line widths. As the prominence material descends to the arcade, it turns into coronal rain sliding down coronal loops with line widths 2-3 times narrower. This contrast suggests that distinct local plasma and magnetic conditions determine the fate of the cool material, a scenario supported by our magnetic field extrapolations from SDO/HMI. Specifically, the supra-arcade fan (similar to those in solar flares) is likely situated in a current sheet, where the magnetic field is weak and the plasma-beta could be close to unity, thus favoring turbulent flows like those prominence threads. In contrast, the underlying arcade has a stronger magnetic field and most likely a low-beta environment, such that the material is guided along magnetic field lines to appear as coronal rain. We will discuss the physical implications of these observations beyond the phenomena of prominences and coronal rain. Title: Joint SDO and IRIS Observations of a Novel, Hybrid Prominence-Coronal Rain Complex Authors: Liu, Wei; Antolin, Patrick; Sun, Xudong; Gao, Lijia; Vial, Jean-Claude; Gibson, Sarah; Okamoto, Takenori; Berger, Thomas; Uitenbroek, Han; De Pontieu, Bart Bibcode: 2016usc..confE..99L Altcode: Solar prominences and coronal rain are intimately related phenomena, both involving cool material at chromospheric temperatures within the hot corona and both playing important roles as part of the return flow of the chromosphere-corona mass cycle. At the same time, they exhibit distinct morphologies and dynamics not yet well understood. Quiescent prominences consist of numerous long-lasting, filamentary downflow threads, while coronal rain is more transient and falls comparably faster along well-defined curved paths. We report here a novel, hybrid prominence-coronal rain complex in an arcade-fan geometry observed by SDO/AIA and IRIS, which provides new insights to the underlying physics of such contrasting behaviors. We found that the supra-arcade fan region hosts a prominence sheet consisting of meandering threads with broad line widths. As the prominence material descends to the arcade, it turns into coronal rain sliding down coronal loops with line widths 2-3 times narrower. This contrast suggests that distinct local plasma and magnetic conditions determine the fate of the cool material, a scenario supported by our magnetic field extrapolations from SDO/HMI. Specifically, the supra-arcade fan (similar to those in solar flares; e.g., McKenzie 2013) is likely situated in a current sheet, where the magnetic field is weak and the plasma-beta could be close to unity, thus favoring turbulent flows like those prominence threads. In contrast, the underlying arcade has a stronger magnetic field and most likely a low-beta environment, such that the material is guided along magnetic field lines to appear as coronal rain. We will discuss the physical implications of these observations beyond prominence and coronal rain. Title: Studies Using a Newly Digitized Archive of Global Solar Magnetic Field Patterns Authors: Webb, David; Gibson, Sarah; Hewins, Ian; McFadden, Robert; Emery, Barbara; Denig, William Bibcode: 2016usc..confE..40W Altcode: In 1964 (Solar Cycle 20) Patrick McIntosh began creating hand-drawn synoptic maps of solar activity, based on Hα imaging measurements. These synoptic maps were unique in that they traced the polarity inversion lines (PILs), connecting widely separated filaments, fibril patterns and plage corridors to reveal the large-scale organization of the solar magnetic field. Coronal hole (CH) boundaries were later added to the maps which were produced, more or less continuously, into 2009 (start of SC 24), yielding more than 40 years ( 540 Carrington rotations) or nearly four complete solar cycles of synoptic maps. Under an NSF grant, these maps are being scanned, digitized and archived and the final, searchable versions are now publicly available at NOAA's National Centers for Environmental Information (NCEI) at: http://www.ngdc.noaa.gov/stp/space-weather/solar-data/solar-imagery/composites/synoptic-maps/mc-intosh/). We will outline the project and the current status of the archive, and present some preliminary results demonstrating scientific applications. For example, computer codes permit efficient searches of the map arrays. The maps for SC 23 have been completed and we will show examples of the global evolution of features including filaments, large-scale positive and negative polarity regions, CHs of each polarity, CH boundaries, PILs, major sunspots, and plage areas. Title: Scientific objectives and capabilities of the Coronal Solar Magnetism Observatory Authors: Tomczyk, S.; Landi, E.; Burkepile, J. T.; Casini, R.; DeLuca, E. E.; Fan, Y.; Gibson, S. E.; Lin, H.; McIntosh, S. W.; Solomon, S. C.; Toma, G.; Wijn, A. G.; Zhang, J. Bibcode: 2016JGRA..121.7470T Altcode: Magnetic influences increase in importance in the solar atmosphere from the photosphere out into the corona, yet our ability to routinely measure magnetic fields in the outer solar atmosphere is lacking. We describe the scientific objectives and capabilities of the COronal Solar Magnetism Observatory (COSMO), a proposed synoptic facility designed to measure magnetic fields and plasma properties in the large-scale solar atmosphere. COSMO comprises a suite of three instruments chosen to enable the study of the solar atmosphere as a coupled system: (1) a coronagraph with a 1.5 m aperture to measure the magnetic field, temperature, density, and dynamics of the corona; (2) an instrument for diagnostics of chromospheric and prominence magnetic fields and plasma properties; and (3) a white light K-coronagraph to measure the density structure and dynamics of the corona and coronal mass ejections. COSMO will provide a unique combination of magnetic field, density, temperature, and velocity observations in the corona and chromosphere that have the potential to transform our understanding of fundamental physical processes in the solar atmosphere and their role in the origins of solar variability and space weather. Title: Future space missions and ground observatory for measurements of coronal magnetic fields Authors: Fineschi, Silvano; Gibson, Sarah; Bemporad, Alessandro; Zhukov, Andrei; Damé, Luc; Susino, Roberto; Larruquert, Juan Bibcode: 2016cosp...41E.602F Altcode: This presentation gives an overview of the near-future perspectives for probing coronal magnetism from space missions (i.e., SCORE and ASPIICS) and ground-based observatory (ESCAPE). Spectro-polarimetric imaging of coronal emission-lines in the visible-light wavelength-band provides an important diagnostics tool of the coronal magnetism. The interpretation in terms of Hanle and Zeeman effect of the line-polarization in forbidden emission-lines yields information on the direction and strength of the coronal magnetic field. As study case, this presentation will describe the Torino Coronal Magnetograph (CorMag) for the spectro-polarimetric observation of the FeXIV, 530.3 nm, forbidden emission-line. CorMag - consisting of a Liquid Crystal (LC) Lyot filter and a LC linear polarimeter. The CorMag filter is part of the ESCAPE experiment to be based at the French-Italian Concordia base in Antarctica. The linear polarization by resonance scattering of coronal permitted line-emission in the ultraviolet (UV)can be modified by magnetic fields through the Hanle effect. Space-based UV spectro-polarimeters would provide an additional tool for the disgnostics of coronal magnetism. As a case study of space-borne UV spectro-polarimeters, this presentation will describe the future upgrade of the Sounding-rocket Coronagraphic Experiment (SCORE) to include new generation, high-efficiency UV polarizer with the capability of imaging polarimetry of the HI Lyman-α, 121.6 nm. SCORE is a multi-wavelength imager for the emission-lines, HeII 30.4 nm and HI 121.6 nm, and visible-light broad-band emission of the polarized K-corona. SCORE has flown successfully in 2009. The second lauch is scheduled in 2016. Proba-3 is the other future solar mission that would provide the opportunity of diagnosing the coronal magnetic field. Proba-3 is the first precision formation-flying mission to launched in 2019). A pair of satellites will fly together maintaining a fixed configuration as a 'large rigid structure' in space. The paired satellites will together form a 150-m long solar coronagraph (ASPIICS) to study the Sun's faint corona closer to the solar limb than has ever before been achieved. High-resolution imaging in polarized visible-light of shock waves generated by Coronal Mass Ejections would provide a diagnostics of the magnetic field in the pre-shock ambient corona. Title: Constraining coronal magnetic field models using coronal polarimetry Authors: Dalmasse, Kévin; Nychka, D. W.; Gibson, S. E.; Flyer, N.; Fan, Y. Bibcode: 2016shin.confE..42D Altcode: Knowing the 3D coronal magnetic field prior to the trigger of a coronal mass ejection (CME) is one of the key features for predicting their geomagnetic effect. Since the magnetic field is essentially measured at the photosphere, one must rely on models to obtain the 3D magnetic field in the corona. Various coronal observables can then be used to constrain the parameters, and hence the magnetic field, of these models. One type of observable that is receiving an increasing attention is coronal polarization of infrared lines such as the Fe XIII 10747 A and 10798 A lines observed by the Coronal Multichannel Polarimeter (CoMP), which are sensitive to the coronal magnetic field. By combining forward modeling with a novel optimization method applied to a synthetic test bed of a coronal magnetic flux rope, we show that the polarimetric signal of coronal infrared lines contains enough information to constrain the parameters, and hence the magnetic structure, of coronal magnetic field models. We discuss future plans for application of our method to solar observations. Title: ROAM: a Radial-basis-function Optimization Approximation Method for diagnosing the three-dimensional coronal magnetic field Authors: Dalmasse, Kevin; Nychka, Douglas; Gibson, Sarah; Fan, Yuhong; Flyer, Natasha Bibcode: 2016FrASS...3...24D Altcode: 2016arXiv160703460D The Coronal Multichannel Polarimeter (CoMP) routinely performs coronal polarimetric measurements using the Fe XIII 10747 Å and 10798 Å lines, which are sensitive to the coronal magnetic field. However, inverting such polarimetric measurements into magnetic field data is a difficult task because the corona is optically thin at these wavelengths and the observed signal is therefore the integrated emission of all the plasma along the line of sight. To overcome this difficulty, we take on a new approach that combines a parameterized 3D magnetic field model with forward modeling of the polarization signal. For that purpose, we develop a new, fast and efficient, optimization method for model-data fitting: the Radial-basis-functions Optimization Approximation Method (ROAM). Model-data fitting is achieved by optimizing a user-specified log-likelihood function that quantifies the differences between the observed polarization signal and its synthetic/predicted analogue. Speed and efficiency are obtained by combining sparse evaluation of the magnetic model with radial-basis-function (RBF) decomposition of the log-likelihood function. The RBF decomposition provides an analytical expression for the log-likelihood function that is used to inexpensively estimate the set of parameter values optimizing it. We test and validate ROAM on a synthetic test bed of a coronal magnetic flux rope and show that it performs well with a significantly sparse sample of the parameter space. We conclude that our optimization method is well-suited for fast and efficient model-data fitting and can be exploited for converting coronal polarimetric measurements, such as the ones provided by CoMP, into coronal magnetic field data. Title: Diagnostics of Coronal Magnetic Fields Through the Hanle Effect in UV and IR Lines Authors: Raouafi, Nour E.; Riley, Pete; Gibson, Sarah; Fineschi, Silvano; Solanki, Sami K. Bibcode: 2016FrASS...3...20R Altcode: 2016arXiv160608493R The plasma thermodynamics in the solar upper atmosphere, particularly in the corona, are dominated by the magnetic field, which controls the flow and dissipation of energy. The relative lack of knowledge of the coronal vector magnetic field is a major handicap for progress in coronal physics. This makes the development of measurement methods of coronal magnetic fields a high priority in solar physics. The Hanle effect in the UV and IR spectral lines is a largely unexplored diagnostic. We use magnetohydrodynamic (MHD) simulations to study the magnitude of the signal to be expected for typical coronal magnetic fields for selected spectral lines in the UV and IR wavelength ranges, namely the HI Ly-α and the He I 10830 Å lines. We show that the selected lines are useful for reliable diagnosis of coronal magnetic fields. The results show that the combination of polarization measurements of spectral lines with different sensitivities to the Hanle effect may be most appropriate for deducing coronal magnetic properties from future observations. Title: VizieR Online Data Catalog: JCMT Plane Survey: l=30° field (Moore+, 2015) Authors: Moore, T. J. T.; Plume, R.; Thompson, M. A.; Parsons, H.; Urquhart, J. S.; Eden, D. J.; Dempsey, J. T.; Morgan, L. K.; Thomas, H. S.; Buckle, J.; Brunt, C. M.; Butner, H.; Carretero, D.; Chrysostomou, A.; Devilliers, H. M.; Fich, M.; Hoare, M. G.; Manser, G.; Mottram, J. C.; Natario, C.; Olguin, F.; Peretto, N.; Polychroni, D.; Redman, R. O.; Rigby, A. J.; Salji, C.; Summers, L. J.; Berry, D.; Currie, M. J.; Jenness, T.; Pestalozzi, M.; Traficante, A.; Bastien, P.; Difrancesco, J.; Davis, C. J.; Evans, A.; Friberg, P.; Fuller, G. A.; Gibb, A. G.; Gibson, S.; Hill, T.; Johnstone, D.; Joncas, G.; Longmore, S. N.; Lumsden, S. L.; Martin, P. G.; Nguyen Luong, Q.; Pineda, J. E.; Purcell, C.; Richer, J. S.; Schieven, G. H.; Shipman, R.; Spaans, M.; Taylor, A. R.; Viti, S.; Weferling, B.; White, G. J.; Zhu, M. Bibcode: 2016yCat..74534264M Altcode: JPS uses the wide-field submm-band bolometer camera SCUBA-2 (the Submm Common-User Bolometer Array 2) in the 850um band at a spatial resolution of 14.5-arcsec.

The 850um survey data presented in this paper cover the l=30° field of the JPS and were observed between 2012 June and 2013 October. The 11 tiles making up the field were observed on average three times each. A strategy of minimum elevation limits for given atmospheric opacity bands within the allocated range was adopted, in order to minimize variations in the resulting noise in each repeated tile.

(1 data file). Title: Tracking a large pseudostreamer to pinpoint the southern polar magnetic field reversal Authors: Rachmeler, Laurel; Guennou, Chloé; Seaton, Daniel B.; Gibson, Sarah; Auchère, Frédéric Bibcode: 2016SPD....4740104R Altcode: The reversal of the solar polar magnetic field is notoriously hard to pin down due to the extreme viewing angle of the pole. In Cycle 24, the southern polar field reversal can be pinpointed with high accuracy due to a large-scale pseudostreamer that formed over the pole and persisted for approximately a year. We tracked the size and shape of this structure with multiple observations and analysis techniques including PROBA2/SWAP EUV images, AIA EUV images, CoMP data, and 3D tomographic reconstructions. We find that the heliospheric field reversed polarity in February 2014, whereas in the photosphere the last vestiges of the previous polar field polarity remained until March 2015. Title: CoMP linear polarization as a probe of coronal magnetic topology Authors: Gibson, Sarah; Bak-Steslicka, Urszula; de Toma, Giuliana; Rachmeler, Laurel A.; Zhang, Mei Bibcode: 2016SPD....4740103G Altcode: New data from HAO’s Coronal Multichannel Polarimeter (CoMP) have allowed us for the first time to obtain daily polarimetric observations of the solar atmosphere, providing unique constraints on coronal magnetic models. However, due to the relatively-small size of the telescope, polarization observations are currently limited to linear polarization measurements, which depend upon the plane-of-sky magnetic field direction but not its magnitude. Despite this limitation, and despite the fact that the linearly polarized light measured is optically thin and so integrated over the line of sight, CoMP linear polarization has proved useful as a probe of a range of magnetic topologies. In particular, we will use forward modeling in comparison to CoMP data to show how linear polarization diagnoses magnetic flux ropes, null points, pseudostreamers, non-radial expansion factor, and solar cycle evolution. Title: Towards a Data-Optimized Coronal Magnetic Field Model (DOC-FM): statistical method for diagnosing the coronal magnetic field Authors: Dalmasse, Kevin; Nychka, Doug; Gibson, Sarah; Fan, Yuhong; Flyer, Natasha Bibcode: 2016SPD....47.1004D Altcode: Knowing the 3D coronal magnetic field prior to the trigger of a CME is one of the key features for predicting their geomagnetic effect. Since the magnetic field is essentially measured at the photosphere, one must rely on reconstruction models to obtain the 3D magnetic field in the corona. Hence, obtaining an accurate model of the real 3D coronal magnetic field is one of the cornerstones for precise Space Weather Forecasting. In this work, we propose a new method for data-constrained reconstruction of the 3D coronal magnetic field. Model-data fitting is achieved by optimizing a user-specified log-likelihood, quantifying the difference between a dataset (including e.g. polarization, extreme-ultraviolet emission, X-ray emission) and its synthetic analogue. The synthetic data is produced by forward calculations applied to a 3D magnetic model that depends upon a finite set of parameters. After introducing the method, we present its validation on a synthetic test bed consisting of a coronal magnetic flux rope assumed to depend on three parameters, i.e. latitude, longitude, and tilt angle. A specific value of each parameter is used to generate a ground truth and the corresponding synthetic data. We show that our method performs well and the best-fit parameters provide a good approximation of the ground-truth parameters. We discuss future plans for validation and application of our method to solar observations. Title: Simulating Idealized Flux Ropes with the Flux Rope Insertion Method: A Parameter Space Exploration of Currents and Topology Authors: Savcheva, Antonia; Tassev, Svetlin; DeLuca, Edward E.; Gibson, Sarah; Fan, Yuhong Bibcode: 2016SPD....47.0330S Altcode: Knowledge of the 3D magnetic filed structure at the time of major solar eruptions is vital to the understanding of the space weather effects of these eruptions. Multiple data-constrained techniques that reconstruct the 3D coronal field based on photospheric magnetograms have been used to achieve this goal. In particular, we have used the flux rope insertion method to obtain the coronal magnetic field of multiple regions containing flux ropes or sheared arcades based on line-of-sight magnetograms and X-ray and EUV observations of coronal loops. For the purpose of developing statistical measures of the goodness of fit of these models to the observations, here we present our modeling of flux ropes based on synthetic magnetograms obtained from aFan & Gibson emerging flux rope simulation. The goal is to study the effect of of different input flux rope parameters on the geometry of currents, field line connectivity, and topology, in a controled setting. For this purpose we create a large grid of models with the flux rope insertion method with different combinations of axial and poloidal flux, which give us different morphology of the flux rope. We create synthetic images of these flux ropes in AIA passbands with the FORWARD forward-fitting code. The present parametric study will later be used to get a better handle on the initial condition for magnetofrictional and MHD simulations of observed regions containing flux ropes, such as sigmoids and polar-crown filaments. Title: Preserving a Unique Archive for Long-Term Solar Variability Studies Authors: Webb, David F.; Hewins, Ian; McFadden, Robert; Emery, Barbara; Gibson, Sarah; Denig, William Bibcode: 2016SPD....47.0206W Altcode: In 1964 (solar cycle 20) Patrick McIntosh began creating hand-drawn synoptic maps of solar activity, based on Hydrogen alpha (Hα) imaging measurements. These synoptic maps were unique because they traced the polarity inversion lines (PILs), connecting widely separated filaments, fibril patterns and plage corridors to reveal the large-scale organization of the solar magnetic field. He and his assistants later included coronal hole (CH) boundaries to the maps, usually from ground-based He-I 10830 images. They continued making these maps until 2010 (the start of solar cycle 24), yielding more than 40 years (~ 540 Carrington rotations) or nearly four complete solar cycles (SCs) of synoptic maps. The McIntosh collection of maps forms a unique and consistent set of global solar magnetic field data, and are unique tools for studying the structure and evolution of the large-scale solar fields and polarity boundaries, because: 1) they have excellent spatial resolution for defining polarity boundaries, 2) the organization of the fields into long-lived, coherent features is clear, and 3) the data are relatively homogeneous over four solar cycles. After digitization and archiving, these maps -- along with computer codes permitting efficient searches of the map arrays -- will be made publicly available at NOAA’s National Centers for Environmental Information (NCEI) in their final, searchable form. This poster is a progress report of the project so far and some suggested scientific applications. Title: Stability Study of Coronal Cavities and Prominences Authors: de Toma, Giuliana; Gibson, Sarah Bibcode: 2016SPD....47.0339D Altcode: Cavity/prominence systems are large-scale coronal structures that can live for many weeks and even months and often end their life in the form of large coronal eruptions. To determine the role of the surrounding ambient coronal field in stabilizing thesesystems against eruption, we examined the extent to which the decline with height of the external coronal magnetic field influences their evolution and likelihood to erupt. We selected coronal cavities observed with SDO/AIA during the rising phase of cycle 24 and divided them in two groups, eruptive and non-eruptive. The height of the cavity, both at the cavity center and top, was directly measured from the SDO/AIA images. The ambient coronal field was derived from a PFSS extrapolation of SDO/HMI magnetograms. We find that the decay index of the potential field above the coronal cavity varies significantly in value for both eruptive and non-eruptive cases but stable cavity systems have, on average, a lower decay index and less complex topology than the eruptive ones. Title: Division E Commission 49: Interplanetary Plasma and Heliosphere Authors: Mann, Ingrid; Manoharan, P. K.; Gopalswamy, Natchimuthuk; Briand, Carine; Chashei, Igor V.; Gibson, Sarah E.; Lario, David; Hanaoka, Yoichiro; Malandraki, Olga; Kontar, Eduard; Richardson, John D. Bibcode: 2016IAUTA..29..300M Altcode: After a little more than forty years of work related to the interplanetary plasma and the heliosphere the IAU's Commission 49 was formally discontinued in 2015. The commission started its work when the first spacecraft were launched to measure the solar wind in-situ away from Earth orbit, both inward and outward from 1 AU. It now hands over its activities to a new commission during an era of space research when Voyager 1 measures in-situ the parameters of the local interstellar medium at the edge of the heliosphere. The commission will be succeeded by C.E3 with a similar area of responsibility but with more focused specific tasks that the community intends to address during the coming several years. This report includes a short description of the motivation for this commission and of the historical context. It then describes work from 2012 to 2015 during the present solar cycle 24 that has been the weakest in the space era so far. It gave rise to a large number of studies on solar energetic particles and cosmic rays. Other studies addressed e.g. the variation of the solar wind structure and energetic particle fluxes on long time scales, the detection of dust in the solar wind and the Voyager measurements at the edge of the heliosphere. The research is based on measurements from spacecraft that are at present operational and motivated by the upcoming Solar Probe + and Solar Orbiter missions to explore the vicinity of the Sun. We also report here the progress on new and planned radio instruments and their importance for heliospheric studies. Contributors to this report are Carine Briand, Yoichiro Hanaoka, Eduard Kontar, David Lario, Ingrid Mann, John D. Richardson. Title: Division E Commission 10: Solar Activity Authors: Schrijver, Carolus J.; Fletcher, Lyndsay; van Driel-Gesztelyi, Lidia; Asai, Ayumi; Cally, Paul S.; Charbonneau, Paul; Gibson, Sarah E.; Gomez, Daniel; Hasan, Siraj S.; Veronig, Astrid M.; Yan, Yihua Bibcode: 2016IAUTA..29..245S Altcode: 2015arXiv151003348S After more than half a century of community support related to the science of ``solar activity'', IAU's Commission 10 was formally discontinued in 2015, to be succeeded by C.E2 with the same area of responsibility. On this occasion, we look back at the growth of the scientific disciplines involved around the world over almost a full century. Solar activity and fields of research looking into the related physics of the heliosphere continue to be vibrant and growing, with currently over 2,000 refereed publications appearing per year from over 4,000 unique authors, publishing in dozens of distinct journals and meeting in dozens of workshops and conferences each year. The size of the rapidly growing community and of the observational and computational data volumes, along with the multitude of connections into other branches of astrophysics, pose significant challenges; aspects of these challenges are beginning to be addressed through, among others, the development of new systems of literature reviews, machine-searchable archives for data and publications, and virtual observatories. As customary in these reports, we highlight some of the research topics that have seen particular interest over the most recent triennium, specifically active-region magnetic fields, coronal thermal structure, coronal seismology, flares and eruptions, and the variability of solar activity on long time scales. We close with a collection of developments, discoveries, and surprises that illustrate the range and dynamics of the discipline. Title: Line-of-sight velocity as a tracer of coronal cavity magnetic structure Authors: Bak-Steslicka, Urszula; Gibson, Sarah; Chmielewska, Ewa Bibcode: 2016FrASS...3....7B Altcode: We present a statistical analysis of 66 days of observations of quiescent (non-erupting) coronal cavities and associated velocity and thermal structures. We find that nested rings of LOS-oriented velocity are common in occurrence and spatially well correlated with cavities observed in emission. We find that the majority of cavities possess multiple rings, and a range in velocity on the order of several km/sec. We find that the tops of prominences lie systematically below the cavity center and location of largest Doppler velocity. Finally, we use DEM analysis to consider the temperature structure of two cavities in relation to cavity, prominence, and flows. These observations yield new constraints on the magnetic structure of cavities, and on the conditions leading up to solar eruptions. Title: FORWARD: A toolset for multiwavelength coronal magnetometry Authors: Gibson, Sarah; Kucera, Therese; White, Stephen; Dove, James; Fan, Yuhong; Forland, Blake; Rachmeler, Laurel; Downs, Cooper; Reeves, Katharine Bibcode: 2016FrASS...3....8G Altcode: Determining the 3D coronal magnetic field is a critical, but extremely difficult problem to solve. Since different types of multiwavelength coronal data probe different aspects of the coronal magnetic field, ideally these data should be used together to validate and constrain specifications of that field. Such a task requires the ability to create observable quantities at a range of wavelengths from a distribution of magnetic field and associated plasma -- i.e., to perform forward calculations. In this paper we describe the capabilities of the FORWARD SolarSoft IDL package, a uniquely comprehensive toolset for coronal magnetometry. FORWARD is a community resource that may be used both to synthesize a broad range of coronal observables, and to access and compare synthetic observables to existing data. It enables forward fitting of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties. FORWARD can also be used to generate synthetic test beds from MHD simulations in order to facilitate the development of coronal magnetometric inversion methods, and to prepare for the analysis of future large solar telescope data. Title: Waves and Magnetism in the Solar Atmosphere (WAMIS) Authors: Ko, Yuan-Kuen; Moses, John; Laming, John; Strachan, Leonard; Tun Beltran, Samuel; Tomczyk, Steven; Gibson, Sarah; Auchere, Frederic; Casini, Roberto; Fineschi, Silvano; Knoelker, Michael; Korendyke, Clarence; McIntosh, Scott; Romoli, Marco; Rybak, Jan; Socker, Dennis; Vourlidas, Angelos; Wu, Qian Bibcode: 2016FrASS...3....1K Altcode: Comprehensive measurements of magnetic fields in the solar corona have a long history as an important scientific goal. Besides being crucial to understanding coronal structures and the Sun’s generation of space weather, direct measurements of their strength and direction are also crucial steps in understanding observed wave motions. In this regard, the remote sensing instrumentation used to make coronal magnetic field measurements is well suited to measuring the Doppler signature of waves in the solar structures. In this paper, we describe the design and scientific values of the Waves and Magnetism in the Solar Atmosphere (WAMIS) investigation. WAMIS, taking advantage of greatly improved infrared filters and detectors, forward models, advanced diagnostic tools and inversion codes, is a long-duration high-altitude balloon payload designed to obtain a breakthrough in the measurement of coronal magnetic fields and in advancing the understanding of the interaction of these fields with space plasmas. It consists of a 20 cm aperture coronagraph with a visible-IR spectro-polarimeter focal plane assembly. The balloon altitude would provide minimum sky background and atmospheric scattering at the wavelengths in which these observations are made. It would also enable continuous measurements of the strength and direction of coronal magnetic fields without interruptions from the day-night cycle and weather. These measurements will be made over a large field-of-view allowing one to distinguish the magnetic signatures of different coronal structures, and at the spatial and temporal resolutions required to address outstanding problems in coronal physics. Additionally, WAMIS could obtain near simultaneous observations of the electron scattered K-corona for context and to obtain the electron density. These comprehensive observations are not provided by any current single ground-based or space observatory. The fundamental advancements achieved by the near-space observations of WAMIS on coronal field would point the way for future ground based and orbital instrumentation. Title: Probing Solar Eruption by Tracking Magnetic Cavities and Filaments Authors: Sterling, A. C.; Johnson, J. R.; Moore, R. L.; Gibson, S. E. Bibcode: 2015AGUFMSH53B2489S Altcode: A solar eruption is a tremendous explosion on the Sun that happens when energy stored in twisted (or distorted) magnetic fields is suddenly released. When this field is viewed along the axis of the twist in projection at the limb, e.g. in EUV or white-light coronal images, the outer portions of the pre-eruption magnetic structure sometimes appears as a region of weaker emission, called a "coronal cavity," surrounded by a brighter envelope. Often a chromospheric filament resides near the base of the cavity and parallel to the cavity's central axis. Typically, both the cavity and filament move outward from the Sun at the start of an eruption of the magnetic field in which the cavity and filament reside. Studying properties the cavities and filaments just prior to and during eruption can help constrain models that attempt to explain why and how the eruptions occur. In this study, we examined six different at-limb solar eruptions using images from the Extreme Ultraviolet Imaging Telescope (EIT) aboard the Solar and Heliospheric Observatory (SOHO). For four of these eruptions we observed both cavities and filaments, while for the remaining two eruptions, one had only a cavity and the other only a filament visible in EIT images. All six eruptions were in comparatively-quiet solar regions, with one in the neighborhood of the polar crown. We measured the height and velocities of the cavities and filaments just prior to and during the start of their fast-eruption onsets. Our results support that the filament and cavity are integral parts of a single large-scale erupting magnetic-field system. We examined whether the eruption-onset heights were correlated with the expected magnetic field strengths of the eruption-source regions, but no clear correlation was found. We discuss possible reasons for this lack of correlation, and we also discuss future research directions. The research performed was supported by the National Science Foundation under Grant No. AGS-1460767; J.J. participated in the Research Experience for Undergraduates (REU) program, at NASA/MSFC. Additional support was from a grant from the NASA LWS program. Title: Three-Dimensional Reconstruction of the Electron Density in the Solar Corona Authors: Burnett, L. W.; Nychka, D. W.; Gibson, S. E.; Dalmasse, K. Bibcode: 2015AGUFMSH53B2495B Altcode: The need to understand the Sun's magnetic field motivates much of present-day solar physics research. Our ultimate goal is to quantitatively validate models of the global coronal magnetic field by comparing forward models of synthetic data to real observations. As a necessary first step, we seek to build a three-dimensional (3D) model of the electron density in the solar corona, based on white-light coronagraph data. Given that these observations are two-dimensional snapshots, we employ a new application of statistical tomography to piece together the full 3D picture. In an initial step, we demonstrate that our method is capable of reconstructing geometrically-simple density formations. We next turn to more realistic coronal density structures as represented by the global magnetohydrodynamic models made available by Predictive Science Inc., and integrated to create synthetic data using the FORWARD SolarSoft codes. Finally, we consider the application of our method to Mauna Loa Solar Observatory K-Coronagraph observations, and discuss the strengths and limitations of our method. Title: Towards a Data-Optimized Coronal Magnetic Field Model (DOC-FM): Synthetic Test Beds and Multiwavelength Forward Modeling Authors: Gibson, S. E.; Dalmasse, K.; Fan, Y.; Fineschi, S.; MacKay, D.; Rempel, M.; White, S. M. Bibcode: 2015AGUFMSH54B..04G Altcode: Understanding the physical state of the solar corona is key to deciphering the origins of space weather as well as to realistically representing the environment to be navigated by missions such as Solar Orbiter and Solar Probe Plus. However, inverting solar coronal observations to reconstruct this physical state -- and in particular the three-dimensional coronal magnetic field - is complicated by limited lines of sight and by projection effects. On the other hand, the sensitivity of multiwavelength observations to different physical mechanisms implies a potential for simultaneous probing of different parts of the coronal plasma. In order to study this complementarity, and to ultimately establish an optimal set of observations for constraining the three-dimensional coronal magnetic field, we are developing a suite of representative simulations to act as diagnostic test beds. We will present three such test beds: a coronal active region, a quiescent prominence, and a global corona. Each fully define the physical state of density, temperature, and vector magnetic field in three dimensions throughout the simulation domain. From these test beds, and using the FORWARD SolarSoft IDL codes, we will create a broad range of synthetic data. Radio observables will include intensity and circular polarization (including gyroresonance effects) and Faraday rotation for a range of frequencies. Infrared and visible forbidden line diagnostics of Zeeman and saturated Hanle effects will yield full Stokes vector (I, Q, U, V) synthetic data, and UV permitted line Hanle diagnostics will yield intensity and linear polarization. In addition, we will synthesize UV and SXR imager data, UV/EUV spectrometric data, and white light brightness and polarized brightness. All of these synthetic data, along with the "ground truth" physical state of the simulations from which they are derived, will be made available to the community for the purpose of testing coronal inversion techniques. Title: Towards a Data-Optimized Coronal Magnetic Field Model (DOC-FM): Simulating Flux Ropes with the Flux Rope Insertion Method Authors: Dalmasse, K.; DeLuca, E. E.; Savcheva, A. S.; Gibson, S. E.; Fan, Y. Bibcode: 2015AGUFMSH51B2444D Altcode: Knowledge of the 3D magnetic filed structure at the time of major solar eruptions is vital or understanding of the space weather effects of these eruptions. Multiple data-constrained techniques that reconstruct the 3D coronal field based on photospheric magnetograms have been used to achieve this goal. In particular, we have used the flux rope insertion method to obtain the coronal magnetic field of multiple regions containing flux ropes or sheared arcades based on line-of-sight magnetograms and X-ray and EUV observations of coronal loops. For the purpose of developing statistical measures of the goodness of fit of these models to the observations, here we present our modeling of flux ropes based on synthetic magnetograms obtained from Fan & Gibson emerging flux rope simulation. The goal is to reproduce the flux rope structure from a given time step of the MHD simulations based only on the photospheric magnetogram and synthetic forward modeled coronal emission obtained from the same step of the MHD simulation. For this purpose we create a large grid of models with the flux rope insertion method with different combinations of axial and poloidal flux, which give us different morphology of the flux rope. Then we compare the synthetic coronal emission with the shape of the current distribution and field lines from the models to come up with a best fit. This fit is then tested using the statistical methods developed by our team. Title: a Roadmap to Advance Understanding of the Science of Space Weather Authors: Schrijver, K.; Kauristie, K.; Aylward, A.; De Nardin, C. M.; Gibson, S. E.; Glover, A.; Gopalswamy, N.; Grande, M.; Hapgood, M. A.; Heynderickx, D.; Jakowski, N.; Kalegaev, V. V.; Lapenta, G.; Linker, J.; Liu, S.; Mandrini, C. H.; Mann, I. R.; Nagatsuma, T.; Nandy, D.; Obara, T.; O'Brien, T. P., III; Onsager, T. G.; Opgenoorth, H. J.; Terkildsen, M. B.; Valladares, C. E.; Vilmer, N. Bibcode: 2015AGUFMSH12A..01S Altcode: There is a growing appreciation that the environmental conditions that we call space weather impact the technological infrastructure that powers the coupled economies around the world. With that comes the need to better shield society against space weather by improving forecasts, environmental specifications, and infrastructure design. A COSPAR/ILWS team recently completed a roadmap that identifies the scientific focus areas and research infrastructure that are needed to significantly advance our understanding of space weather of all intensities and of its implications and costs for society. This presentation provides a summary of the highest-priority recommendations from that roadmap. Title: Towards a Data-Optimized Coronal Magnetic Field Model (DOC-FM): Statistical Method for Diagnosing the Coronal Magnetic Field Authors: Dalmasse, K.; Nychka, D. W.; Gibson, S. E.; Fan, Y. Bibcode: 2015AGUFMSH21B2395D Altcode: Solar coronal mass ejections (CMEs) and solar flares are the main drivers of space weather. Their potential impact on Earth is determined by the morphology and orientation of the magnetic structure associated with these events and its evolution as it propagates into the interplanetary magnetic field. Knowing the 3D coronal magnetic field prior to the trigger of a CME is therefore one of the key features for predicting their geomagnetic effect. Since the magnetic field is essentially measured at the photosphere, one must rely on reconstruction models to obtain the 3D magnetic field in the corona. Hence, obtaining an accurate model of the real 3D coronal magnetic field is one of the cornerstones for precise Space Weather Forecasting. In this work, we propose a new method for data-constrained reconstruction of the 3D coronal magnetic field. Model-data fitting is achieved by optimizing a user-specified metric, M, quantifying the difference between a dataset (including e.g. polarization, extreme-ultraviolet emission, X-ray emission) and its synthetic analogue. The synthetic data is produced by forward calculations applied to a 3D magnetic model that depends upon a finite set of parameters. After introducing the method, we present its validation on a synthetic test bed consisting of a coronal magnetic flux rope assumed to depend on four parameters, i.e. height in the corona, latitude, longitude, and tilt angle. A specific value of each parameter is used to generate a ground truth and the corresponding synthetic data. We show that, when M does not possess any degenerate minimum, our method performs well and the best-fit parameters provide a good approximation of the ground-truth parameters. We then show how using additional observations can help in removing any existing degeneracy. Finally, we discuss future plans for validation and application of our method to solar observations. Title: The JCMT Plane Survey: early results from the ℓ = 30° field Authors: Moore, T. J. T.; Plume, R.; Thompson, M. A.; Parsons, H.; Urquhart, J. S.; Eden, D. J.; Dempsey, J. T.; Morgan, L. K.; Thomas, H. S.; Buckle, J.; Brunt, C. M.; Butner, H.; Carretero, D.; Chrysostomou, A.; deVilliers, H. M.; Fich, M.; Hoare, M. G.; Manser, G.; Mottram, J. C.; Natario, C.; Olguin, F.; Peretto, N.; Polychroni, D.; Redman, R. O.; Rigby, A. J.; Salji, C.; Summers, L. J.; Berry, D.; Currie, M. J.; Jenness, T.; Pestalozzi, M.; Traficante, A.; Bastien, P.; diFrancesco, J.; Davis, C. J.; Evans, A.; Friberg, P.; Fuller, G. A.; Gibb, A. G.; Gibson, S.; Hill, T.; Johnstone, D.; Joncas, G.; Longmore, S. N.; Lumsden, S. L.; Martin, P. G.; Nguyen Lu'o'ng, Q.; Pineda, J. E.; Purcell, C.; Richer, J. S.; Schieven, G. H.; Shipman, R.; Spaans, M.; Taylor, A. R.; Viti, S.; Weferling, B.; White, G. J.; Zhu, M. Bibcode: 2015MNRAS.453.4264M Altcode: 2015arXiv150900318M We present early results from the JCMT (James Clerk Maxwell Telescope) Plane Survey (JPS), which has surveyed the northern inner Galactic plane between longitudes ℓ = 7° and ℓ = 63° in the 850-μm continuum with SCUBA-2 (Submm Common-User Bolometer Array 2), as part of the JCMT Legacy Survey programme. Data from the ℓ = 30° survey region, which contains the massive-star-forming regions W43 and G29.96, are analysed after approximately 40 per cent of the observations had been completed. The pixel-to-pixel noise is found to be 19 mJy beam-1 after a smooth over the beam area, and the projected equivalent noise levels in the final survey are expected to be around 10 mJy beam-1. An initial extraction of compact sources was performed using the FELLWALKER method, resulting in the detection of 1029 sources above a 5σ surface-brightness threshold. The completeness limits in these data are estimated to be around 0.2 Jy beam-1 (peak flux density) and 0.8 Jy (integrated flux density) and are therefore probably already dominated by source confusion in this relatively crowded section of the survey. The flux densities of extracted compact sources are consistent with those of matching detections in the shallower APEX (Atacama Pathfinder Experiment) Telescope Large Area Survey of the Galaxy (ATLASGAL) survey. We analyse the virial and evolutionary state of the detected clumps in the W43 star-forming complex and find that they appear younger than the Galactic-plane average. Title: Waves and Magnetism in the Solar Atmosphere (WAMIS) Authors: Strachan, L.; Ko, Y. -K.; Moses, J. D.; Laming, J. M.; Auchere, F.; Casini, R.; Fineschi, S.; Gibson, S.; Knoelker, M.; Korendyke, C.; Mcintosh, S.; Romoli, M.; Rybak, J.; Socker, D.; Tomczyk, S.; Vourlidas, A.; Wu, Q. Bibcode: 2015IAUS..305..121S Altcode: Magnetic fields in the solar atmosphere provide the energy for most varieties of solar activity, including high-energy electromagnetic radiation, solar energetic particles, flares, and coronal mass ejections, as well as powering the solar wind. Despite the fundamental role of magnetic fields in solar and heliospheric physics, there exist only very limited measurements of the field above the base of the corona. What is needed are direct measurements of not only the strength and orientation of the magnetic field but also the signatures of wave motions in order to better understand coronal structure, solar activity, and the role of MHD waves in heating and accelerating the solar wind. Fortunately, the remote sensing instrumentation used to make magnetic field measurements is also well suited to measure the Doppler signature of waves in the solar structures. We present here a mission concept for the Waves And Magnetism In the Solar Atmosphere (WAMIS) experiment which is proposed for a NASA long-duration balloon flight. Title: Data-model comparison using FORWARD and CoMP Authors: Gibson, Sarah Bibcode: 2015IAUS..305..245G Altcode: 2015arXiv151104416G The FORWARD SolarSoft IDL package is a community resource for model-data comparison, with a particular emphasis on analyzing coronal magnetic fields. FORWARD allows the synthesis of coronal polarimetric signals at visible, infrared, and radio frequencies, and will soon be augmented for ultraviolet polarimetry. In this paper we focus on observations of the infrared (IR) forbidden lines of Fe XIII, and describe how FORWARD may be used to directly access these data from the Mauna Loa Solar Observatory Coronal Multi-channel Polarimeter (MLSO/CoMP), to put them in the context of other space- and ground-based observations, and to compare them to synthetic observables generated from magnetohydrodynamic (MHD) models. Title: Magnetism Matters: Coronal Magnetometry Using Multi-Wavelength Polarimetry Authors: Gibson, Sarah E. Bibcode: 2015IAUGA..2230393G Altcode: The solar coronal magnetic field is key both to solving fundamental problems in solar physics such as coronal heating and solar wind acceleration, and to predicting the internal magnetic structure and thus space-weather impact of coronal mass ejections. I will describe the current state of the art in coronal magnetometry, and present results from the Coronal Multichannel Polarimeter (CoMP) at Mauna Loa Solar Observatory (MLSO), which since 2011 has taken polarimetric observations of the solar corona in the near-infrared on a near-daily basis. I will discuss work in progress that utilizes forward modeling to synthesize polarimetric data at multiple heights and vantage points, and at wavelengths from radio to infrared to visible to ultraviolet. The goal is to use such synthetic testbeds to determine the ideal set of observations for constraining the coronal magnetic field, and to establish a Data-Optimized Coronal Field Model (DOC-FM) that efficiently incorporates these data into global magnetic models. This work will provide essential tools and motivation for the planning and implementation of future coronal polarimetric projects and missions spanning a broad range of wavelengths. Title: Understanding space weather to shield society: A global road map for 2015-2025 commissioned by COSPAR and ILWS Authors: Schrijver, Carolus J.; Kauristie, Kirsti; Aylward, Alan D.; Denardini, Clezio M.; Gibson, Sarah E.; Glover, Alexi; Gopalswamy, Nat; Grande, Manuel; Hapgood, Mike; Heynderickx, Daniel; Jakowski, Norbert; Kalegaev, Vladimir V.; Lapenta, Giovanni; Linker, Jon A.; Liu, Siqing; Mandrini, Cristina H.; Mann, Ian R.; Nagatsuma, Tsutomu; Nandy, Dibyendu; Obara, Takahiro; Paul O'Brien, T.; Onsager, Terrance; Opgenoorth, Hermann J.; Terkildsen, Michael; Valladares, Cesar E.; Vilmer, Nicole Bibcode: 2015AdSpR..55.2745S Altcode: 2015arXiv150306135S There is a growing appreciation that the environmental conditions that we call space weather impact the technological infrastructure that powers the coupled economies around the world. With that comes the need to better shield society against space weather by improving forecasts, environmental specifications, and infrastructure design. We recognize that much progress has been made and continues to be made with a powerful suite of research observatories on the ground and in space, forming the basis of a Sun-Earth system observatory. But the domain of space weather is vast - extending from deep within the Sun to far outside the planetary orbits - and the physics complex - including couplings between various types of physical processes that link scales and domains from the microscopic to large parts of the solar system. Consequently, advanced understanding of space weather requires a coordinated international approach to effectively provide awareness of the processes within the Sun-Earth system through observation-driven models. This roadmap prioritizes the scientific focus areas and research infrastructure that are needed to significantly advance our understanding of space weather of all intensities and of its implications for society. Advancement of the existing system observatory through the addition of small to moderate state-of-the-art capabilities designed to fill observational gaps will enable significant advances. Such a strategy requires urgent action: key instrumentation needs to be sustained, and action needs to be taken before core capabilities are lost in the aging ensemble. We recommend advances through priority focus (1) on observation-based modeling throughout the Sun-Earth system, (2) on forecasts more than 12 h ahead of the magnetic structure of incoming coronal mass ejections, (3) on understanding the geospace response to variable solar-wind stresses that lead to intense geomagnetically-induced currents and ionospheric and radiation storms, and (4) on developing a comprehensive specification of space climate, including the characterization of extreme space storms to guide resilient and robust engineering of technological infrastructures. The roadmap clusters its implementation recommendations by formulating three action pathways, and outlines needed instrumentation and research programs and infrastructure for each of these. An executive summary provides an overview of all recommendations. Title: Coronal Cavities: Observations and Implications for the Magnetic Environment of Prominences Authors: Gibson, Sarah Bibcode: 2015ASSL..415..323G Altcode: 2017arXiv170202214G Dark and elliptical, coronal cavities yield important clues to the magnetic structures that cradle prominences, and to the forces that ultimately lead to their eruption. We review observational analyses of cavity morphology, thermal properties (density and temperature), line-of-sight and plane-of-sky flows, substructure including hot cores and central voids, linear polarization signatures, and observational precursors and predictors of eruption. We discuss a magnetohydrodynamic interpretation of these observations which argues that the cavity is a magnetic flux rope, and pose a set of open questions for further study. Title: Coronal Magnetism and Forward Solarsoft Idl Package Authors: Gibson, S. E. Bibcode: 2014AGUFMSH13A4065G Altcode: The FORWARD suite of Solar Soft IDL codes is a community resource for model-data comparison, with a particular emphasis on analyzing coronal magnetic fields. FORWARD may be used both to synthesize a broad range of coronal observables, and to access and compare to existing data. FORWARD works with numerical model datacubes, interfaces with the web-served Predictive Science Inc MAS simulation datacubes and the Solar Soft IDL Potential Field Source Surface (PFSS) package, and also includes several analytic models (more can be added). It connects to the Virtual Solar Observatory and other web-served observations to download data in a format directly comparable to model predictions. It utilizes the CHIANTI database in modeling UV/EUV lines, and links to the CLE polarimetry synthesis code for forbidden coronal lines. FORWARD enables "forward-fitting" of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties. Title: 3D Location of Small Solar Wind Tracers Authors: Lopez-Portela, C.; Blanco-Cano, X.; Panasenco, O.; Gibson, S. E. Bibcode: 2014AGUFMSH21B4126L Altcode: The so-called "blobs" as defined in Sheeley et al., 1997, are small-scale structures embedded in the continuously expanding white-light solar corona and are considered to be tracers of the slow solar wind. As blobs are very faint structures, we considered long periods (around 2 to 5 days) where there were no coronal mass ejections (CME). The scarce presence of CMEs during the extended past solar minimum has permitted the identification of continuous blobs detachments, allowing us to estimate their un-projected trajectories between 2 and 15 solar radii (Mierla et al., 2008). In agreement with the idea that blobs are liberated from the cusps of helmet steamers (Wang et al., 1998), we constrained the observing region of interest in the coronagraphs field of view to ±30° from the Sun's equator. We studied cases where blobs were detected by the coronagraphs C2/LASCO and COR2/SECCHI, and inferred their source locations using two packages that implement the 3D potential field source surface (PFSS) model: (1) PFSS developed by De Rosa (2010) and (2) PFSS (De Rosa) in FORWARD (people.hao.ucar.edu/sgibson/FORWARD/). The locations of the origin of blobs that we find, support previous results that track down the origin of the slow solar wind to regions near the helmet streamers and pseudostreamers (Wang et al., 2012, Riley&Luhmann, 2012). Additionally, we found that in some cases blobs are coming from the boundaries of growing or decaying equatorial coronal holes, where the interchange reconnection issupposed to be faster. Title: Waves and Magnetism in the Solar Atmosphere (WAMIS) Authors: Ko, Y. K.; Auchere, F.; Casini, R.; Fineschi, S.; Gibson, S. E.; Knoelker, M.; Korendyke, C.; Laming, J. M.; Mcintosh, S. W.; Moses, J. D.; Romoli, M.; Rybak, J.; Socker, D. G.; Strachan, L.; Tomczyk, S.; Vourlidas, A.; Wu, Q. Bibcode: 2014AGUFMSH53B4221K Altcode: Magnetic fields in the solar atmosphere provide the energy for most varieties of solar activity, including high-energy electromagnetic radiation, solar energetic particles, flares, and coronal mass ejections, as well as powering the solar wind. Despite the fundamental role of magnetic fields in solar and heliospheric physics, there exists only very limited measurements of the field above the base of the corona. What is needed are direct measurements of not only the strength and orientation of the magnetic field but also the signatures of wave motions in order to better understand coronal structure, solar activity and the role of MHD waves in heating and accelerating the solar wind. Fortunately, the remote sensing instrumentation used to make magnetic field measurements is also well suited for measuring the Doppler signature of waves in the solar structures. With this in mind, we are proposing the WAMIS (Waves and Magnetism in the Solar Atmosphere) investigation. WAMIS will take advantage of greatly improved infrared (IR) detectors, forward models, advanced diagnostic tools and inversion codes to obtain a breakthrough in the measurement of coronal magnetic fields and in the understanding of the interaction of these fields with space plasmas. This will be achieved with a high altitude balloon borne payload consisting of a coronagraph with an IR spectro-polarimeter focal plane assembly. The balloon platform provides minimum atmospheric absorption and scattering at the IR wavelengths in which these observations are made. Additionally, a NASA long duration balloon flight mission from the Antarctic can achieve continuous observations over most of a solar rotation, covering all of the key time scales for the evolution of coronal magnetic fields. With these improvements in key technologies along with experience gained from current ground-based instrumentation, WAMIS will provide a low-cost mission with a high technology readiness leve. Title: Statistical study of the origin and 3D acceleration profile of small solar wind tracers (blobs) Authors: Lopez-Portela, Cynthia; Blanco-Cano, Xóchtil; Gibson, Sarah; Panansenco, Olga Bibcode: 2014shin.confE..44L Altcode: Blobs are small density enhancements observed in the solar corona (Sheeley et al. 1997). The study of blob propagation is important because they are considered to be tracers of the slow component of the solar wind. To explore the physical mechanisms behind the propagation of the slow solar wind, we have studied the kinematics of blobs embedded in the continuously expanding solar corona along the years 2007 to 2008, i.e., during the extended past solar minimum. The scarce presence of CMEs events during the selected periods of observation, has permitted the identification of around 100 blob-like structures on the LASCO and SECCHI coronagraphs on board SOHO and STEREO missions, respectively. This allowed us to estimate their un-projected trajectories between 2 and 15 solar radii, using the Height-Time technique (Mierla et al., 2008). In agreement with the idea that blobs are liberated from the cusps of helmet steamers (Wang et al., 1998) and considering their latitudinal distribution during the selected periods of observation, we constrained the observing region of interest in the coronagraphs field of view to ≤30° from the Sun's equator. We inferred their location in the close solar corona by the tridimensional Potential Field Source Surface (PFSS) developed by De Rosa (2003) and implemented in the FORWARD package (people.hao.ucar.edu/sgibson/FORWARD/). Our results support previous findings that track down the origin of the slow solar wind to neighboring regions of helmet streamers and pseudostreamers (Wiegelmann et al., 1998, Wang et al., 2012). Title: FORWARD: Forward modeling of coronal observables Authors: Gibson, Sarah E.; Kucera, Therese A.; Casini, Roberto; Dove, James; Forland, Blake; Judge, Philip; Rachmeler, Laurel Bibcode: 2014ascl.soft05007G Altcode: 2014ascl.soft05007F FORWARD forward models various coronal observables and can access and compare existing data. Given a coronal model, it can produce many different synthetic observables (including Stokes polarimetry), as well as plots of model plasma properties (density, magnetic field, etc.). It uses the CHIANTI database (ascl:9911.004) and CLE polarimetry synthesis code, works with numerical model datacubes, interfaces with the PFSS module of SolarSoft (ascl:1208.013), includes several analytic models, and connects to the Virtual Solar Observatory for downloading data in a format directly comparable to model predictions. Title: LOS velocity as a tracer of coronal cavity magnetic structure Authors: Bak-Steslicka, Urszula; Gibson, Sarah; Fan, Yuhong Bibcode: 2014cosp...40E.184B Altcode: The Coronal Multi-Channel Polarimeter (CoMP) makes daily observations of the lower corona in linear polarization, but also measures Doppler shifts, which allows us to obtain the line-of-sight velocity of coronal plasma. CoMP observations of polarization of coronal emission allows, for the first time, an analysis of the coronal magnetic field direction in quiescent prominence cavities. We present an analysis of Doppler velocity measurements of the numerous quiescent prominence cavities. Such observations are common in cavities and characteristic concentric circles of different values of flow may appear. CoMP data analysis of quiescent cavities is important for understanding pre-CME configuration. Title: The Formation of a Cavity in a 3D Flux Rope Authors: Schmit, Donald; Gibson, Sarah Bibcode: 2014IAUS..300..147S Altcode: 2013arXiv1311.2384S There are currently no three dimensional numerical models which describe the magnetic and energetic formation of prominences self-consistently. Consequently, there has not been significant progress made in understanding the connection between the dense prominence plasma and the coronal cavity. We have taken an ad-hoc approach to understanding the energetic implications of the magnetic models of prominence structure. We extract one dimensional magnetic field lines from a 3D MHD model of a flux rope and solve for hydrostatic balance along these field lines incorporating field-aligned thermal conduction, uniform heating, and radiative losses. The 1D hydrostatic solutions for density and temperature are then mapped back into three dimensional space, which allows us to consider the projection of multiple structures. We find that the 3D flux rope is composed of several distinct field line types. A majority of the flux rope interior field lines are twisted but not dipped. These field lines are density-reduced relative to unsheared arcade field lines. We suggest the cavity may form along these short interior field lines which are surrounded by a sheath of dipped field lines. This geometric arrangement would create a cavity on top of a prominence, but the two structures would not share field lines or plasma. Title: FORWARD: A toolset for analyzing coronal magnetic fields Authors: Gibson, Sarah Bibcode: 2014cosp...40E.986G Altcode: The FORWARD suite of Solar Soft IDL codes is a community resource for model-data comparison, with a particular emphasis on analyzing coronal magnetic fields. FORWARD may be used both to synthesize a broad range of coronal observables, and to access and compare to existing data. FORWARD works with numerical model datacubes, interfaces with the Solar Soft IDL Potential Field Source Surface (PFSS) package, and also includes several analytic models (more can be added). It utilizes the Chianti database, and connects to the Virtual Solar Observatory to download data in a format directly comparable to model predictions. FORWARD enables "forward-fitting" of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties. Title: The solar physics FORWARD codes: Now with widgets! Authors: Forland, Blake; Gibson, Sarah; Dove, James; Kucera, Therese Bibcode: 2014IAUS..300..414F Altcode: We have developed a suite of forward-modeling IDL codes (FORWARD) to convert analytic models or simulation data cubes into coronal observables, allowing a direct comparison with observations. Observables such as extreme ultraviolet, soft X-ray, white light, and polarization images from the Coronal Multichannel Polarimeter (CoMP) can be reproduced. The observer's viewpoint is also incorporated in the FORWARD analysis and the codes can output the results in a variety of forms in order to easily create movies, Carrington maps, or simply observable information at a particular point in the plane of the sky. We present a newly developed front end to the FORWARD codes which utilizes IDL widgets to facilitate ease of use by the solar physics community. Our ultimate goal is to provide as useful a tool as possible for a broad range of scientific applications. Title: The spatial relation between EUV cavities and linear polarization signatures Authors: Bak-Stȩślicka, Urszula; Gibson, Sarah E.; Fan, Yuhong; Bethge, Christian; Forland, Blake; Rachmeler, Laurel A. Bibcode: 2014IAUS..300..395B Altcode: Solar coronal cavities are regions of rarefied density and elliptical cross-section. The Coronal Multi-channel Polarimeter (CoMP) obtains daily full-Sun coronal observations in linear polarization, allowing a systematic analysis of the coronal magnetic field in polar-crown prominence cavities. These cavities commonly possess a characteristic ``lagomorphic'' signature in linear polarization that may be explained by a magnetic flux-rope model. We analyze the spatial relation between the EUV cavity and the CoMP linear polarization signature. Title: Magnetism and the Invisible Man: The mysteries of coronal cavities Authors: Gibson, Sarah Bibcode: 2014IAUS..300..139G Altcode: 2017arXiv171109254G Magnetism defines the complex and dynamic solar corona. Twists and tangles in coronal magnetic fields build up energy and ultimately erupt, hurling plasma into interplanetary space. These coronal mass ejections (CMEs) are transient riders on the ever-outflowing solar wind, which itself possesses a three-dimensional morphology shaped by the global coronal magnetic field. Coronal magnetism is thus at the heart of any understanding of the origins of space weather at the Earth. However, we have historically been limited by the difficulty of directly measuring the magnetic fields of the corona, and have turned to observations of coronal plasma to trace out magnetic structure. This approach is complicated by the fact that plasma temperatures and densities vary among coronal magnetic structures, so that looking at any one wavelength of light only shows part of the picture. In fact, in some regimes it is the lack of plasma that is a significant indicator of the magnetic field. Such a case is the coronal cavity: a dark, elliptical region in which strong and twisted magnetism dwells. I will elucidate these enigmatic features by presenting observations of coronal cavities in multiple wavelengths and from a variety of observing vantages, including unprecedented coronal magnetic field measurements now being obtained by the Coronal Multichannel Polarimeter (CoMP). These observations demonstrate the presence of twisted magnetic fields within cavities, and also provide clues to how and why cavities ultimately erupt as CMEs. Title: Prominence Mass Supply and the Cavity Authors: Schmit, Donald J.; Gibson, S.; Luna, M.; Karpen, J.; Innes, D. Bibcode: 2013ApJ...779..156S Altcode: 2013arXiv1311.2382S A prevalent but untested paradigm is often used to describe the prominence-cavity system: the cavity is under-dense because it is evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolution of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model with diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prominence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 Å bandpass near the prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of our one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure. Title: Coronal Cavity Survey: Morphological Clues to Eruptive Magnetic Topologies Authors: Forland, B. C.; Gibson, S. E.; Dove, J. B.; Rachmeler, L. A.; Fan, Y. Bibcode: 2013SoPh..288..603F Altcode: We present a survey on coronal prominence cavities conducted using 19 months of data from the Atmospheric Imaging Assembly (AIA) instrument aboard the Solar Dynamics Observatory (SDO) satellite. Coronal cavities are elliptical regions of rarefied density lying above and around prominences. They can be long-lived (weeks to months) but are often observed to eventually erupt as part of a coronal mass ejection (CME). We determine morphological properties of the cavities both by qualitatively assessing their shape, and quantitatively fitting them with ellipses. We demonstrate consistency between these two approaches, and find that fitted ellipses are taller than they are wide for almost all cavities studied, in agreement with an earlier analysis of white-light cavities. We examine correlations between cavity shape, aspect ratio, and propensity for eruption. We find that cavities with a teardrop-shaped morphology are more likely to erupt, and we discuss the implications of this morphology for magnetic topologies associated with CME models. We provide the full details of the survey for broad scientific use as supplemental material. Title: SDO/AIA Observations of a Partially Erupting Prominence Authors: Tripathi, Durgesh; Reeves, Katharine K.; Gibson, Sarah E.; Srivastava, Abhishek; Joshi, Navin C. Bibcode: 2013ApJ...778..142T Altcode: 2013arXiv1310.0162T We report an observation of a partially erupting prominence and its associated dynamical plasma processes based on observations recorded by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. The prominence first went through a slow rise (SR) phase followed by a fast rise (FR) phase. The SR phase began after a couple of small brightenings were seen toward the footpoints. When the prominence had transitioned from SR to FR, it had already become kinked. The prominence shows strong brightening at the central kink location during the start of FR. We interpret this as an internal magnetic reconnection occurring at a vertical current sheet forming between the two legs of the erupting prominence (flux rope). The brightening at the central kink location is seen in all EUV channels of AIA. The contributions of differential emission at higher temperatures are larger compared to that for typical coronal temperatures supporting a reconnection scenario at the central kink location. The plasma above the brightening location is ejected as a hot plasmoid-like structure embedded in a coronal mass ejection, and those below the brightening move down in the form of blobs moving toward the Sun's surface. The unique time resolution of the AIA has allowed these eruptive aspects, including SR-to-FR, kinking, central current sheet formation, plasmoid-like eruption, and filament "splitting," to be observed in a single event, providing strong and comprehensive evidence in favor of the model of partially erupting flux ropes. Title: Polarimetric Properties of Flux Ropes and Sheared Arcades in Coronal Prominence Cavities Authors: Rachmeler, L. A.; Gibson, S. E.; Dove, J. B.; DeVore, C. R.; Fan, Y. Bibcode: 2013SoPh..288..617R Altcode: 2013arXiv1304.7594R The coronal magnetic field is the primary driver of solar dynamic events. Linear and circular polarization signals of certain infrared coronal emission lines contain information about the magnetic field, and to access this information either a forward or an inversion method must be used. We study three coronal magnetic configurations that are applicable to polar-crown filament cavities by doing forward calculations to produce synthetic polarization data. We analyze these forward data to determine the distinguishing characteristics of each model. We conclude that it is possible to distinguish between cylindrical flux ropes, spheromak flux ropes, and sheared arcades using coronal polarization measurements. If one of these models is found to be consistent with observational measurements, it will mean positive identification of the magnetic morphology that surrounds certain quiescent filaments, which will lead to a better understanding of how they form and why they erupt. Title: Observations of Coronal Mass Ejections with the Coronal Multichannel Polarimeter Authors: Tian, H.; Tomczyk, S.; McIntosh, S. W.; Bethge, C.; de Toma, G.; Gibson, S. Bibcode: 2013SoPh..288..637T Altcode: 2013arXiv1303.4647T The Coronal Multichannel Polarimeter (CoMP) measures not only the polarization of coronal emission, but also the full radiance profiles of coronal emission lines. For the first time, CoMP observations provide high-cadence image sequences of the coronal line intensity, Doppler shift, and line width simultaneously over a large field of view. By studying the Doppler shift and line width we may explore more of the physical processes of the initiation and propagation of coronal mass ejections (CMEs). Here we identify a list of CMEs observed by CoMP and present the first results of these observations. Our preliminary analysis shows that CMEs are usually associated with greatly increased Doppler shift and enhanced line width. These new observations provide not only valuable information to constrain CME models and probe various processes during the initial propagation of CMEs in the low corona, but also offer a possible cost-effective and low-risk means of space-weather monitoring. Title: Two Novel Parameters to Evaluate the Global Complexity of the Sun's Magnetic Field and Track the Solar Cycle Authors: Zhao, L.; Landi, E.; Gibson, S. E. Bibcode: 2013ApJ...773..157Z Altcode: Since the unusually prolonged and weak solar minimum between solar cycles 23 and 24 (2008-2010), the sunspot number is smaller and the overall morphology of the Sun's magnetic field is more complicated (i.e., less of a dipole component and more of a tilted current sheet) compared with the same minimum and ascending phases of the previous cycle. Nearly 13 yr after the last solar maximum (~2000), the monthly sunspot number is currently only at half the highest value of the past cycle's maximum, whereas the polar magnetic field of the Sun is reversing (north pole first). These circumstances make it timely to consider alternatives to the sunspot number for tracking the Sun's magnetic cycle and measuring its complexity. In this study, we introduce two novel parameters, the standard deviation (SD) of the latitude of the heliospheric current sheet (HCS) and the integrated slope (SL) of the HCS, to evaluate the complexity of the Sun's magnetic field and track the solar cycle. SD and SL are obtained from the magnetic synoptic maps calculated by a potential field source surface model. We find that SD and SL are sensitive to the complexity of the HCS: (1) they have low values when the HCS is flat at solar minimum, and high values when the HCS is highly tilted at solar maximum; (2) they respond to the topology of the HCS differently, as a higher SD value indicates that a larger part of the HCS extends to higher latitude, while a higher SL value implies that the HCS is wavier; (3) they are good indicators of magnetically anomalous cycles. Based on the comparison between SD and SL with the normalized sunspot number in the most recent four solar cycles, we find that in 2011 the solar magnetic field had attained a similar complexity as compared to the previous maxima. In addition, in the ascending phase of cycle 24, SD and SL in the northern hemisphere were on the average much greater than in the southern hemisphere, indicating a more tilted and wavier HCS in the north than the south, associated with the early reversal of the polar magnetic field in the north relative to the south. Title: Morphology and Temperature of a Hot Prominence Cavity Observed with SDO Authors: Weber, Mark A.; Reeves, K.; Gibson, S.; Kucera, T. A. Bibcode: 2013SPD....44...39W Altcode: Prominence cavities appear as circularly shaped voids in coronal emission over polarity inversion lines where a prominence channel is straddling the solar limb. The presence of chromospheric material suspended at coronal altitudes is a common but not necessary feature within these cavities. These voids are observed to change shape as a prominence feature rotates around the limb. We apply temperature diagnostics to SDO data to investigate the thermal structure. We find significant evidence that the prominence cavity is hotter than the corona immediately outside the cavity boundary. This investigation follows upon ``Thermal Properties of A Solar Coronal Cavity Observed with the X-ray Telescope on Hinode'' by Reeves et al., 2012, ApJ, in press. M. Weber and K.K. Reeves are supported under contract NNM07AB07C from NASA to SAO. T. Kucera is supported by an award from the NASA SHP Program. Title: FORWARD Codes: Now with Widget! Authors: Gibson, Sarah; Forland, B.; Kucera, T. A. Bibcode: 2013SPD....44...49G Altcode: The FORWARD suite of SolarSoft IDL codes converts an analytic or simulation data cube into a form directly comparable to observations. Observables such as extreme ultraviolet, soft X-ray, white light, and polarization images from the Coronal Multichannel Polarimeter (CoMP) can be reproduced. The observer's viewpoint is also incorperated in the forward analysis and the codes can output the results in a variety of forms in order to easily create movies, Carrington maps, or simply plasma properties at a particular point in the plane of the sky. We present a newly developed front end to the FORWARD codes which utilizes IDL widgets. Our ultimate goal is to provide as useful a tool as possible for a broad range of scientific applications.Abstract (2,250 Maximum Characters): The FORWARD suite of SolarSoft IDL codes converts an analytic or simulation data cube into a form directly comparable to observations. Observables such as extreme ultraviolet, soft X-ray, white light, and polarization images from the Coronal Multichannel Polarimeter (CoMP) can be reproduced. The observer's viewpoint is also incorperated in the forward analysis and the codes can output the results in a variety of forms in order to easily create movies, Carrington maps, or simply plasma properties at a particular point in the plane of the sky. We present a newly developed front end to the FORWARD codes which utilizes IDL widgets. Our ultimate goal is to provide as useful a tool as possible for a broad range of scientific applications. Title: Association of solar wind proton flux extremes with pseudostreamers Authors: Zhao, L.; Gibson, S. E.; Fisk, L. A. Bibcode: 2013JGRA..118.2834Z Altcode: We investigate the characteristics and solar origins of a subpopulation of the solar wind that possesses extreme values of proton flux. Ulysses observations including solar wind magnetic flux, proton flux, number density and velocity, and ionic composition are examined in this study. We find that the departures of solar wind proton flux from its constancy occur for time intervals leading up to and encompassing the past two solar minima, and the extreme-proton-flux wind possesses the following characteristics: (1) it generally originates from sources middle-distant from the Heliospheric Current Sheet (HCS); (2) it is associated with a broad range of velocities and electron temperatures but excludes very fast/cold wind; (3) it exhibits anticorrelation between electron temperature and proton velocity, as does the rest of the solar wind; (4) it has extreme proton density values relative to the rest of the solar wind; and (5) the extreme-high-proton-flux wind has radial component of open magnetic flux (Br) greater than the rest of the solar wind, and both extreme-high and extreme-low wind do not possess the lowest values of Br flux. Comparing with SOHO EIT 195 Å coronal images, we find the observed extreme-proton-flux wind has temporal and spatial coincidence with the appearance of low-latitude coronal holes present in the recent two solar minima; the magnetic field lines extrapolated by the Potential Field Source Surface model confirm there are coronal pseudostreamer structures involved. So we propose that these extreme-proton-flux winds can be associated with mid- to low-latitude coronal holes and "pseudostreamer" structures. Title: Diagnosing the Prominence-Cavity Connection Authors: Schmit, Donald J.; Gibson, Sarah Bibcode: 2013ApJ...770...35S Altcode: 2013arXiv1304.7595S Prominences and cavities are ubiquitously observed together, but the physical link between these disparate structures has not been established. We address this issue by using dynamic emission in the extreme ultraviolet to probe the connections of these structures. The SDO/AIA observations show that the cavity exhibits excessive emission variability compared to the surrounding quiet-Sun streamer, particularly in the 171 Å bandpass. We find that this dynamic emission takes the form of coherent loop-like brightening structures which emanate from the prominence into the central cavity. The geometry of these structures, dubbed prominence horns, generally mimics the curvature of the cavity boundary. We use a space-time statistical analysis of two cavities in multiple AIA bandpasses to constrain the energetic properties of 45 horns. In general, we find there is a positive correlation between the light curves of the horns in the 171 Å and 193 Å bandpasses; however, the 193 Å emission is a factor of five weaker. There is also a strong correlation between structural changes to the prominence as viewed in the He II 304 Å bandpass and the enhanced 171 Å emission. In that bandpass, the prominence appears to extend several megameters along the 171 Å horn where we observe co-spatial, co-temporal 304 Å and 171 Å emission dynamics. We present these observations as evidence of the magnetic and energetic connection between the prominence and the cavity. Further modeling work is necessary to explain the physical source and consequences of these events, particularly in the context of the traditional paradigm: the cavity is underdense because it supplies mass to the overdense prominence. Title: Association of Solar Wind Proton Flux Extremes with Pseudostreamers Authors: Zhao, Liang; Gibson, S. E.; Fisk, L. A. Bibcode: 2013shin.confE..58Z Altcode: We investigate the characteristics and solar origins of a sub-population of the solar wind that possesses extreme values of proton flux. Ulysses observations including solar wind magnetic flux, proton flux, number density and velocity, and ionic composition are examined in this study. We find the departures of solar wind proton flux from its constancy occur for time intervals leading up to and encompassing the past two solar minima, and the extreme proton-flux wind possesses the following characteristics: 1) it generally originates from sources middle-distant from the Heliospheric Current Sheet (HCS); 2) it is associated with a broad range of velocities and electron temperatures, but excludes very fast/cold wind; 3) it exhibits anticorrelation between electron temperature and proton velocity, as does the rest of the solar wind; 4) it has extreme proton density values relative to the rest of the solar wind; and 5) the extreme-high-proton-flux wind has radial component of open magnetic flux (Br) greater than the rest of the solar wind and both extreme-high and extreme-low wind do not possess the lowest values of Br flux. Comparing with SOHO EIT 195 Å coronal images, we find the observed extreme proton-flux wind has temporal and spatial coincidence with the appearance of low latitude coronal holes present in the recent two solar minima; and the magnetic field lines extrapolated by the Potential Field Source Surface (PFSS) model confirm there are coronal pseudostreamer structures involved. So we propose that these extreme-proton-flux wind can be associated with mid-to-low-latitude coronal holes and "pseudostreamer" structures. Title: The Magnetic Structure of Solar Prominence Cavities: New Observational Signature Revealed by Coronal Magnetometry Authors: Bąk-Stȩślicka, Urszula; Gibson, Sarah E.; Fan, Yuhong; Bethge, Christian; Forland, Blake; Rachmeler, Laurel A. Bibcode: 2013ApJ...770L..28B Altcode: 2013arXiv1304.7388B The Coronal Multi-Channel Polarimeter (CoMP) obtains daily full-Sun above-the-limb coronal observations in linear polarization, allowing, for the first time, a diagnostic of the coronal magnetic field direction in quiescent prominence cavities. We find that these cavities consistently possess a characteristic "lagomorphic" signature in linear polarization indicating twist or shear extending up into the cavity above the neutral line. We demonstrate that such a signature may be explained by a magnetic flux-rope model, a topology with implications for solar eruptions. We find corroborating evidence for a flux-rope structure in the pattern of concentric rings within cavities seen in CoMP line-of-sight velocity. Title: Solar wind proton flux extremes and their association with pseudostreamers Authors: Zhao, Liang; Gibson, Sarah E.; Fisk, Lennard A. Bibcode: 2013AIPC.1539...94Z Altcode: Proton flux, as defined by the product of proton number density and proton speed, while exhibiting remarkable constancy across heliographic latitudes from pole to equator as measured by the Ulysses spacecraft, nevertheless showed obvious departure from this constancy for some mid-latitude wind and extended to high heliomagnetic latitudes during the recent two solar minima. We examine the solar wind exclusive of ICMEs from Ulysses and ACE observations, to analyze the solar wind in-situ data exhibiting extremes in proton flux. We first find these extreme-proton-flux winds generally originate in latitudes middle-distant from the heliospheric current sheet (HCS), and they have relatively slower speed than the bulk of the solar wind. Then we map the in-situ ACE observations in Carrington rotation (CR) 1997 back to the solar surface by using the Potential-Field-Source-Surface (PFSS) model, in order to consider the coronal properties at the extreme-proton-flux wind sources. We find there is a clear association between these extreme-proton-flux solar wind and the mid-latitude coronal holes and "pseudostreamer" structures. Title: FORWARD Codes: Now with Widgets! Authors: Forland, B.; Gibson, S. E.; Kucera, T. A. Bibcode: 2013AGUSMSH51A..02F Altcode: The FORWARD suite of SolarSoft IDL codes converts an analytic model or simulation data cube into a form directly comparable to observations. Observables such as extreme ultra violet, soft X-ray, white light, and polarization images from the Coronal Multichannel Polarimeter (CoMP) can be reproduced. The observer's viewpoint is also incorporated in the forward analysis and the codes can output the results in a variety of forms in order to easily create movies, Carrington maps, or simply observable information at a particular point in the plane of the sky. We present a newly developed front end to the FORWARD codes which utilizes IDL widgets to facilitate ease of use by the solar physics community. Our ultimate goal is to provide as useful a tool as possible for a broad range of scientific applications. Title: Magnetic structure and flows in coronal prominence cavities Authors: Gibson, S. E.; Bak-Steslicka, U.; Forland, B.; Schmit, D. J. Bibcode: 2013AGUSMSH23B..04G Altcode: Prominence cavities provide deep insight into the storage and release of magnetic energy in the solar corona. Recent studies have yielded a variety of observations that provide new constraints on models of prominences, cavities, and coronal mass ejections. In particular, a survey of SDO/AIA extreme-ultraviolet cavities has demonstrated that a tear-shaped morphology is a predictor of impending eruption, indicating that a change in topology may play a role in their destabilization. Other studies utilizing extreme-ultraviolet and infrared observations have shown both circulating plane-of-sky flows and a "bulls-eye" pattern in line-of-sight flows within cavities, indicating a central magnetic axis. A comparison of coronal flows within the cavity and flows associated with the embedded prominence demonstrate both spatial and temporal correlations, indicating they are both magnetically and thermodynamically connected. Finally, coronal magnetometric observations show a characteristic "rabbit-head" signature in linear polarization within polar-crown-prominence cavities, indicating twisted or sheared magnetic field at the heart of the cavity. All of these observations lend credence to the model of the cavity as a magnetic flux rope: both as a long-lived MHD equilibrium state and as a key component in the ultimate destabilization and eruption of coronal mass ejections. Title: Association of Solar Wind Proton Flux Extremes with Pseudostreamers Authors: Zhao, L.; Gibson, S. E.; Fisk, L. A. Bibcode: 2013AGUSMSH23A..01Z Altcode: We investigate the characteristics and solar origins of a sub-population of the solar wind that possesses extreme values of proton flux. Ulysses observations including solar wind magnetic flux, proton flux, number density and velocity, and ionic composition are examined in this study. We find the departures of solar wind proton flux from its constancy occur for time intervals leading up to and encompassing the past two solar minima, and the extreme-proton-flux wind possesses the following characteristics: 1) it generally originates from sources middle-distant from the Heliospheric Current Sheet (HCS); 2) it is associated with a broad range of velocities and electron temperatures, but excludes very fast/cold wind; 3) it exhibits anticorrelation between electron temperature and proton velocity, as does the rest of the solar wind; 4) it has extreme proton density values relative to the rest of the solar wind; and 5) the extreme-high-proton-flux wind has radial component of open magnetic flux (Br) greater than the rest of the solar wind and both extreme-high and extreme-low wind do not possess the lowest values of Br flux. Comparing with SOHO EIT 195 A coronal images, we find the observed extreme-proton-flux wind has temporal and special coincidence with the appearance of low latitude coronal holes present in the recent two solar minima; and the magnetic field lines extrapolated by the Potential Field Source Surface (PFSS) model confirm there are coronal pseudostreamer structures involved. So we propose that these extreme-proton-flux wind can be associated with mid-to-low-latitude coronal holes and "pseudostreamer" structures. Title: Formation of a hot plasma blob: observations of AIA, CoMP and MK4 Authors: Tian, Hui; Gibson, Sarah Bibcode: 2013enss.confE.107T Altcode: Using AIA observations, we found that a hot blob of plasma formed as a trans-equatorial loop system rose and opened up. The hot blob was most clearly seen in the AIA 94 passband and not obvious in any other passbands. A cusp-like structure quickly developed below the hot blob when the blob left the FOV of AIA 1.5 hours after its formation. This event was also observed by the CoMP and MK4 instruments in Mauna Loa Solar Observatory. The CoMP observation reveals a clear "bunny ear" pattern suggestive of a magnetic flux rope around the AIA blob. The hot blob observed by AIA seems to coincide with the region of enhanced linear polarization between the two dark ears. A comparison between these observations with MHD simulations of flux rope eruption suggest that the hot blob might be the lower part of, or just below, the erupted flux rope. In the MK4 data we see a clear three-part CME propagating outward. Title: Interpreting Coronal Polarization Observations Authors: Rachmeler, L. A.; Casini, R.; Gibson, S. E. Bibcode: 2012ASPC..463..227R Altcode: Solar coronal polarization observations are an underused data product because of the difficulties in interpreting the data and in calculating an inversion.The physics of the polarization is well understood and documented in the literature. The purpose of this paper is to present a general overview on how to interpret polarization signals without calculating an inversion. This is intended to introduce the data to those who are unfamiliar to polarization, and in so doing, make the data more accessible. Title: Preliminary Result from an Observational and Modeling Study of Coronal Pseudostreamer Structure as a Solar Wind Origin Authors: Zhao, L.; Gibson, S. E.; Fisk, L. A. Bibcode: 2012AGUFMSH52A..02Z Altcode: Unlike the polar coronal holes, which are the source of fast, cold solar wind, or helmet streamers, associated with slow, hot wind, the so-called "pseudostreamers" are still not well-categorized as a solar wind source, and the source of the slow- and intermediate- speed solar wind is still under debate. The solar wind proton mass flux, while exhibiting remarkable constancy across heliographic latitudes from pole to equator as measured by the Ulysses spacecraft, nevertheless showed departure from this constancy for some mid-latitude wind in the recent two solar minima. Such departures were most obvious during the 23-24 solar minimum and extended to high heliomagnetic latitudes. We examine the non-transient solar wind from Ulysses and ACE observations in the recent two solar minima, including solar wind magnetic flux, proton mass flux and velocity, and ionic composition O7+/O6+ as an indicator of coronal electron temperature, in order to analyze the solar wind exhibiting extremes in proton mass flux. The average proton speed of the extreme-mass-flux wind is in the slow to intermediate range. By applying potential-field-source-surface (PFSS) model to track the observed solar wind to the solar surface and comparing with the solar coronal structures there, we found there is a highly association between the sources of those slow- to intermediate-speed extreme-mass-flux solar wind and the low-latitude coronal holes and pseudostreamers structures. We will also discuss the observational constraints this study has placed on models of solar wind acceleration. Title: Solar Cycles 23 and 24: Effects in the Heliosphere Authors: Webb, D. F.; Gibson, S. E. Bibcode: 2012AGUFMSH12A..06W Altcode: The recent extended minimum was the lowest and longest minimum in about a century, having weak polar magnetic fields, a complex corona and heliosphere, and recurrent high speed streams. During this recent minimum, the solar magnetic field achieved a solar maximum-like corona and solar wind source situation, but with weak magnetic fields and associated weak heating. The possibility of a trend in the Sun's current magnetic cycles towards a grand minimum of solar cycles has been suggested. Predictions for Cycle 24 tend to predict a weak maximum and the trend during its rise is tracking along or below the SWPC predicted curve, which has a maximum sunspot count of ~90 in 2013 or 2014. We will attempt to characterize the variations in the heliosphere caused by solar conditions during the declining phase of Cycle 23 through the minimum state and into the rise of Cycle 24. This will include discussion of pertinent results from recent meetings involving solar and stellar magnetic minima and solar cycle variations of solar and heliospheric parameters. Title: Temperature and Extreme-ultraviolet Intensity in a Coronal Prominence Cavity and Streamer Authors: Kucera, T. A.; Gibson, S. E.; Schmit, D. J.; Landi, E.; Tripathi, D. Bibcode: 2012ApJ...757...73K Altcode: We analyze the temperature and EUV line emission of a coronal cavity and surrounding streamer in terms of a morphological forward model. We use a series of iron line ratios observed with the Hinode Extreme-ultraviolet Imaging Spectrograph (EIS) on 2007 August 9 to constrain temperature as a function of altitude in a morphological forward model of the streamer and cavity. We also compare model predictions to the EIS EUV line intensities and polarized brightness (pB) data from the Mauna Loa Solar Observatory (MLSO) Mark 4 K-coronameter. This work builds on earlier analysis using the same model to determine geometry of and density in the same cavity and streamer. The fit to the data with altitude-dependent temperature profiles indicates that both the streamer and cavity have temperatures in the range 1.4-1.7 MK. However, the cavity exhibits substantial substructure such that the altitude-dependent temperature profile is not sufficient to completely model conditions in the cavity. Coronal prominence cavities are structured by magnetism so clues to this structure are to be found in their plasma properties. These temperature substructures are likely related to structures in the cavity magnetic field. Furthermore, we find that the model overestimates the EUV line intensities by a factor of 4-10, without overestimating pB. We discuss this difference in terms of filling factors and uncertainties in density diagnostics and elemental abundances. Title: A porcupine Sun? Implications for the solar wind and Earth Authors: Gibson, Sarah E.; Zhao, Liang Bibcode: 2012IAUS..286..210G Altcode: The recent minimum was unusually long, and it was not just the case of the ``usual story'' slowed down. The coronal magnetic field never became completely dipolar as in recent Space Age minima, but rather gradually evolved into an (essentially axisymmetric) global configuration possessing mixed open and closed magnetic structures at many latitudes. In the process, the impact of the solar wind at the Earth went from resembling that from a sequence of rotating ``fire-hoses'' to what might be expected from a weak, omnidirectional ``lawn-sprinkler''. The previous (1996) solar minimum was a more classic dipolar configuration, and was characterized by slow wind of hot origin localized to the heliospheric current sheet, and fast wind of cold origin emitted from polar holes, but filling most of the heliosphere. In contrast, the more recent minimum solar wind possessed a broad range of speeds and source temperatures (although cooler overall than the prior minimum). We discuss possible connections between these observations and the near-radial expansion and small spatial scales characteristic of the recent minimum's porcupine-like magnetic field. Title: The magnetism and dynamics of solar coronal cavities Authors: Gibson, Sarah Bibcode: 2012cosp...39..618G Altcode: 2012cosp.meet..618G No abstract at ADS Title: Space climate and the recent unusual solar minimum Authors: Gibson, Sarah Bibcode: 2012cosp...39..617G Altcode: 2012cosp.meet..617G Solar minima represent times of low magnetic activity and simple heliospheres. They are thus excellent targets for interdisciplinary, system-wide studies of the origins of solar variability and consequent impacts on planetary systems. The recent solar minimum extended longer and was "quieter" than any we have observed in the Space Age, inspiring both scientific and public interest. It was the lowest and longest minimum in about a century, having weak polar magnetic fields, a complex corona and heliosphere, and recurrent high-speed streams impacting the Earth's space environment. I will review scientific results from Sun to Earth pertaining to the recent minimum, and place these results in a broad context encompassing historical solar and stellar minima, theoretical models of generative dynamo mechanisms, and implications of solar and stellar cyclic behavior for the space climate around planets. Title: Magnetic Structure of Coronal Cavities Authors: Gibson, Sarah; Bak-Steslicka, Urszula; Bethge, Christian; de Toma, Giuliana; Dove, Jim; Fan, Yuhong; Forland, Blake; Rachmeler, Laurel Bibcode: 2012shin.confE.209G Altcode: Coronal cavities are dark, elliptical regions in which strong and twisted magnetism dwells. Polar-crown-prominence cavities in particular are excellent targets for coronal magnetometry, because they are long-lived (on the order of weeks) and extended along the line of sight. Using data from the Coronal Multichannel Polarimeter (CoMP), we show a specific structure in linear polarization that is very consistent from cavity to cavity, and that matches that of a forward-modeled flux rope. We discuss how this structure scales with the size of the cavity, and consider implications for future observations (e.g., ATST and COSMO) in probing and indeed predicting topological changes and instabilities leading up to eruptions. Title: Implications of proton mass flux extremes for solar wind acceleration at cycle minima Authors: Zhao, Liang; Gibson, Sarah E.; Fisk, Lennard A. Bibcode: 2012shin.confE.106Z Altcode: The solar wind proton mass flux, while exhibiting remarkable constancy across heliographic latitudes from pole to equator as measured by the Ulysses spacecraft, nevertheless showed departure from this constancy for some mid-latitude wind in the recent two solar minima. Such departures were most obvious during the 23-24 solar minimum and extended to high heliomagnetic latitudes. We examine the non-transient solar wind (exclusive of Interplanetary Coronal Mass Ejections (ICMEs)) from Ulysses observations in the recent two solar minima, including solar wind magnetic flux, proton mass flux and velocity, and ionic composition O7+/O6+ as an indicator of coronal electron temperature, in order to analyze the solar wind exhibiting extremes in proton mass flux. This study places constraints on models of solar wind acceleration by demonstrating the following properties of extreme (low/high) mass-flux solar wind observed during solar minima: 1) They generally originate in latitudes middle-distant from the heliospheric current sheet (HCS); 2) They have extreme proton density values relative to the rest of the solar wind; 3) They possess a range of velocities and electron temperatures, excluding fast/cold and very slow/hot; 4) They exhibit anticorrelation between electron temperature and proton velocity, as does the rest of the solar wind; 5) They do not follow the anticorrelation trend between proton density and velocity of the rest of the solar wind; and 6) They likewise depart from the trend for the bulk of the wind relating mass flux and the normalized radial component of the heliospheric magnetic field. We discuss the association between these extreme-mass-flux solar wind and mid-latitude coronal holes and 'pseudostreamers'. Title: Stability of Prominence/Cavity Systems Authors: de Toma, Giuliana; Gibson, S.; Forland, B. Bibcode: 2012shin.confE.208D Altcode: Prominence/cavity systems are large scale structures in the solar corona that can live for many weeks and even month and often end their life in the form of large prominence/ cavity eruptions. During this phase of the solar cycle, large coronal cavities are seen at high latitudes and correspond, in on-disk observations, to the polar crown filaments.We investigate the stability of these large prominence/cavity systems in the solar corona and their interaction with the ambient coronal field using observations from SDO/AIA and SDO/HMI. In particular, we examine how the decline with height of the external coronal magnetic field influences the evolution of these systems and their likelihood to erupt.We will present examples of eruptive and non-eruptive coronal cavities. Title: Diagnosing the Prominence-Cavity Connection Authors: Schmit, Donald James; Gibson, Sarah Bibcode: 2012shin.confE.210S Altcode: Prominences and cavities are ubiquitously observed together, but the physical link between these disparate structures has not been established. We address this issue by using dynamic emission in the EUV to probe the connections of these structures. The SDO/AIA observations show that the cavity undergoes strong brightenings in the 171A bandpass. These 171A features take the form of loop-segments which extend from the prominence into the central cavity. Simultaneous and partially-cospatial changes in the prominence form 304A-extensions along the lower regions of these 171A features. The correlated dynamics of both condensed-plasma and coronal-plasma suggest there is a magnetic and energetic connection between the cavity and the prominence. We are now working on explaining the observations in terms of the coronal energy equation, through 1D hydrodynamic and 3D MHD considerations. Title: Cavity morphology in relation to CMEs Authors: Forland, Blake; Gibson, Sarah; Dove, James; Rachmeler, Laurel; Fan, Yuhong Bibcode: 2012shin.confE.204F Altcode: The magnetic field of the corona is the predominate source of energy when it comes to coronal mass ejections (CME) and flares. Coronal prominence cavities are highly visible regions of rarified density when viewed off limb and are often observed erupting into CMEs. A survey was conducted over 19 months of data using the Atmospheric Imaging Assembly (AIA) instrument aboard the Solar Dynamics Observatory (SDO) satellite in order to create a database that could be used to determine correlations between cavity characteristics and CMEs. The first six months of the survey were used for an initial analysis which focused focused on many different cavity characteristics; morphology, aspect ratio, center height and sub structure. The major result showed that cavities with a tear shaped morphology are more likely to erupt. The analysis of aspect ratio also reinforced the use of cavity morphology to describe and characterize cavities. Other characteristics of the analysis were inconclusive, however all characteristics will be used in the continued analysis of all 19 months. Title: Recent Results from the Coronal Multi-Channel Polarimeter Authors: Tomczyk, Steven; Bethge, C.; Gibson, S. E.; McIntosh, S. W.; Rachmeler, L. A.; Tian, H. Bibcode: 2012AAS...22031001T Altcode: The Coronal Multi-Channel Polarimeter (CoMP) instrument is a ground-based filter/polarimeter which can image the solar corona at wavelengths around the emission lines of FeXIII at 1074.7 and 1079.8 nm and the chromospheric emission line of HeI at 1083.0 nm. The instrument consists of a 20-cm aperture coronagraph followed by a Stokes polarimeter and a Lyot birefringent filter with a passband of 0.14 nm width. Both the polarimeter and filter employ liquid crystals for rapid electro-optical tuning. This instrument measures the line-of-sight strength of the coronal magnetic field through the Zeeman effect and the plane-of-sky direction of the magnetic field via resonance scattering. The line-of-sight velocity can also be determined from the Doppler shift. The CoMP has obtained daily observations from the Mauna Loa Solar Observatory for almost one year. We will present recent measurements of the polarization signatures seen with the CoMP and a comparison with models that allow us to constrain coronal structure. We also will present observations of coronal waves taken with the CoMP and discuss their implications for the heating of the solar corona and the acceleration of the solar wind. Title: The Magnetism and Dynamics of Solar Coronal Cavities Authors: Gibson, Sarah Bibcode: 2012AAS...22031002G Altcode: Magnetism defines the complex and dynamic solar corona. We have historically been limited by the difficulty of directly measuring the magnetic fields of the corona, and have turned to observations of coronal plasma to trace out magnetic structure. In some regimes, however, it is the lack of plasma that is a significant indicator of the magnetic field. Such a case is the coronal cavity: a dark, elliptical region in which strong and twisted magnetism dwells. I will elucidate these enigmatic features using observations of coronal cavities in multiple wavelengths and from a variety of observing vantages, and show how magnetic flux rope models provide a self-consistent picture of the cavity, its sub-structure, and its dynamic evolution as a CME. Moreover, I will make use of unprecedented measurements of coronal magnetism, now being obtained by the Coronal Multichannel Polarimeter (CoMP), to demonstrate the presence of twisted magnetic fields within cavities. Title: Morphology Of A Hot Prominence Cavity Observed With Hinode/XRT And SDO/AIA Authors: Weber, Mark A.; Reeves, K. K.; Gibson, S. E.; Kucera, T. A. Bibcode: 2012AAS...22020205W Altcode: Prominence cavities appear as circularly shaped voids in coronal emission over polarity inversion lines where a prominence channel is straddling the solar limb. The presence of chromospheric material suspended at coronal altitudes is a common but not necessary feature within these cavities. These voids are observed to change shape as a prominence feature rotates around the limb. We use a morphological model projected in cross-sections to fit the cavity emission in Hinode/XRT passbands, and then apply temperature diagnostics to XRT and SDO/AIA data to investigate the thermal structure. We find significant evidence that the prominence cavity is hotter than the corona immediately outside the cavity boundary. This investigation follows upon ``Thermal Properties of A Solar Coronal Cavity Observed with the X-ray Telescope on Hinode'' by Reeves et al., 2012, ApJ, in press. M. Weber and K.K. Reeves are supported under contract NNM07AB07C from NASA to SAO. T. Kucera is supported by an award from the NASA SHP Program. Title: Diagnosing the Prominence-Cavity Connection Authors: Schmit, Donald; Gibson, S. Bibcode: 2012AAS...22052102S Altcode: Prominences are regions of cool, dense plasma which are suspended above the solar limb within the much hotter and more rarefied solar corona. The coronal environment surrounding the prominence is often observed as a elliptical region of reduced density (compared to the ambient corona) known as a cavity. To date, the cavity has been a neglected constraint on the prominence system. In this research, I probe the magnetic structural connection between the cavity and prominence and the potential role the cavity plays in the mass and energy balance of the prominence. Observationally, I use the Hinode/EIS and SDO/AIA datasets to extract dynamic substructure from the cavity. The temperature-sensitivities of these data are used to diagnose the interaction of plasma in the prominence and in the surrounding corona.These observational dynamics present a viable constraint on prominence models in two ways. Structurally, the morphology of the extract substructure can be compared to the 3D models of prominence support. Energetically, the spatial and temporal signature of EUV dynamics can be compared to the thermal non-equilibrium model for prominence mass supply. This joint approach systematically addresses the two largest questions in prominence research: how is the prominence mass supported and where does it come from. Title: Temperature Structure of a Coronal Cavity and Streamer Authors: Kucera, Therese A.; Gibson, S. E.; Schmit, D. J.; Landi, E.; Tripathi, D. Bibcode: 2012AAS...22052113K Altcode: We analyze the temperature and EUV line emission of a coronal cavity and surrounding streamer in terms of a morphological forward model. We use a series of iron line ratios observed with the Hinode Extreme-ultraviolet Imaging Spectrograph (EIS) on 2007 Aug. 9 to constrain temperature as a function of altitude in a morphological forward model of the streamer and cavity. We also compare model prediction of the EIS EUV line intensities and polarized brightness (pB) data from the Mauna Loa Solar Observatory (MLSO) MK4. This work builds on earlier analysis using the same model to determine geometry of and density in the same cavity and streamer (Gibson et al. 2010 and Schmit and Gibson 2011). The fit to the data with altitude dependent temperature profiles indicates that both the streamer and cavity have temperatures in the range 1.4-1.7 MK. However, the cavity exhibits substantial substructure such that the altitude dependent temperature profile is not sufficient to completely model conditions in the cavity. This work is supported in part by the NASA SHP program Title: Forward modeling of coronal polarization Authors: Gibson, Sarah E.; Casini, Roberto; Dove, James; Tomczyk, Steve Bibcode: 2012decs.confE...6G Altcode: Coronal polarization measurements from the Coronal Multichannel Polarimeter (CoMP) instrument provide quantitative information about the magnetic field above the solar limb. Inversion of these measurements is difficult due to the optically thin nature of the plasma. Our forward technique can be used with both local and global models to obtain quantitative comparisons between models and observations of the coronal magnetic field. We have used the forward technique to study the magnetic nature of quiescent coronal cavities. We present results from the cavity analysis as well as ways to interpret the coronal polarization data without calculating inversions. Title: Morphology of a Hot Prominence Cavity Observed with XRT and AIA Authors: Weber, Mark; Reeves, Katherine K.; Gibson, Sarah E.; Kucera, Therese A. Bibcode: 2012decs.confE..56W Altcode: Prominence cavities appear as circularly shaped voids in coronal emission over polarity inversion lines where a prominence channel is straddling the solar limb. The presence of chromospheric material suspended at coronal altitudes is a common but not necessary feature within these cavities. These voids are observed to change shape as a prominence feature rotates around the limb. We use a morphological model projected in cross-sections to fit the cavity emission in XRT passbands, and then apply temperature diagnostics to XRT and AIA data to investigate the thermal structure. We find significant evidence that the prominence cavity is hotter than the corona immediately outside the cavity boundary. This investigation follows upon ``Thermal Properties of A Solar Coronal Cavity Observed with the X-ray Telescope on Hinode'' by Reeves et al., 2012, ApJ, in press. M. Weber and K.K. Reeves are supported under contract NNM07AB07C from NASA to SAO. T. Kucera is supported by an award from the NASA SHP Program. Title: Diagnosing the Prominence-Cavity Connection Authors: Schmit, Donald; Gibson, Sarah Bibcode: 2012decs.confE...7S Altcode: Prominences are regions of cool, dense plasma which are suspended above the solar limb within the much hotter and more rarefied solar corona. The coronal environment surrounding the prominence is often observed as an elliptical region of reduced density (compared to the ambient corona) known as a cavity. The fundamental problems in prominence physics are the magnetic support of condensed plasma and the mass-source of those condensations. We use the SDO/AIA dataset to probe the correlated dynamics in between the cool prominence and the coronal cavity. These dynamics are explained through the 1D modeling of the radiative instability. The magnetic field inferred from these dynamics is also compared to the 3D MHD models of prominence support. Through this joint approach, the dynamic nature of the prominence system is brought into sharp focus for the first time. Title: Geomagnetic detection of the sectorial solar magnetic field and the historical peculiarity of minimum 23-24 Authors: Love, Jeffrey J.; Joshua Rigler, E.; Gibson, Sarah E. Bibcode: 2012GeoRL..39.4102L Altcode: 2012GeoRL..3904102L Analysis is made of the geomagnetic-activity aa index covering solar cycle 11 to the beginning of 24, 1868-2011. Autocorrelation shows 27.0-d recurrent geomagnetic activity that is well-known to be prominent during solar-cycle minima; some minima also exhibit a smaller amount of 13.5-d recurrence. Previous work has shown that the recent solar minimum 23-24 exhibited 9.0 and 6.7-d recurrence in geomagnetic and heliospheric data, but those recurrence intervals were not prominently present during the preceding minima 21-22 and 22-23. Using annual-averages and solar-cycle averages of autocorrelations of the historical aa data, we put these observations into a long-term perspective: none of the 12 minima preceding 23-24 exhibited prominent 9.0 and 6.7-d aa recurrence. We show that the detection of these recurrence intervals can be traced to an unusual combination of sectorial spherical-harmonic structure in the solar magnetic field and anomalously low sunspot number. We speculate that 9.0 and 6.7-d recurrence is related to transient large-scale, low-latitude organization of the solar dynamo, such as seen in some numerical simulations. Title: Thermal Properties of a Solar Coronal Cavity Observed with the X-Ray Telescope on Hinode Authors: Reeves, Katharine K.; Gibson, Sarah E.; Kucera, Therese A.; Hudson, Hugh S.; Kano, Ryouhei Bibcode: 2012ApJ...746..146R Altcode: Coronal cavities are voids in coronal emission often observed above high latitude filament channels. Sometimes, these cavities have areas of bright X-ray emission in their centers. In this study, we use data from the X-ray Telescope (XRT) on the Hinode satellite to examine the thermal emission properties of a cavity observed during 2008 July that contains bright X-ray emission in its center. Using ratios of XRT filters, we find evidence for elevated temperatures in the cavity center. The area of elevated temperature evolves from a ring-shaped structure at the beginning of the observation, to an elongated structure two days later, finally appearing as a compact round source four days after the initial observation. We use a morphological model to fit the cavity emission, and find that a uniform structure running through the cavity does not fit the observations well. Instead, the observations are reproduced by modeling several short cylindrical cavity "cores" with different parameters on different days. These changing core parameters may be due to some observed activity heating different parts of the cavity core at different times. We find that core temperatures of 1.75 MK, 1.7 MK, and 2.0 MK (for July 19, July 21, and July 23, respectively) in the model lead to structures that are consistent with the data, and that line-of-sight effects serve to lower the effective temperature derived from the filter ratio. Title: GALFA-HI: A Targeted Search For Star Formation on the Far Side of the Milky Way Authors: Stantzos, Nicholas; Gostisha, M.; Benjamin, R.; Gibson, S.; Koo, B.; Douglas, K. A.; Kang, J.; Park, G.; Peek, J. E. G.; Korpela, E. J.; Heiles, C.; Newton, J. H. Bibcode: 2012AAS...21925211S Altcode: The I-GALFA Survey provides a unique window on the spiral structure of the Milky Way as it contains three coherent 21 cm features that have been identified as spiral arms: the Perseus Arm, the Outer Arm, and the recently discovered Outer Scutum-Centaurus Arm. Moreover, all three of these arms lie beyond the solar circle (although the Perseus arm is thought to cross interior to the solar circle for l< 50 degrees), so this gas does not suffer the kinematic distance ambiguity encountered in the inner Galaxy. We use this data and the CO surveys compiled by Dame et al (2001) to target a search for distant star formation regions seen in the Spitzer Space Telescope/GLIMPSE and WISE mid-infrared all-sky surveys. We characterize the HI arms, and present the star formation regions that may be potentially associated with these three arms. Many of these objects will need spectroscopic follow-up, but some have been previously identified in the Green Bank Telescope HII Region Discovery Survey of Anderson et al (2011). The Inner Galaxy ALFA (I-GALFA) survey is part of the Galactic ALFA HI data set obtained with the Arecibo L-band Feed Array (ALFA) on the Arecibo 305m telescope. Arecibo Observatory is part of the National Astronomy and Ionosphere Center, operated sequentially by Cornell University and Stanford Research Institute under Cooperative Agreement with the U.S. National Science Foundation. Title: The Global Context of Solar Activity During the Whole Heliosphere Interval Campaign Authors: Webb, D. F.; Cremades, H.; Sterling, A. C.; Mandrini, C. H.; Dasso, S.; Gibson, S. E.; Haber, D. A.; Komm, R. W.; Petrie, G. J. D.; McIntosh, P. S.; Welsch, B. T.; Plunkett, S. P. Bibcode: 2011SoPh..274...57W Altcode: The Whole Heliosphere Interval (WHI) was an international observing and modeling effort to characterize the 3-D interconnected "heliophysical" system during this solar minimum, centered on Carrington Rotation 2068, March 20 - April 16, 2008. During the latter half of the WHI period, the Sun presented a sunspot-free, deep solar minimum type face. But during the first half of CR 2068 three solar active regions flanked by two opposite-polarity, low-latitude coronal holes were present. These departures from the quiet Sun led to both eruptive activity and solar wind structure. Most of the eruptive activity, i.e., flares, filament eruptions and coronal mass ejections (CMEs), occurred during this first, active half of the interval. We determined the source locations of the CMEs and the type of associated region, such as active region, or quiet sun or active region prominence. To analyze the evolution of the events in the context of the global solar magnetic field and its evolution during the three rotations centered on CR 2068, we plotted the CME source locations onto synoptic maps of the photospheric magnetic field, of the magnetic and chromospheric structure, of the white light corona, and of helioseismological subsurface flows. Most of the CME sources were associated with the three dominant active regions on CR 2068, particularly AR 10989. Most of the other sources on all three CRs appear to have been associated with either isolated filaments or filaments in the north polar crown filament channel. Although calculations of the flux balance and helicity of the surface magnetic features did not clearly identify a dominance of one region over the others, helioseismological subsurface flows beneath these active regions did reveal a pronounced difference among them. These preliminary results suggest that the "twistedness" (i.e., vorticity and helicity) of subsurface flows and its temporal variation might be related to the CME productivity of active regions, similar to the relationship between flares and subsurface flows. Title: The Sun-Earth Connection near Solar Minimum: Placing it into Context Authors: Bisi, Mario M.; Thompson, Barbara J.; Emery, Barbara A.; Gibson, Sarah E.; Leibacher, John; van Driel-Gesztelyi, Lidia Bibcode: 2011SoPh..274....1B Altcode: No abstract at ADS Title: The solar wind structure and heliospheric magnetic field in the solar Cycle 23-24 minimum and in the increasing phase of Cycle 24 Authors: Gibson, S. E.; Zhao, L.; Fisk, L. A. Bibcode: 2011AGUFMSH31D..05G Altcode: The solar wind structure and the heliospheric magnetic field were substantially different in the latest solar minimum between solar Cycle 23 and 24 from the previous minimum. Compared with the previous minimum, in the latest solar minimum, the heliospheric magnetic field strength was substantially reduced; the streamer-associated-low-temperature solar wind (streamer-stalk wind) was distributed in a narrower region relative to the heliospheric current sheet (HCS); the slow-proton-speed solar wind was scattered in a wider latitudinal region; and there are more large and steady coronal holes at low latitude. We offer an explanation for the decreased magnetic-field strength and the narrowed streamer-stalk wind based on an analysis of the Ulysses and ACE in-situ observations. Solar-wind composition data are used to demonstrate that there are two distinct structures of solar wind: solar wind likely to originate from the stalk of the streamer belt (the highly elongated loops that underlie the HCS), and solar wind from outside this region. The region outside the streamer-stalk region is noticeably larger in the Cycle 23-24 minimum; however, the increased area can account for the reduction in the heliospheric magnetic-field strength in that minimum. Thus, the total magnetic flux contained in this region is the same in the two minima. To have a further understanding of the solar wind structure and its solar source, we ballistically map the ACE in-situ observation back along a radial trajectory from 1 AU to the solar source surface (r = 2.5Rsun) using the observed proton speeds. Then we track the field line from the source surface to the solar surface using a potential-field-source-surface (PFSS) extrapolation model. So the ACE observations, including the heliospheric magnetic field, the solar wind compositional and dynamic properties at 1AU, can be connected to their coronal sources on the solar surface. Synoptic maps showing this connection will be provided, and based on those maps we will further discuss the evolution of the solar wind and coronal structures throughout the latest solar minimum till the increasing phase of the Cycle 24. Title: A Snapshot of the Sun Near Solar Minimum: The Whole Heliosphere Interval Authors: Thompson, Barbara J.; Gibson, Sarah E.; Schroeder, Peter C.; Webb, David F.; Arge, Charles N.; Bisi, Mario M.; de Toma, Giuliana; Emery, Barbara A.; Galvin, Antoinette B.; Haber, Deborah A.; Jackson, Bernard V.; Jensen, Elizabeth A.; Leamon, Robert J.; Lei, Jiuhou; Manoharan, Periasamy K.; Mays, M. Leila; McIntosh, Patrick S.; Petrie, Gordon J. D.; Plunkett, Simon P.; Qian, Liying; Riley, Peter; Suess, Steven T.; Tokumaru, Munetoshi; Welsch, Brian T.; Woods, Thomas N. Bibcode: 2011SoPh..274...29T Altcode: 2011SoPh..tmp..413T We present an overview of the data and models collected for the Whole Heliosphere Interval, an international campaign to study the three-dimensional solar-heliospheric-planetary connected system near solar minimum. The data and models correspond to solar Carrington Rotation 2068 (20 March - 16 April 2008) extending from below the solar photosphere, through interplanetary space, and down to Earth's mesosphere. Nearly 200 people participated in aspects of WHI studies, analyzing and interpreting data from nearly 100 instruments and models in order to elucidate the physics of fundamental heliophysical processes. The solar and inner heliospheric data showed structure consistent with the declining phase of the solar cycle. A closely spaced cluster of low-latitude active regions was responsible for an increased level of magnetic activity, while a highly warped current sheet dominated heliospheric structure. The geospace data revealed an unusually high level of activity, driven primarily by the periodic impingement of high-speed streams. The WHI studies traced the solar activity and structure into the heliosphere and geospace, and provided new insight into the nature of the interconnected heliophysical system near solar minimum. Title: The Whole Heliosphere Interval in the Context of a Long and Structured Solar Minimum: An Overview from Sun to Earth Authors: Gibson, S. E.; de Toma, G.; Emery, B.; Riley, P.; Zhao, L.; Elsworth, Y.; Leamon, R. J.; Lei, J.; McIntosh, S.; Mewaldt, R. A.; Thompson, B. J.; Webb, D. Bibcode: 2011SoPh..274....5G Altcode: 2011SoPh..tmp..427G Throughout months of extremely low solar activity during the recent extended solar-cycle minimum, structural evolution continued to be observed from the Sun through the solar wind and to the Earth. In 2008, the presence of long-lived and large low-latitude coronal holes meant that geospace was periodically impacted by high-speed streams, even though solar irradiance, activity, and interplanetary magnetic fields had reached levels as low as, or lower than, observed in past minima. This time period, which includes the first Whole Heliosphere Interval (WHI 1: Carrington Rotation (CR) 2068), illustrates the effects of fast solar-wind streams on the Earth in an otherwise quiet heliosphere. By the end of 2008, sunspots and solar irradiance had reached their lowest levels for this minimum (e.g., WHI 2: CR 2078), and continued solar magnetic-flux evolution had led to a flattening of the heliospheric current sheet and the decay of the low-latitude coronal holes and associated Earth-intersecting high-speed solar-wind streams. As the new solar cycle slowly began, solar-wind and geospace observables stayed low or continued to decline, reaching very low levels by June - July 2009. At this point (e.g., WHI 3: CR 2085) the Sun-Earth system, taken as a whole, was at its quietest. In this article we present an overview of observations that span the period 2008 - 2009, with highlighted discussion of CRs 2068, 2078, and 2085. We show side-by-side observables from the Sun's interior through its surface and atmosphere, through the solar wind and heliosphere and to the Earth's space environment and upper atmosphere, and reference detailed studies of these various regimes within this topical issue and elsewhere. Title: Cavity magnetic observations: A survey using AIA and CoMP data Authors: Forland, B.; Rachmeler, L. A.; Gibson, S. E.; Dove, J. Bibcode: 2011AGUFMSH43B1951F Altcode: The magnetic structure of the corona is the predominate source of energy when it comes to coronal mass ejections (CMEs) and flares. Coronal prominence cavities are highly visible regions of rarified density when viewed off limb that are are known to store magnetic energy and can erupt causing CMEs. Observing magnetic fields in the corona has always been difficult, but for the first time daily observations of linear polarization are being made by the Coronal Multichannel Polarimeter (CoMP). These observations of the optically-thin corona are ideal for structure such as cavities which extend along the line of sight. A survey was conducted over the last 6 months using the Atmospheric Imaging Assembly (AIA) instrument aboard the Solar Dynamic Observatory (SDO) satellite in order to create a working database of all visible cavities. These cavities were then compared to intensity and linear polarization images obtained by the CoMP telescope. The linear polarization images were examined for specific structures similar to those created using forward calculations of CoMP-like observables from magnetohydrodynamic models. Title: Diagnosing the Prominence-Cavity Connection Authors: Schmit, D. J.; Gibson, S. E. Bibcode: 2011AGUFMSH43B1947S Altcode: The magnetic field is thought to play a central role in both the support of prominence plasma as well as the thermodynamic isolation of the surrounding cavity. We use the statistical goldmine of the SDO/AIA dataset to probe for the first time the dynamical link between these related structures. These observations are compared to the 3D magnetic geometries predicted by MHD models. The dynamic features are explained within the context of 1D field-aligned momentum and energy imbalance. Title: Comparing Global Coronal Models to CoMP Data Authors: Rachmeler, L. A.; Gibson, S. E.; Tomczyk, S. Bibcode: 2011AGUFMSH43B1941R Altcode: Coronal polarization data is one of the very few available quantitative measurements of the coronal magnetic field, which makes it extremely attractive as a means of validating numerical models. Our forward analysis technique produces synthetic line-of-sight integrated polarization signals from coronal models. We present initial results from comparisons of forward calculations of the Potential Field Source Surface (PFSS) model to polarization data taken with the Coronal Multichannel Polarimeter (CoMP). This research focuses on validating the applicability of the PFSS model by determining how much the real corona deviates from a potential field. The non-potentiality of the corona not only has applications for testing the PFSS field, but also for forecasting, and for finding the locations of greatest magnetic energy storage. Title: Solar Prominence Eruptions and CMEs at the Start of Cycle 24 Authors: de Toma, Giuliana; Gibson, S.; Burkepile, J.; Fan, Y.; Reinard, A. Bibcode: 2011shin.confE.147D Altcode: We present the analysis of prominence eruptions and CMEs during the rising phase of cycle 24. We combine data from the two STEREO and SDO spacecraft (that are near quadrature) to observe simultaneously the region where a CME originates and the CME moving outward in the plane-of-the-sky. This allows us to compute trajectories for the CME and the associated eruptive prominence and, at the same time, to study the on-disk CME manifestations such as flares, dimming regions, and coronal waves with high spatial and temporal resolution. Title: Learning about coronal polarization through forward modeling Authors: Rachmeler, Laurel Anne; Gibson, Sarah; Dove, James Bibcode: 2011shin.confE..30R Altcode: We present scientific results from forward modeling of coronal polarization signals whereby synthetic data is created from coronal models. We have worked with spheromak and cylindrical-type flux ropes, and breakout-type sheared arcade. Each of these magnetic configurations produces distinct polarization signatures. We present the results from our analysis as well as some of the challenges that we have faced, and the insight we have gained during the analysis. The goal is to present the scientific utility as well as the limitations of coronal polarization data. Title: A Ring of Polarized Light: Evidence for Twisted Coronal Magnetism in Cavities Authors: Gibson, Sarah; Dove, James; Rachmeler, Laurel; Tomczyk, Steve; Judge, Phil Bibcode: 2011shin.confE..28G Altcode: Coronal prominence cavities may be manifestations of twisted or sheared magnetic fields capable of storing the energy required to drive solar eruptions. The Coronal Multi-Channel Polarimeter (CoMP), recently installed at Mauna Loa Solar Observatory, can measure polarimetric signatures of current-carrying magnetohydrodynamic (MHD) systems. For the first time, this instrument offers the capability of daily full-Sun observations of the forbidden lines of Fe XIII with high enough spatial resolution and throughput to measure polarimetric signatures of current-carrying MHD systems. By forward-calculating CoMP observables from analytic MHD models of spheromak-type magnetic flux ropes, we show that a predicted observable for such flux ropes oriented along the line of sight is a bright ring of linear polarization surrounding a region where the linear polarization strength is relatively depleted. We present CoMP observations of a coronal cavity possessing such a polarization ring. Title: Vector Tomography for the 3D Coronal Magnetic Field with CoMP Authors: Kramar, Maxim; Lin, Haosheng; Inhester, Bernd; Gibson, Sarah Bibcode: 2011shin.confE..29K Altcode: Magnetic fields in the solar corona dominates the gas pressure and therefore determine the static and dynamic properties of the corona. Direct measurement of the coronal magnetic field is one of the most challenging problems in observational solar astronomy and recently a significant progress has been achieved here with deployment of the HAO Coronal Multichannel Polarimeter (CoMP). The instrument provides polarization measurements of Fe XIII 10747 A forbidden line emission. The observed polarization depends on magnetic field through the Hanle and Zeeman effects. However, because the coronal measurements are integrated over line-of-site (LOS), it is impossible to derive the configuration of the coronal magnetic field from a single observation (from a single viewing direction). The vector tomography techniques based on measurements from several viewing directions has the potential to resolve the 3D coronal magnetic field structure over LOS. Because of the non-linear character of the Hanle effect, the reconstruction result based on such data is not straightforward and depends on the particular coronal field configuration. Therefore we study here what is the sensitivity of the vector tomographic inversion to sophisticated (MHD) coronal magnetic field models.

For several important cases of magnetic field configuration, it has been found that even just Stokes-Q and -U data (supplied with 3D coronal density and temperature) can be used in vector tomography to provide a realistic 3D coronal magnetic field configuration. Effect of noise in the all input data has been also studied. Inclusion of the Stokes-V data into the inversion will significantly increase a number of of magnetic field configuration which are possible to reconstruct.

Particularly, the reconstructions may be used to analyze non-potential pre-CME magnetic configurations or for improving a potential field model when the field is potential. Title: Forward Modeling Cavity Density: A Multi-instrument Diagnostic Authors: Schmit, D. J.; Gibson, S. E. Bibcode: 2011ApJ...733....1S Altcode: The thermodynamic properties of coronal prominence cavities present a unique probe into the energy and mass budget of prominences. Using a three-dimensional morphological model, we forward model the polarization brightness and extreme-ultraviolet (EUV) emission of a cavity and its surrounding streamer. Using a genetic algorithm, we find the best-fit density model by comparing the models to Mauna Loa Solar Observatory MK4 and Hinode EUV Imaging Spectrometer data. The effect of temperature variations on the derived density is also measured. We have measured the density inside a cavity down to 1.05 R sun with height-dependent error bars. Our forward modeling technique compensates for optically thin projection effects. This method provides a complementary technique to traditional line ratio diagnostics that is useful for diffuse off-limb coronal structures. Title: Temperature Structure of a Coronal Cavity Authors: Kucera, Therese A.; Gibson, S. E.; Schmit, D. J. Bibcode: 2011SPD....42.1833K Altcode: 2011BAAS..43S.1833K We analyze the temperature structure of a coronal cavity observed in Aug. 2007. Coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and X-rays. When these structures erupt they form the cavity portions of CMEs. It is important to establish the temperature structure of cavities in order to understand the thermodynamics of cavities in relation to their three-dimensional magnetic structure.

To analyze the temperature we compare temperature ratios of a series of iron lines observed by the Hinode/EUV Imaging Spectrometer (EIS). We also use those lines to constrain a forward model of the emission from the cavity and streamer. The model assumes a coronal streamer with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. Temperature and density can be varied as a function of altitude both in the cavity and streamer. The general cavity morphology and the cavity and streamer density have already been modeled using data from STEREO's SECCHI/EUVI and Hinode/EIS (Gibson et al 2010 and Schmit & Gibson 2011). Title: Vector Tomography Based on Hanle and Zeeman Effects Observed from Ecliptic Plane Authors: Kramar, Maxim; Lin, H.; Gibson, S. Bibcode: 2011SPD....42.1830K Altcode: 2011BAAS..43S.1830K The magnetically sensitive coronal emission lines provide information about coronal magnetic field via Hanle and Zeeman effects. As the measured emission are integrated over line-of-sight, the vector tomography must be used for deriving 3D magnetic field configuration. The unique solution for any field configuration exists when observations are done from both ecliptic and out of ecliptic plane and supplied by photospheric magnetic field measurements. When observations are only from the ecliptic plane, the number of field configurations which are possible to reconstruct are reduced. We study here what types of coronal magnetic field configurations can be reconstructed based on Hanle and Zeeman effects provided by CoMP and SOLARC instruments. Effect of noise in the data and uncertainty in 3D reconstruction of the coronal density and temperature are also studied. Title: A Ring of Polarized Light: Evidence for Twisted Coronal Magnetism in Cavities Authors: Dove, J. B.; Gibson, S. E.; Rachmeler, L. A.; Tomczyk, S.; Judge, P. Bibcode: 2011ApJ...731L...1D Altcode: Coronal prominence cavities may be manifestations of twisted or sheared magnetic fields capable of storing the energy required to drive solar eruptions. The Coronal Multi-Channel Polarimeter (CoMP), recently installed at Mauna Loa Solar Observatory, can measure polarimetric signatures of current-carrying magnetohydrodynamic (MHD) systems. For the first time, this instrument offers the capability of daily full-Sun observations of the forbidden lines of Fe XIII with high enough spatial resolution and throughput to measure polarimetric signatures of current-carrying MHD systems. By forward-calculating CoMP observables from analytic MHD models of spheromak-type magnetic flux ropes, we show that a predicted observable for such flux ropes oriented along the line of sight is a bright ring of linear polarization surrounding a region where the linear polarization strength is relatively depleted. We present CoMP observations of a coronal cavity possessing such a polarization ring. Title: The GALFA-HI Survey: Feeding the Disk via Stellar Feedback Authors: Putman, Mary E.; Peek, J.; Saul, D.; Grcevich, J.; Begum, A.; Douglas, K.; Gibson, S.; Heiles, C.; Korpela, E.; Lee, M.; Stanimirovic, S. Bibcode: 2011AAS...21724101P Altcode: 2011BAAS...4324101P The contribution of future star formation fuel to a galaxy from evolved stars remains uncertain. We present a correlation of discrete clouds of HI gas with evolved variable stars and find a number of cases where stellar mass-loss is likely to have created the cloud. The results of this study impact our understanding of both stellar outflows and galactic gas recycling. This research was partially funded by NSF grant AST-0917810. Title: The GALFA-HI Survey: Transition from HI to H2 Caught in Action in the Perseus Molecular Cloud Authors: Lee, Min-Young; Stanimirovic, S.; Leroy, A.; Douglas, K.; Di Francesco, J.; Gibson, S.; Knee, L.; Plume, R.; Begum, A.; Grcevich, J.; Heiles, C.; Korpela, E.; Peek, J.; Pingel, N.; Putman, M.; Saul, D. Bibcode: 2011AAS...21724102L Altcode: 2011BAAS...4324102L The conversion of atomic gas into molecular gas is a critical process for star formation. Yet, a deep understanding of fundamental agents that control the ratio of atomic to molecular gas in molecular clouds has not been achieved.

Recently, Krumholz et al. (2009) provided theoretical predictions for the ratio of atomic to molecular gas in galaxies as a function of galactic properties (total gas column density and metallicity). We test the Krumholz's predictions on sub-parsec scales by investigating the ratio of atomic to molecular gas across the Perseus molecular cloud. We estimate the dust column density using the IRIS 60 and 100 micron maps and derive the H2 column density from the excess of infrared emission relative to the HI column density. Using the HI data from the GALFA-HI Survey, we derive the map of RH2 (H2 surface density / HI surface density) for Perseus. Our comparison of observational data with the Krumholz's predictions shows that the model reasonably well describes RH2 as a function of total gas column density even at sub-parsec scales. We compare RH2 for several star-forming and dark clouds in Perseus to investigate the role of interstellar radiation field in molecule formation.

This research was partially funded by the NSF grant

AST-0707679 and the Research Corporation for Science Advancement. Title: Three-dimensional morphology of a coronal prominence cavity Authors: Gibson, S. E.; Kucera, T. A.; Rastawicki, D.; Dove, J.; de Toma, G.; Hao, J.; Hill, S. M.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Rachmeler, L.; Reeves, K. K.; Schmieder, B.; Schmit, D. J.; Sterling, A.; Tripathi, D.; Williams, D. R.; Zhang, M. Bibcode: 2010AGUFMSH51A1667G Altcode: We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths from radio to soft-X-ray to integrated white light. From these data it is clear that the prominence cavity is the limb manifestation of a longitudinally-extended polar-crown filament channel, and that the cavity is a region of low density relative to the surrounding corona. As a first step towards quantifying density and temperature from campaign spectroscopic data, we establish the three-dimensional morphology of the cavity. This is critical for taking line-of-sight projection effects into account, since cavities are not localized in the plane of the sky and the corona is optically thin. We have augmented a global coronal streamer model to include a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. We have developed a semi-automated routine that fits ellipses to cross-sections of the cavity as it rotates past the solar limb, and have applied it to Extreme Ultraviolet Imager (EUVI) observations from the two Solar Terrestrial Relations Observatory (STEREO) spacecraft. This defines the morphological parameters of our model, from which we reproduce forward-modeled cavity observables. We find that cavity morphology and orientation, in combination with the viewpoints of the observing spacecraft, explains the observed variation in cavity visibility for the east vs. west limbs. Title: Three-dimensional Morphology of a Coronal Prominence Cavity Authors: Gibson, S. E.; Kucera, T. A.; Rastawicki, D.; Dove, J.; de Toma, G.; Hao, J.; Hill, S.; Hudson, H. S.; Marqué, C.; McIntosh, P. S.; Rachmeler, L.; Reeves, K. K.; Schmieder, B.; Schmit, D. J.; Seaton, D. B.; Sterling, A. C.; Tripathi, D.; Williams, D. R.; Zhang, M. Bibcode: 2010ApJ...724.1133G Altcode: We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths from radio to soft X-ray to integrated white light. From these data it is clear that the prominence cavity is the limb manifestation of a longitudinally extended polar-crown filament channel, and that the cavity is a region of low density relative to the surrounding corona. As a first step toward quantifying density and temperature from campaign spectroscopic data, we establish the three-dimensional morphology of the cavity. This is critical for taking line-of-sight projection effects into account, since cavities are not localized in the plane of the sky and the corona is optically thin. We have augmented a global coronal streamer model to include a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. We have developed a semi-automated routine that fits ellipses to cross-sections of the cavity as it rotates past the solar limb, and have applied it to Extreme Ultraviolet Imager observations from the two Solar Terrestrial Relations Observatory spacecraft. This defines the morphological parameters of our model, from which we reproduce forward-modeled cavity observables. We find that cavity morphology and orientation, in combination with the viewpoints of the observing spacecraft, explain the observed variation in cavity visibility for the east versus west limbs. Title: A ring of polarized light: evidence for twisted coronal magnetism in cavities (Invited) Authors: Dove, J.; Rachmeler, L.; Gibson, S. E.; Judge, P. G.; Tomczyk, S. Bibcode: 2010AGUFMSH54A..01D Altcode: Determining coronal magnetic fields is crucial to modeling the processes that power and trigger solar flares and coronal mass ejections. Coronal prominence cavities have been modeled as magnetic flux ropes, and have been observed to erupt bodily as coronal mass ejections. One promising technique for establishing the magnetic morphology of cavities is to use spectropolarimetry of the infrared (IR) forbidden lines of Fe XIII (at 1074.7 nm and 1079.8 nm). The Coronal Multi-Channel Polarimeter is currently situated at the Mauna Loa Solar Observatory (MLSO), and has begun taking daily full-Sun observations of line-of-sight integrated Stokes parameters for these lines. For a variety of analytic coronal magnetohydrodynamic models, we have determined forward-calculations of CoMP observables using the formalism of Judge and Casini (2001). We show that different MHD models and orientations do yield distinguishing observational characteristics. In particular, a common characteristic for spheroidal flux ropes oriented along the observational line of sight is a ring of linear polarization surrounding a region where the linear polarization strength is relatively depleted (the heart of darkness). Such a polarization ring has been found in an observation of a coronal cavity taken by CoMP in April 2005 from Sacramento Peak. Cavities are ubiquitous features, particularly at this time of the solar cycle. The daily observations to be taken by CoMP at MLSO will allow us to further probe these structures, constraining models of coronal magnetism and providing a testbed for future capabilities of the proposed Coronal Solar Magnetism Observatory (COSMO). Title: 3D Study of Solar Eruptions Using SDO and STEREO Observations Authors: de Toma, G.; Reinard, A. A.; Gibson, S. E.; Burkepile, J.; Fan, Y.; Torok, T. Bibcode: 2010AGUFMSH23A1834D Altcode: Combination of data from the recently launched SDO and the two STEREO spacecraft -that are now at about 80deg from the Sun-Earth direction- offers the unprecedented opportunity to observe simultaneously the region where a CME originates and the CME moving outward in the plane-of-the-sky. This allows us to compute trajectories for the CME and the associated eruptive prominence and, at the same time, to study the on-disk CME manifestations such as flares, dimming regions, and coronal waves with very high spatial and temporal resolution. We present examples of Earth-directed CMEs, when the CME can be traced from the Sun to the Earth, that take advantage of this unique satellite configuration. Title: Space Based Observations of Coronal Cavities in Conjunction with the Total Solar Eclipse of July 2010 Authors: Kucera, T. A.; Berger, T. E.; Boerner, P.; Dietzel, M.; Druckmuller, M.; Gibson, S. E.; Habbal, S. R.; Morgan, H.; Reeves, K. K.; Schmit, D. J.; Seaton, D. B. Bibcode: 2010AGUFMSH51A1666K Altcode: In conjunction with the total solar eclipse on July 11, 2010 we coordinated a campaign between ground and space based observations. Our specific goal was to augment the ground based measurement of coronal prominence cavity temperatures made using iron lines in the IR (Habbal et al. 2010 ApJ 719 1362) with measurements performed by space based instruments. Included in the campaign were Hinode/EIS, XRT and SOT, PROBA2/SWAP, SDO/AIA, SOHO/CDS and STEREO/SECCHI/EUVI, in addition to the ground based IR measurements. We plan to use a combination of line ratio and forward modeling techniques to investigate the density and temperature structure of the cavities at that time. Title: Morphology of a hot coronal cavity core as observed by Hinode/XRT Authors: Reeves, K. K.; Gibson, S. E.; Kucera, T. A.; Hudson, H. S. Bibcode: 2010AGUFMSH51A1669R Altcode: We follow a coronal cavity that was observed by Hinode/XRT during the summer of 2008. This cavity has a persistent area of relatively bright X-ray emission in its center. We use multifilter data from XRT to study the thermal emission from this cavity, and find that the bright center is hotter than the surrounding cavity plasma with temperatures of about 1.6 MK. We follow the morphology of this hot feature as the cavity structure rotates over the limb during the several days between July 19 - 23 2008. We find that the hot structure at first looks fairly circular, then appears to expand and elongate, and then shrinks again to a compact circular shape. We interpret this apparent change in shape as being due to the morphology of the filament channel associated with the cavity, and the change in viewing angle as the structure rotates over the limb of the Sun. Title: Density Diagnostics in Cavities: Incorporating and Bypassing Projection Effects Authors: Schmit, D. J.; Gibson, S. E.; Kucera, T. A. Bibcode: 2010AGUFMSH51A1668S Altcode: The highly ionized corona emits strongly in EUV atomic emission lines. Comparison of relative emission in various lines provides the temperature and density of the coronal plasma. We use an Fe XII line ratio to probe the density of a prominence cavity at heights generally only accessible to spectroscopic instruments. We take a novel approach in this diagnostic by fully accounting for the 3D structure of the corona so as to compensate for the projection effects in optical thin emission. The density inside the cavity and the streamer are constrained using a forward model where in emission is synthesized with CHIANTI. The synthetic emission and scattering is compared to Hinode/EIS and MLSO MKIV data. A least squares minimization is conducted using a genetic algorithm. In particular, this work addresses the degree to which we can answer the question, “Is there a density jump at all heights?”. Title: Creating synthetic coronal observational data from MHD models: the forward technique Authors: Rachmeler, L. A.; Gibson, S. E.; Dove, J.; Kucera, T. A. Bibcode: 2010AGUFMSH31A1786R Altcode: We present a generalized forward code for creating simulated coronal observables off the limb from numerical and analytical MHD models. This generalized forward model is capable of creating emission maps in various wavelengths for instruments such as Hinode/XRT, STEREO/SECCHI/EUVI, and coronagraphs, as well as spectropolarimetric images and line profiles. The inputs to our code can be analytic MHD or morphological models (of which four come with the code) or 2.5D and 3D numerical datacubes. We present some examples of the observable data created with our code as well as its functional capabilities. This code is currently available for beta-testing (contact authors), with the ultimate goal of release as a SolarSoft package. Title: Whole Heliosphere Interval: Overview of JD16 Authors: Webb, David F.; Gibson, Sarah E.; Thompson, Barbara J. Bibcode: 2010HiA....15..471W Altcode: The Whole Heliosphere Interval is an international observing and modeling effort to characterize the three-dimensional interconnected solar-heliospheric-planetary system, i.e., the “heliophysical” system. WHI was part of the International Heliophysical Year, on the 50th anniversary of the International Geophysical Year, and benefited from hundreds of observatories and instruments participating in IHY activities. WHI describes the 3-D heliosphere originating from solar Carrington Rotation 2068, March 20-April 16, 2008. The focus of IAU JD16 was on analyses of observations obtained during WHI, and simulations and modeling involving those data and that period. Consideration of the WHI interval in the context of surrounding solar rotations and/or compared to last solar minimum was also encouraged. Our goal was to identify connections and commonalities between the various regions of the heliosphere. Title: Forward modeling of spectropolarimetric data to interpret coronal magnetic features Authors: Rachmeler, Laurel A.; Gibson, S. E.; Dove, J.; Judge, P. G. Bibcode: 2010shin.confE..53R Altcode: We present a forward model that creates various forms of coronal observational data from simulated systems. Along with plane of sky parameter slices and integrated emission images, this model calculates the full Stokes vectors from forbidden infrared lines. It is clear that photospheric magnetograph data is not sufficient to ascertain coronal magnetic fields. The coronal Stokes vectors provide additional information about the magnetic morphology above the solar limb, specifically the relative strength of the integrated plane of sky and line of sight field. Our forward model helps to determine which physical features can be identified in the observations as a specific component of a theoretical model, without requiring a full 3D inversion of the Stokes profiles. We have found that flux ropes are theoretically identifiable in the simulated data, and we use this technique to explore the disambiguation of pre-CME filament structure. Title: The Whole Heliosphere Interval in the Context of the Current Solar Minimum Authors: Gibson, S. E.; Webb, D. F.; Thompson, B. J. Bibcode: 2010ASPC..428..223G Altcode: The current solar minimum may not be "peculiar" when considered on scales of a century or more. However, the opportunity for discovery yielded by its extended nature, in combination with the abundance of modern observations, cannot be overstated. In this paper, we describe the Whole Heliosphere Interval (WHI), an in-depth study of the Sun-Earth system for a solar rotation in March/April 2008. We discuss how WHI fits within the broader context of the current deep, long, and complex solar minimum. Title: The Minimum Between Cycle 23 and 24: Is Sunspot Number the Whole Story? Authors: de Toma, G.; Gibson, S. E.; Emery, B. A.; Arge, C. N. Bibcode: 2010ASPC..428..217D Altcode: During recent years we have observed a long and deep solar minimum with sunspot number in 2008 and 2009 reaching the lowest level in about a century. In spite of the lack of sunspot activity at the Sun, observations have shown that a relatively complex corona and heliosphere persisted for most of the minimum phase. The solar corona did not reach the simple "dipolar" shape often seen during solar minima, while low-latitude coronal holes, and their associated corotating high-speed solar wind streams, persisted to 2008, modulating the solar wind. We compare the current and previous minima to show how, even during very quiet times, different magnetic configurations are possible at the Sun and discuss how these different morphologies can affect the corona, heliosphere, and even the geospace. Title: Thermal Properties of Coronal Cavities as Observed by the X-Ray Telescope on Hinode Authors: Reeves, Kathy; Gibson, S. E.; Kucera, T. A.; Hudson, H. S.; Tripathi, D. Bibcode: 2010AAS...21640511R Altcode: 2010BAAS...41..891R Coronal cavities are voids in coronal emission often observed above high latitude filament channels. Sometimes, these cavities have areas of bright X-ray emission in their centers (i.e. Hudson et al

1999). In this study, we use data from the X-ray Telescope (XRT) on Hinode to examine the thermal emission properties of two kinds of coronal cavities, those with and without enhanced emission at their centers. For cavities with bright X-ray emission in their centers, we find evidence for elevated temperatures in the cavity center. We find no obvious correlation between the presence of

bright cavity cores and filament presence or eruption.

This work is part of the effort of the International Space Science Institute International Team on Prominence Cavities Title: Geometric Model of a Coronal Cavity Authors: Kucera, Therese A.; Gibson, S. E.; Rastawicki, D.; Dove, J.; de Toma, G.; Hao, J.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Reeves, K. K.; Schmidt, D. J.; Sterling, A. C.; Tripathi, D. K.; Williams, D. R.; Zhang, M. Bibcode: 2010AAS...21640510K Altcode: 2010BAAS...41..890K We observed a coronal cavity from August 8-18 2007 during a multi-instrument observing campaign organized under the auspices of the International Heliophysical Year (IHY). Here we present initial efforts to model the cavity with a geometrical streamer-cavity model. The model is based the white-light streamer model of Gibson et al. (2003), which has been enhanced by the addition of a cavity and the capability to model EUV and X-ray emission. The cavity is modeled with an elliptical cross-section and Gaussian fall-off in length and width inside the streamer. Density and temperature can be varied in the streamer and cavity and constrained via comparison with data. Although this model is purely morphological, it allows for three-dimensional, multi-temperature analysis and characterization of the data, which can then provide constraints for future physical modeling. Initial comparisons to STEREO/EUVI images of the cavity and streamer show that the model can provide a good fit to the data. This work is part of the effort of the International Space Science Institute International Team on Prominence Cavities. Title: Solar Cycle 23: An Unusual Solar Minimum? Authors: de Toma, Giuliana; Gibson, Sarah; Emery, Barbara; Kozyra, Janet Bibcode: 2010AIPC.1216..667D Altcode: We are currently observing the minimum phase of Cycle 23. Magnetic activity during the years 2006-2009 has been very weak with sunspot numbers reaching the lowest values in about 100 years. This long and extended minimum is characterized by weak polar magnetic fields, small polar coronal holes, and a relatively complex coronal morphology. This magnetic configuration at the Sun is remarkably different from the one observed during the previous two solar minima. We review observations made at the Sun and in the solar wind during the recent solar minima and discuss the implications of the observed differences for the heliosphere and geospace. Title: If the Sun is so quiet, why is the Earth ringing? A comparison of two solar minimum intervals Authors: Gibson, S. E.; Kozyra, J. U.; de Toma, G.; Emery, B. A.; Onsager, T. G.; Thompson, B. J. Bibcode: 2009AGUFMSH11A1501G Altcode: A system-oriented analysis of new observations from the recent international Whole Heliosphere Interval (WHI) campaign in comparison with the equivalent Whole Sun Month (WSM) campaign from last cycle’s minimum yields new insight into solar quiet intervals and the solar minimum Sun-Earth system. We use a side-by-side comparison of these two intervals to demonstrate that sunspot numbers, while providing a good measure of solar activity, do not provide sufficient information to gauge solar and heliospheric magnetic complexity and its effect at the Earth. The present solar minimum is exceptionally quiet, with sunspot numbers the lowest in 75 years, solar wind density and IMF strength at the lowest values ever observed, and geomagnetic indices and solar EUV fluxes the lowest in three solar cycles. Despite, or perhaps because of this global weakness in the heliospheric magnetic field, large near-equatorial coronal holes lingered even as the sunspots disappeared, indicating significant open magnetic flux at low latitudes. Consequently, for the months surrounding the WHI campaign, strong, long, and recurring high-speed streams in the solar wind intercepted the Earth in contrast to the weaker and more sporadic streams that occurred around the time of the WSM campaign. Since the speed, duration and southward magnetic field component in wind streams determine the severity of space weather effects, the geospace environment responded quite differently to the two solar minimum heliospheric morphologies. We illustrate this point with the behavior of relativistic electrons in the Earth’s outer radiation belt, which were more than three times stronger during WHI than in WSM. The cause is clear: it is well-known that high-speed streams drive radiation belt population, and indeed, for the months surrounding WHI, geospace and upper atmospheric parameters were ringing with the periodicities of the solar wind in a manner that was absent last cycle minimum. Such behavior could not have been predicted using sunspot numbers alone, indicating the importance of considering variation within and between solar minima in analyzing and predicting space weather responses at the Earth during solar quiet intervals, as well as in interpreting the Sun’s past behavior as preserved in geological and historical records. Title: Are Unusual Solar Wind Conditions in SC23-24 Triggering Changes in the Geospace Response to High Speed Streams? (Invited) Authors: Kozyra, J. U.; Brandt, P. C.; Buzulukova, N.; de Zeeuw, D.; Fok, M. H.; Frey, H. U.; Gibson, S. E.; Ilie, R.; Liemohn, M. W.; Mende, S. B.; Paxton, L. J.; Rastaetter, L.; Ridley, A. J.; Thomsen, M. F. Bibcode: 2009AGUFMSH14A..06K Altcode: In the descent to solar minimum in solar cycle 23-24, the high-speed streams (HSS) were faster and longer lived than previous cycles but the average IMF was weaker and the average solar wind density lower than ever before recorded upstream of the Earth. A simulation of high speed stream activity on 22-24 January 2005 using the BATS-R-US MHD model with embedded Rice Convection Model driven by solar wind inputs indicates that, at least for this event, the interaction between high speed streams and the magnetosphere has been modified by these unusual solar wind conditions. Northward IMF in the HSS drove the periodic capture of solar wind/magnetosheath plasma in the dayside magnetosphere due to high-latitude reconnection. At times of observed strong periodic auroral activity, a significant IMF By component produced a magnetospheric sash configuration in the simulations in which fingers of enhanced plasma beta were associated with strong field-aligned currents linking to the nightside auroral region. In agreement with the simulations, IMAGE HENA observed low energy (less than tens of keV) hydrogen energetic neutral atoms peaking on the dayside for the 3-days of the high speed stream activity. IMAGE FUV and TIMED GUVI observed periodic auroral activations during the HSS that resembled poleward boundary intensifications (PBIs) rather than the periodic substorms typically associated with HSS. The locations of the observed PBIs in the southern hemisphere were consistent with the high-beta fingers in the near-Earth plasma sheet predicted by the simulation. Particle injection signatures at LANL geosynchronous satellites accompanied the PBIs. To our knowledge, these results provide the first evidence in support of the role of northward IMF in HSS interactions. Based on these results, a study of energetic neutral atom images from TWINS and IMAGE HENA along with observations from other missions in the Heliophysics System Observatory is underway to determine if these characteristics are typical of HSS interactions in the current unusual solar minimum and to search for consequences throughout geospace. Title: If the Sun is so quiet, why is the Earth ringing? A comparison of two solar minimum intervals Authors: Gibson, S. E.; Kozyra, J. U.; de Toma, G.; Emery, B. A.; Onsager, T.; Thompson, B. J. Bibcode: 2009JGRA..114.9105G Altcode: 2009JGRA..11409105G Observations from the recent Whole Heliosphere Interval (WHI) solar minimum campaign are compared to last cycle's Whole Sun Month (WSM) to demonstrate that sunspot numbers, while providing a good measure of solar activity, do not provide sufficient information to gauge solar and heliospheric magnetic complexity and its effect at the Earth. The present solar minimum is exceptionally quiet, with sunspot numbers at their lowest in 75 years and solar wind magnetic field strength lower than ever observed. Despite, or perhaps because of, a global weakness in the heliospheric magnetic field, large near-equatorial coronal holes lingered even as the sunspots disappeared. Consequently, for the months surrounding the WHI campaign, strong, long, and recurring high-speed streams in the solar wind intercepted the Earth in contrast to the weaker and more sporadic streams that occurred around the time of last cycle's WSM campaign. In response, geospace and upper atmospheric parameters continued to ring with the periodicities of the solar wind in a manner that was absent last cycle minimum, and the flux of relativistic electrons in the Earth's outer radiation belt was elevated to levels more than three times higher in WHI than in WSM. Such behavior could not have been predicted using sunspot numbers alone, indicating the importance of considering variation within and between solar minima in analyzing and predicting space weather responses at the Earth during solar quiet intervals, as well as in interpreting the Sun's past behavior as preserved in geological and historical records. Title: Additive Self-helicity as a Kink Mode Threshold Authors: Malanushenko, A.; Longcope, D. W.; Fan, Y.; Gibson, S. E. Bibcode: 2009ApJ...702..580M Altcode: 2009arXiv0909.4959M In this paper, we propose that additive self-helicity, introduced by Longcope and Malanushenko, plays a role in the kink instability for complex equilibria, similar to twist helicity for thin flux tubes. We support this hypothesis by a calculation of additive self-helicity of a twisted flux tube from the simulation of Fan and Gibson. As more twist gets introduced, the additive self-helicity increases, and the kink instability of the tube coincides with the drop of additive self-helicity, after the latter reaches the value of HA /Φ2 ≈ 1.5 (where Φ is the flux of the tube and HA is the additive self-helicity). We compare the additive self-helicity to twist for a thin subportion of the tube to illustrate that HA /Φ2 is equal to the twist number, studied by Berger and Field, when the thin flux tube approximation is applicable. We suggest that the quantity HA /Φ2 could be treated as a generalization of a twist number, when the thin flux tube approximation is not applicable. A threshold on a generalized twist number might prove extremely useful studying complex equilibria, just as the twist number itself has proven useful studying idealized thin flux tubes. We explicitly describe a numerical method for calculating additive self-helicity, which includes an algorithm for identifying a domain occupied by a flux bundle and a method of calculating potential magnetic field confined to this domain. We also describe a numerical method to calculate twist of a thin flux tube, using a frame parallelly transported along the axis of the tube. Title: A Survey of Coronal Cavity Density Profiles Authors: Fuller, J.; Gibson, S. E. Bibcode: 2009ApJ...700.1205F Altcode: Coronal cavities are common features of the solar corona that appear as darkened regions at the base of coronal helmet streamers in coronagraph images. Their darkened appearance indicates that they are regions of lowered density embedded within the comparatively higher density helmet streamer. Despite interfering projection effects of the surrounding helmet streamer (which we refer to as the cavity rim), Fuller et al. have shown that under certain conditions it is possible to use a Van de Hulst inversion of white-light polarized brightness (pB) data to calculate the electron density of both the cavity and cavity rim plasma. In this article, we apply minor modifications to the methods of Fuller et al. in order to improve the accuracy and versatility of the inversion process, and use the new methods to calculate density profiles for both the cavity and cavity rim in 24 cavity systems. We also examine trends in cavity morphology and how departures from the model geometry affect our density calculations. The density calculations reveal that in all 24 cases the cavity plasma has a flatter density profile than the plasma of the cavity rim, meaning that the cavity has a larger density depletion at low altitudes than it does at high altitudes. We find that the mean cavity density is over four times greater than that of a coronal hole at an altitude of 1.2 R sun and that every cavity in the sample is over twice as dense as a coronal hole at this altitude. Furthermore, we find that different cavity systems near solar maximum span a greater range in density at 1.2 R sun than do cavity systems near solar minimum, with a slight trend toward higher densities for systems nearer to solar maximum. Finally, we found no significant correlation of cavity density properties with cavity height—indeed, cavities show remarkably similar density depletions—except for the two smallest cavities that show significantly greater depletion. Title: Flows and Plasma Properties in Quiescent Cavities Authors: Schmit, Donald; Gibson, Sarah Bibcode: 2009shin.confE.116S Altcode: Regions of rarefied density often form cavities above quiescent prominences. In an attempt to constrain the plasma properties of Title: Large-Scale Flows in Prominence Cavities Authors: Schmit, D. J.; Gibson, S. E.; Tomczyk, S.; Reeves, K. K.; Sterling, Alphonse C.; Brooks, D. H.; Williams, D. R.; Tripathi, D. Bibcode: 2009ApJ...700L..96S Altcode: Regions of rarefied density often form cavities above quiescent prominences. We observed two different cavities with the Coronal Multichannel Polarimeter on 2005 April 21 and with Hinode/EIS on 2008 November 8. Inside both of these cavities, we find coherent velocity structures based on spectral Doppler shifts. These flows have speeds of 5-10 km s-1, occur over length scales of tens of megameters, and persist for at least 1 hr. Flows in cavities are an example of the nonstatic nature of quiescent structures in the solar atmosphere. Title: A novel metric for coronal MHD models Authors: Schmit, D. J.; Gibson, S.; de Toma, G.; Wiltberger, M.; Hughes, W. J.; Spence, H.; Riley, P.; Linker, J. A.; Mikic, Z. Bibcode: 2009JGRA..114.6101S Altcode: 2009JGRA..11406101S In the interest of quantitatively assessing the capabilities of coronal MHD models, we have developed a metric that compares the structures of the white light corona observed with SOHO LASCO C2 to model predictions. The MAS model is compared to C2 observations from two Carrington rotations during solar cycle 23, CR1913 and CR1984, which were near the minimum and maximum of solar activity, respectively, for three radial heights, 2.5 R $\odot$ , 3.0 R $\odot$ , and 4.5 R $\odot$ . In addition to simulated polarization brightness images, we create a synthetic image based on the field topology along the line of sight in the model. This open-closed brightness is also compared to LASCO C2 after renormalization. In general, the model's magnetic structure is a closer match to observed coronal structures than the model's density structure. This is expected from the simplified energy equations used in current global corona MHD models. Title: Density and Morphology of Coronal Prominence Cavities Authors: Gibson, Sarah; Fuller, J. Bibcode: 2009SPD....40.2604G Altcode: Coronal prominence cavities are fundamental parts of prominences. They hold clues to the magnetic structure of pre-CME equilibria, and better represent the coronal source of the expanding volume in CMEs and magnetic clouds than a prominence does alone. However, prominence cavities have not been nearly as comprehensively observed and studied as prominences. This is in part due to projection effects which can complicate interpretation of observations, and in part because spectroscopic diagnostic studies require targeted observations, which have only recently been attempted. I will present recent work using white-light observations of cavities to model the morphological and density properties of polar crown filament cavities, with projection effects taken into account. I will also comment on recent attempts to obtain spectral diagnostics of coronal prominence cavities, and will discuss the implications of all of these observations for cavity stability and thermal and magnetic properties. Title: Flows and Plasma Properties in Quiescent Cavities Authors: Schmit, Donald; Gibson, S.; Reeves, K.; Sterling, A.; Tomczyk, S. Bibcode: 2009SPD....40.1015S Altcode: Regions of rarefied density often form cavities above quiescent prominences. In an attempt to constrain the plasma properties of "equilibrium" cavities we conduct several diagnostics using Hinode/EIS, STEREO/EUVI, and CoMP. One novel observation is of large scale flows in cavities. Using different instruments to observe two distinct cavities off the solar limb in coronal emission lines, we find that spectral doppler shifts imply LOS velocities within cavities on the order of 1-10 km/s. These flows occur over length scales of several hundred Mm and persist for hours. Title: Partially-erupting prominences: a comparison between observations and model-predicted observables Authors: Tripathi, D.; Gibson, S. E.; Qiu, J.; Fletcher, L.; Liu, R.; Gilbert, H.; Mason, H. E. Bibcode: 2009A&A...498..295T Altcode: 2009arXiv0902.1228T Aims: We investigate several partially-erupting prominences to study their relationship with other CME-associated phenomena and compare these observations with observables predicted by a model of partially-expelled-flux-ropes (Gibson & Fan 2006a, ApJ, 637, L65; 2006b, J. Geophys. Res., 111, 12103).
Methods: We studied 6 selected events with partially-erupting prominences using multi-wavelength observations recorded by the Extreme-ultraviolet Imaging Telescope (EIT), Transition Region and Coronal Explorer (TRACE), Mauna Loa Solar Observatory (MLSO), Big Bear Solar Observatory (BBSO), and Soft X-ray Telescope (SXT). The observational features associated with partially-erupting prominences were then compared with the predicted observables from the model.
Results: The partially-expelled-flux-rope (PEFR) model can explain the partial eruption of these prominences, and in addition predicts a variety of other CME-related observables that provide evidence of internal reconnection during eruption. We find that all of the partially-erupting prominences studied in this paper exhibit indirect evidence of internal reconnection. Moreover, all cases showed evidence of at least one observable unique to the PEFR model, e.g., dimmings external to the source region and/or a soft X-ray cusp overlying a reformed sigmoid.
Conclusions: The PEFR model provides a plausible mechanism to explain the observed evolution of partially-erupting-prominence-associated CMEs in our study. Title: How do galaxies accrete gas and form stars? Authors: Putman, M. E.; Henning, P.; Bolatto, A.; Keres, D.; Pisano, D. J.; Rosenberg, J.; Bigiel, F.; Bryan, G.; Calzetti, D.; Carilli, C.; Charlton, J.; Chen, H. -W.; Darling, J.; Gibson, S.; Gnedin, N.; Gnedin, O.; Heitsch, F.; Hunter, D.; Kannappan, S.; Krumholz, M.; Lazarian, A.; Lasio, J.; Leroy, A.; Lockman, F. J.; Mac Low, M.; Maller, A.; Meurer, G.; O'Neil, K.; Ostriker, J.; Peek, J. E. G.; Prochaska, J. X.; Rand, R.; Robertson, B.; Schiminovich, D.; Simon, J.; Stanimirovic, S.; Thilker, D.; Thom, C.; Tinker, J.; Wakker, B.; Weiner, B.; van der Hulst, J. M.; Wolfe, A.; Wong, O. I.; Young, L. Bibcode: 2009astro2010S.241P Altcode: 2009arXiv0902.4717P Great strides have been made in the last two decades in determining how galaxies evolve from their initial dark matter seeds to the complex structures we observe at z=0. The role of mergers has been documented through both observations and simulations, numerous satellites that may represent these initial dark matter seeds have been discovered in the Local Group, high redshift galaxies have been revealed with monstrous star formation rates, and the gaseous cosmic web has been mapped through absorption line experiments. Despite these efforts, the dark matter simulations that include baryons are still unable to accurately reproduce galaxies. One of the major problems is our incomplete understanding of how a galaxy accretes its baryons and subsequently forms stars. Galaxy formation simulations have been unable to accurately represent the required gas physics on cosmological timescales, and observations have only just begun to detect the star formation fuel over a range of redshifts and environments. How galaxies obtain gas and subsequently form stars is a major unsolved, yet tractable problem in contemporary extragalactic astrophysics. In this paper we outline how progress can be made in this area in the next decade. Title: Causes of Solar Activity Authors: Giampapa, Mark S.; Gibson, Sarah; Harvey, J. W.; Hill, Frank; Norton, Aimee A.; Pevtsov, A. Bibcode: 2009astro2010S..92G Altcode: No abstract at ADS Title: Magnetically driven activity in the solar corona: a path to understanding the energetics of astrophysical plasmas Authors: Gibson, Sarah; Bastian, Tim; Lin, Haoscheng; Low, B. C.; Tomczyk Bibcode: 2009astro2010S..94G Altcode: No abstract at ADS Title: The Whole Heliosphere Interval: Campaign Summaries and Early Results Authors: Thompson, B.; Gibson, S. E.; McIntosh, S.; Fuller-Rowell, T.; Galvin, A. B.; Kozyra, J. U.; Petrie, G.; Schroeder, P.; Strachan, L.; Webb, D. F.; Woods, T. Bibcode: 2008AGUFMSH21C..01T Altcode: The Whole Heliosphere Interval (WHI) is an internationally coordinated observing and modeling effort to characterize the 3-dimensional interconnected solar-heliospheric-planetary system - a.k.a. the "heliophysical" system. The heart of the WHI campaign is the study of the interconnected 3-D heliophysical domain, from the interior of the Sun, to the Earth, outer planets, and into interstellar space. WHI observing campaigns began with the 3-D solar structure from solar Carrington Rotation 2068, which ran from March 20 - April 16, 2008. Observations and models of the outer heliosphere and planetary impacts extend beyond those dates as necessary; for example, the solar wind transit time to outer planets can take months. WHI occurred during solar minimum, which optimizes our ability to characterize the 3-D heliosphere and trace the structure to the outer limits of the heliosphere. Highlights include the 3-D reconstruction of the solar wind and complex geospace response during this solar minimum, contrasts with the past solar minimum, and the effect of transient activity on the "quiet" heliosphere. Nearly 200 scientists are participated in WHI data and modeling efforts, ensuring that the WHI integrated observations and models will give us a "new view" of the heliophysical system. A summary of some of the key results from the WHI first workshop in August 2008 will be given. Title: Constructing a Data System to Support Analysis of the Whole Heliosphere Interval Authors: Thompson, B. J.; Schroeder, P. C.; Gibson, S. E. Bibcode: 2008AGUFMSH23A1632T Altcode: The Whole Heliosphere Interval is an internationally coordinated observing and modeling effort to characterize the 3-dimensional interconnected solar-heliospheric-planetary system. The WHI observing campaigns began with the 3-D solar structure from solar Carrington Rotation 2068, which ran from March 20 to April 16, 2008, and traced these structures through the heliosphere and into geospace. The WHI team has developed a data and modeling clearinghouse to create a unified point of entry into the disparate data sets spanning across the traditional disciplinary boundaries. Linkages are provided to data from the special observing programs conducted by many observatories for the WHI effort, models that looked in detail at the WHI and the many other data sets and models from the interval. We also explore the Virtual Observatory landscape and highlight their contributions to the development of a more complete understanding of the entire heliophysical system. Title: Partially ejected flux ropes: Implications for interplanetary coronal mass ejections Authors: Gibson, S. E.; Fan, Y. Bibcode: 2008JGRA..113.9103G Altcode: Connecting interplanetary coronal mass ejections (ICMEs) to their solar pre-eruption source requires a clear understanding of how that source may have evolved during eruption. Gibson and Fan (2006a) have presented a three-dimensional numerical magnetohydrodynamic simulation of a CME, which showed how, in the course of eruption, a coronal flux rope may writhe and reconnect both internally and with surrounding fields in a manner that leads to a partial ejection of only part of the rope as a CME. In this paper, we will explicitly describe how the evolution during eruption found in that simulation leads to alterations of the magnetic connectivity, helicity, orientation, and topology of the ejected portion of the rope so that it differs significantly from that of the pre-eruption rope. Moreover, because a significant part of the magnetic helicity remains behind in the lower portion of the rope that survives the eruption, the region is likely to experience further eruptions. These changes would complicate how ICMEs embedded in the solar wind relate to their solar source. In particular, the location and evolution of transient coronal holes, topology of magnetic clouds ("tethered spheromak"), and likelihood of interacting ICMEs would differ significantly from what would be predicted for a CME which did not undergo writhing and partial ejection during eruption. Title: Whole Heliosphere Interval: Overview of Heliospheric Observations Authors: Galvin, A. B.; Gibson, S.; Heliosphere Team Bibcode: 2008AGUSMSH53A..07G Altcode: The Whole Heliosphere Interval (http://ihy2007.org/WHI/) is an international observing and coordinated modeling effort to characterize the interconnections of the 3-dimensional sun-heliosphere-planetary system originating from Carrington Rotation 2068. WHI takes place one solar cycle after the "Whole Sun Month" campaign of 1996. Both WSM and WHI covered the sun and heliosphere near solar minimum conditions, providing a basis for comparison from one solar cycle to the next. The primary goals for WHI include the characterization and modeling in 3D of the solar minimum heliosphere, and to trace the affects of solar structure and activity via the solar wind to Earth, other planetary systems, and the outer heliosphere. Team participants address solar, heliospheric, geospace, planetary systems, space weather, and sun-climate observations and models. In this talk, we provide a "first results" summary of the heliospheric observations portion of WHI. At this writing, the heliospheric observations are expected to include modeling as well as measurements from L1 (ACE, SOHO, Wind), other solar longitudes near 1 AU (STEREO A, STEREO B), remote sensing from Earth or near-Earth (Ooty Radio Observatory, SMEI, EISCAT), out-of-the ecliptic (Ulysses), and from the outer heliosphere (Voyager, IBEX). For Voyager and IBEX, the observing interval extends until the affects originating from CR 2068 reach the outer heliosphere, several months later. Title: Forming tori: Implications and possible origins of a "tethered spheromak" topology for magnetic clouds Authors: Gibson, S. E.; Fan, Y. Bibcode: 2008AGUSMSH31C..06G Altcode: We present a "tethered spheromak" model for magnetic clouds. The proposed topology differs from previous magnetic cloud models invoking spheromaks in that large portions of the field remain connected to the sun. This magnetic configuration may explain observed departures from the standard magnetic cloud model of a cylindrically-symmetric magnetic flux rope, such as magnetic fields which rotate more than 180 degrees. It is also topologically complex enough to include intermingled detached, doubly attached, and apparently open fields in a manner consistent with observations of sporadic heat flux dropouts within otherwise bidirectional or unidirectional streaming electrons. We use a numerical simulation to demonstrate how, for solar eruptions where the kink instability drives significant rotation of an erupting flux rope, such a tethered spheromak may form during that rope's partial ejection. It does so because writhing motions and reconnections create twist about two distinct axes of rotation: the first associated with the rotated portion of the original rope axis, and the second formed in situ via reconnections between the erupting rope and surrounding coronal arcade fields. Title: Whole Heliosphere Interval: Introduction Authors: Gibson, S. E.; Thompson, B. J.; Webb, D. Bibcode: 2008AGUSMSH53A..01G Altcode: The Whole Heliosphere Interval (WHI) is an international coordinated observing and modeling effort to characterize the three-dimensional interconnected solar-heliospheric-planetary system at solar minimum, using observations originating at the Sun during Carrington Rotation 2067: March 20 - April 16, 2008. WHI's science begins with the solar interior and extends through the heliosphere and interplanetary space out to the heliopause. WHI is a special campaign period of the International Heliophysical Year, and involves the participation of many observatories and researchers around the world. A "synoptic" set of observations provides baseline measurements of the heliophysical system, while "targeted" observing campaigns during the WHI interval focuses on particular sub-regions of the coupled heliospheric system and address specific scientific questions via day-to-day coordinated observations. This introductory talk will begin this special session dedicated to providing a broad description of the heliosphere at solar minimum by showcasing early results of the WHI campaign. Title: Observing the unobservable? Modeling coronal cavity densities Authors: Fuller, J.; Gibson, S. E.; Detoma, G.; Fan, Y. Bibcode: 2008AGUSMSP51A..04F Altcode: Prominence cavities in coronal helmet streamers are readily detectable in white light coronagraph images, yet their interpretation may be complicated by projection effects. In order to determine a cavity's density structure, it is essential to quantify the contribution of non-cavity features along the line of sight. We model the coronal cavity as an axisymmetric torus that encircles the Sun at constant latitude, and fit it to observations of a white light cavity observed by the Mauna Loa Solar Observatory (MLSO) MK4 coronagraph from January 25-30, 2006. We demonstrate that spurious non-cavity contributions (including departures from axisymmetry) are minimal enough to be incorporated in a density analysis as conservatively estimated uncertainties in the data. We calculate a radial density profile for cavity material and for the surrounding helmet streamer (which we refer to as the "cavity rim"), and find that the cavity density is depleted by a maximum of 40 percent compared to the surrounding helmet streamer at low altitudes (1.18 solar radii), but is consistently higher (double or more) than in coronal holes. We also find that the relative density depletion between cavity and surrounding helmet decreases as a function of height. We show that both increased temperature in the cavity relative to the surrounding helmet streamer and a magnetic flux rope configuration might lead to such a flattened density profile. Finally, our model provides general observational guidelines that can be used to determine when a cavity is sufficiently unobstructed to be a good candidate for plasma diagnostics. Title: Observing the Unobservable? Modeling Coronal Cavity Densities Authors: Fuller, J.; Gibson, S. E.; de Toma, G.; Fan, Y. Bibcode: 2008ApJ...678..515F Altcode: Prominence cavities in coronal helmet streamers are readily detectable in white-light coronagraph images, yet their interpretation may be complicated by projection effects. In order to determine a cavity's density structure, it is essential to quantify the contribution of noncavity features along the line of sight. We model the coronal cavity as an axisymmetric torus that encircles the Sun at constant latitude and fit it to observations of a white-light cavity observed by the Mauna Loa Solar Observatory (MLSO) MK4 coronagraph from 2006 January 25 to 30. We demonstrate that spurious noncavity contributions (including departures from axisymmetry) are minimal enough to be incorporated in a density analysis as conservatively estimated uncertainties in the data. We calculate a radial density profile for cavity material and for the surrounding helmet streamer (which we refer to as the "cavity rim") and find that the cavity density is depleted by a maximum of 40% compared to the surrounding helmet streamer at low altitudes (1.18 R⊙) but is consistently higher (double or more) than in coronal holes. We also find that the relative density depletion between cavity and surrounding helmet decreases as a function of height. We show that both increased temperature in the cavity relative to the surrounding helmet streamer and a magnetic flux rope configuration might lead to such a flattened density profile. Finally, our model provides general observational guidelines that can be used to determine when a cavity is sufficiently unobstructed to be a good candidate for plasma diagnostics. Title: Geospace, Heliospheric and Solar Data collected during the Whole Heliosphere Interval Authors: Thompson, B. J.; Gibson, S. E.; Webb, D. F. Bibcode: 2008AGUSMSH51A..01T Altcode: The Whole Heliosphere Interval is a comprehensive observing and modeling campaign that seeks to connect variations in the Earth's ionosphere and magnetosphere with structure and energy variations in the heliosphere and solar corona. Hundreds of researchers from around the world participated by performing observations and contributing data from an extensive array of sources. This poster will summarize the observations taking during WHI, including special observations performed under the targeted observing campaigns. Title: Multi-wavelength Comparison of Prominence Cavities Authors: Schmit, D. J.; Gibson, S.; de Toma, G.; Reeves, K.; Tripathi, D.; Kucera, T.; Marque, C.; Tomczyk, S. Bibcode: 2008AGUSMSP43B..04S Altcode: Recent observational campaigns have brought together a wealth of data specifically designed to explore the physical properties and dynamics of prominence cavities. In particular, STEREO and Hinode data have provided new perspectives on these structures. In order to effectively analyze the data in a cohesive manner, we produce overlays of several distinct and complimentary datasets including SOHO UVCS, CDS, and EIT, Hinode SOT and EIS, STEREO SECCHI, TRACE, and Nancay Radioheliograph data as well as new observations of coronal magnetic fields in cavities from the Coronal Multichannel Polarimeter. We are thus able to investigate how sensitive morphology is to the wavelength observed which details the nature of the plasma in the cavity. Title: Whole Heliosphere Interval: Early Science Results Authors: Gibson, Sarah; Webb, David; Thompson, Barbara Bibcode: 2008cosp...37.1011G Altcode: 2008cosp.meet.1011G The Whole Heliosphere Interval (WHI) is an international coordinated observing and modeling effort to characterize the three-dimensional interconnected solar-heliospheric-planetary system at solar minimum, using observations originating at the Sun during Carrington Rotation 2067: March 20 - April 16, 2008. WHI's science begins with the solar interior and extends through the heliosphere and interplanetary space out to the heliopause. WHI is a special campaign period of the International Heliophysical Year, and involves the participation of many observatories and researchers around the world. A "synoptic" set of observations provides baseline measurements of the heliophysical system, while "targeted" observing campaigns during the WHI interval focuses on particular sub-regions of the coupled heliospheric system and address specific scientific questions via day-to-day coordinated observations. This talk will showcase early results of the WHI campaign, and thus provide a broad description of the heliosphere at solar minimum. Title: Whole Heliosphere Interval: Origins and characteristics of the quiet solar wind Authors: Gibson, Sarah Bibcode: 2008cosp...37.1010G Altcode: 2008cosp.meet.1010G The Whole Heliosphere Interval (WHI) is an international coordinated observing and modeling effort to characterize the three-dimensional interconnected solar-heliospheric-planetary system during solar minimum, using data originating at the Sun during Carrington Rotation 2067: March 20 - April 16, 2008. WHI is a special campaign period of the International Heliophysical Year, and involves the participation of many participating observatories and researchers around the world. WHI's science begins with the solar interior and extends through the heliosphere and interplanetary space out to the heliopause. I will focus on the origins and characteristics of the quiet solar wind, and summarize the early results of the WHI campaign in order to provide a broad description of the heliosphere at solar minimum. Title: Hidden Galactic Accretion: The Discovery of Low-Velocity Halo Clouds Authors: Peek, J. E. G.; Putman, M. E.; Sommer-Larsen, J.; Heiles, C. E.; Stanimirovic, S.; Douglas, K.; Gibson, S.; Korpela, E. Bibcode: 2007AAS...211.1408P Altcode: 2007BAAS...39..760P High-Velocity Clouds (HVCs) have been thought to be part of the Galactic accretion process since their discovery more than 40 years ago. Two modes through which HVCs may be generated and contribute to the ongoing growth of our Galaxy are (1) the tidal stripping of satellite galaxies and (2) the fragmented condensation of the Galaxy's hot baryonic halo. We have run cosmological Tree-SPH simulations of a Milky-Way sized galaxy, in which we can resolve clouds down to 10^5 M⊙, in an attempt to probe the cooling halo accretion process. The simulations show that this HVC generation mechanism can indeed reproduce the characteristics of observed population of HVCs, including the flux, velocity and cloud clustering properties. These simulations also predict an equally large population of halo clouds moving at lower radial velocities: Low-Velocity Halo Clouds (LVHCs). These clouds would not be observed as HVCs, but would rather be confused with local disk gas. Taking advantage of the known empirical result that HVCs have undetectably low infrared dust flux compared to their 21cm column, we search for these clouds in the preliminary GALFA-HI survey and IRAS. We announce the discovery of the first examples of these clouds, and describe their properties. This work was supported in part by NSF grant AST 04-06987 and NSF grant AST 07-09347. Title: Onset of coronal mass ejections due to loss of confinement of coronal flux ropes Authors: Fan, Y.; Gibson, S. Bibcode: 2007AGUFMSH51C..04F Altcode: Using MHD numerical simulations in a three-dimensional spherical geometry, we model the loss of confinement and eruption of a flux rope emerging quasistatically into a pre-existing coronal arcade field. Our numerical experiments have investigated two distinct triggering mechanisms that led to the eruption of the flux rope. In one case, the overlying arcade field declines with height more slowly such that the emerging flux rope remains confined until a high amount of internal twist is built up, with the rope self-helicity normalized by the square of the rope flux reaching about -1.4, and the flux rope becomes significantly kinked. The kinking motion causes rotation of the tube to an orientation that makes it easier for it to rupture through the arcade field, leading to an eruption. In the second case, the overlying field is made to decline more rapidly with height and the emerging flux rope is found to lose equilibrium and erupt via the torus instability when the flux rope self-helicity normalized by the square of the rope flux is only -0.63, before it becomes kinked. The values of the total relative magnetic helicity normalized by the square of the total anchored flux are, on the other hand, quite close for the two cases when the eruption takes place. We study the eruptive properties resulting from the two mechansisms and compare them with observations. Title: Source of Nitrogen Isotope Anomaly in HCN in the Atmosphere of Titan Authors: Liang, Mao-Chang; Heays, A.; Lewis, B.; Gibson, S.; Yung, Y. Bibcode: 2007DPS....39.4705L Altcode: 2007BAAS...39R.505L The14N/15N ratio for N2 in the atmosphere of Titan was recently measured to be a factor of two higher than the corresponding ratio for HCN. Using a one-dimensional photochemical model with transport, we incorporate new isotopic photoabsorption and photodissociation cross sections of N2, computed quantum-mechanically, and show that the difference in the ratio of 14N/15N between N2 and HCN can be explained primarily by the photolytic fractionation of 14N14N and 14N15N. The [HC14N]/[HC15N] ratio produced by N2 photolysis alone is 23. This value, together with the observed ratio, constrain the flux of atomic nitrogen input from the top of the atmosphere to be in the range 1-2×109 atoms cm-2 s-1.

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There remains a major challenge to explain the low 14N/15N ratio for N2 in the atmosphere of Titan. In view of our success in explaining the isotopic composition of HCN, we believe that the resolution of the nitrogen isotopic fraction lies in (1) the photochemistry of NH3, (2) the isotopic fractionation of 15N in NH3 photolysis, and (3) hydrodynamic escape. It is conceivable that some of the nitrogen in the primitive Titan might have been sequestered as HCN subduction to the interior of Titan, followed by conversion back to N2 which would contribute to the isotopic enrichment of 15N in the N2 atmosphere. Title: Onset of Coronal Mass Ejections Due to Loss of Confinement of Coronal Flux Ropes Authors: Fan, Y.; Gibson, S. E. Bibcode: 2007ApJ...668.1232F Altcode: Using MHD numerical simulations in a three-dimensional spherical geometry, we model the loss of confinement and eruption of a flux rope emerging quasi-statically into a preexisting coronal arcade field. Our numerical experiments investigated two distinct mechanisms that led to the eruption of the flux rope. In one case, the overlying arcade field declines with height slowly such that the emerging flux rope remains confined until its self-relative magnetic helicity normalized by the square of the rope's flux reaches -1.4 and the flux rope becomes significantly kinked. The kinking motion causes rotation of the tube to an orientation that makes it easier for it to rupture through the arcade field, leading to an eruption. In the second case, the overlying field declines more rapidly with height, and the emerging flux rope is found to lose equilibrium and erupt via the torus instability when its self-relative magnetic helicity normalized by the square of its flux is only approximately -0.63, before it becomes kinked. The values of the total relative magnetic helicity of the entire coronal magnetic field (including both the flux rope and the arcade field) normalized by the square of the total magnetic flux are, on the other hand, of similar magnitudes for the two cases when the eruption takes place. We compare and contrast the eruptive properties and the posteruption states resulting from the two cases. Title: Coronal Mass Ejections Due to Loss of Confinement of Coronal Flux Ropes Authors: Fan, Yuhong; Gibson, S. Bibcode: 2007AAS...210.2919F Altcode: 2007BAAS...39..140F Using MHD numerical simulations in a three-dimensional spherical geometry, we model the loss of confinement and eruption of a flux rope emerging quasistatically into a pre-existing coronal arcade field. Our numerical experiments have investigated two distinct cases that led to the eruption of the flux rope. In one case, the overlying arcade field declines with height more slowly such that the emerging flux rope remains confined until a high amount of twist is built up, with the rope self-helicity normalized by the square of the rope flux reaching about -1.4, and the flux rope becomes significantly kinked. The kinking motion causes rotation of the tube to an orientation that makes it easier for it to rupture through the arcade field, leading to an eruption. In the second case, the overlying field is made to decline more rapidly with height and the emerging flux rope is found to lose equilibrium and erupt via the torus instability when the flux rope self-helicity normalized by the square of the rope flux is only -0.6, and before it becomes kinked. The values of the total relative magnetic helicity normalized by the square of the total magnetic flux are, on the other hand, quite close for the two cases when eruption takes place. We compare and contrast the eruptive properties and the post-eruption states of the two cases, and discuss their observational consequences. Title: Splitting Flux Ropes: Modeling The Eruption Of Magnetic Structures On The Sun Authors: Gibson, Sarah; Fan, Y. Bibcode: 2007AAS...210.5806G Altcode: 2007BAAS...39..168G Coronal mass ejections (CMEs) and their associated space weather manifestations are routinely interpreted as possessing a helical magnetic flux rope structure. An ongoing controversy remains, however, as to whether a precursor flux rope exists as a coronal equilibrium state prior to eruption, or whether it is formed during eruption. This is an important question to resolve, since CME initiation models and space weather predictions depend upon a clear understanding of the configuration of pre-CME magnetic fields and their evolution during eruption. We will describe an alternative which lies between the two extremes of a totally erupting, pre-existing rope, and a rope that forms completely in situ during eruption, i.e., a precursor flux rope that splits in two and reconnects with surrounding fields during eruption. We consider the implications of such a "partially-expelled flux rope" model for a range of CME-related observations, including partially-erupting filaments, the evolution of post-flare loops and flare ribbon morphologies, and transient coronal holes. Title: Food Mobilities Authors: Gibson, Sarah Bibcode: 2007SpCul..10....4G Altcode: This article explores how food is good to think mobilities with. Food, taste, and eating are all implicated in differing mobilities, whether corporeal, technological, imaginative, or virtual. The space of the dining car brings together the corporeal mobility of passengers, the technological mobility of the railways, and the mobility of food. Through the reflections of eating in the dining car by E. M. Forster and Roland Barthes, this article explores this particular experience of eating on the move, before examining how cultures of food and eating are central to experiences of "traveling-indwelling" and "dwelling-in-traveling" through the wider connections of food mobilities. Title: The Evolving Sigmoid: Evidence for Magnetic Flux Ropes in the Corona Before, During, and after CMES Authors: Gibson, S. E.; Fan, Y.; Török, T.; Kliem, B. Bibcode: 2007sdeh.book..131G Altcode: No abstract at ADS Title: Coronal prominence structure and dynamics: A magnetic flux rope interpretation Authors: Gibson, S. E.; Fan, Y. Bibcode: 2006JGRA..11112103G Altcode: The solar prominence is an example of a space physics phenomenon that can be modeled as a twisted magnetic flux tube or magnetic flux "rope." In such models the prominence is one observable part of a larger magnetic structure capable of storing magnetic energy to drive eruptions. We show how a flux rope model explains a range of observations of prominences and associated structures such as cavities and soft X-ray sigmoids and discuss in particular the observational and dynamic consequences of three-dimensional reconnections in and around the evolving magnetic flux rope. We demonstrate that the flux rope model can describe the prominence's preeruption structure and dynamics, loss of equilibrium, and behavior during and after an eruption in which part of the flux rope is expelled from the corona. Title: The Evolving Sigmoid: Evidence for Magnetic Flux Ropes in the Corona Before, During, and After CMES Authors: Gibson, S. E.; Fan, Y.; Török, T.; Kliem, B. Bibcode: 2006SSRv..124..131G Altcode: 2007SSRv..tmp...52G It is generally accepted that the energy that drives coronal mass ejections (CMEs) is magnetic in origin. Sheared and twisted coronal fields can store free magnetic energy which ultimately is released in the CME. We explore the possibility of the specific magnetic configuration of a magnetic flux rope of field lines that twist about an axial field line. The flux rope model predicts coronal observables, including heating along forward or inverse S-shaped, or sigmoid, topological surfaces. Therefore, studying the observed evolution of such sigmoids prior to, during, and after the CME gives us crucial insight into the physics of coronal storage and release of magnetic energy. In particular, we consider (1) soft-X-ray sigmoids, both transient and persistent; (2) The formation of a current sheet and cusp-shaped post-flare loops below the CME; (3) Reappearance of sigmoids after CMEs; (4) Partially erupting filaments; (5) Magnetic cloud observations of filament material. Title: Is Reconnection Necessary for Kinked CME Onset? Authors: Rachmeler, Laurel; DeForest, C. E.; Gibson, S. E.; Fan, Y. Bibcode: 2006SPD....37.0902R Altcode: 2006BAAS...38..236R We present initial results from a controlled numerical experiment to determine whether CME onset requires reconnection or can be driven primarily by loss of plasma equilibrium. The early onset of the kink instability proceeds with little reconnection in traditional MHD simulations, but still at a nonzero rate. After the initial onset of the instability, reconnection proceeds rapidly across the newly formed current sheet, contributing to the ejection of the kink. We have simulated the kink instability driven purely by loss of plasma equilibrium - in the absence of numerical reconnection - as an early step to understanding the role of reconnection in CME evolution. Title: Validation Techniques for the MAS Corona Model Authors: Schmit, D.; Gibson, S.; Detoma, G.; Wiltberger, M. Bibcode: 2006AGUSMSH43A..01S Altcode: In the interest of making competent predictions about the structure of the solar corona, we have developed the tools necessary to quantitatively compare the Magnetohydrodynamics Around a Sphere (MAS) numerical model to the observed corona. The SAIC coronal modeling group has written an algorithm that creates a two dimensional polarization brightness image of the corona from the model density output by computing the line of sight integral for scattered white light. Using the tools we developed for the CISM Data Explorer, the white light intensity is extracted from the image around the full disk of the Sun at a given radial height. A series of these images, spanning a Carrington rotation, are processed through this method into a Carrington Map, which we use for direct comparison against LASCO C2 polarization brightness data. Our validation will begin with a chi-squared comparison of model to observations of the latitude of the streamer belt brightness maximum during the Whole Sun Month. Title: On the Nature of the X-Ray Bright Core in a Stable Filament Channel Authors: Fan, Y.; Gibson, S. E. Bibcode: 2006ApJ...641L.149F Altcode: In a search for the cause of the intense heating revealed by X-ray emission in filament channels, we have simulated the evolution of a twisted toroidal flux rope emerging quasi-statically into the corona. Initially, the simulated flux rope remains confined in equilibrium as the stored magnetic energy increases. With enough twist buildup, there is a sudden catastrophic loss of equilibrium and total expulsion of the flux rope. We focused on the quasi-static phase in which a current sheet forms within the flux rope cavity, along the so-called bald-patch separatrix surface (BPSS). This comprises an envelope of field lines that graze the anchoring lower boundary, enclosing the detached helical field that supports the prominence. Significant magnetic energy dissipation and heating are expected to center around such current sheets. The heating that should result provides a plausible explanation for the hot X-ray sources, although they appear to be colocated with cool material. If our physical picture is correct, then the development of X-ray ``bright cores'' or ``sigmoids'' in a filament channel suggests the presence of a BPSS separating the helical field of a twisted flux rope in stable confinement from the surrounding untwisted fields. Title: The Calm before the Storm: The Link between Quiescent Cavities and Coronal Mass Ejections Authors: Gibson, S. E.; Foster, D.; Burkepile, J.; de Toma, G.; Stanger, A. Bibcode: 2006ApJ...641..590G Altcode: Determining the state of the corona prior to CMEs is crucial to understanding and ultimately predicting solar eruptions. A common and compelling feature of CMEs is their three-part morphology, as seen in white-light observations of a bright expanding loop, followed by a relatively dark cavity, and finally a bright core associated with an erupting prominence/filament. This morphology is an important constraint on CME models. It is also quite common for a three-part structure of loop, cavity, and prominence core to exist quiescently in the corona, and this is equivalently an important constraint on models of CME-precursor magnetic structure. These quiescent structures exist in the low corona, primarily below approximately 1.6 Rsolar, and so are currently observable in white light during solar eclipses, or else by the Mauna Loa Solar Observatory Mk4 coronameter. We present the first comprehensive, quantitative analysis of white-light quiescent cavities as observed by the Mk4 coronameter. We find that such cavities are ubiquitous, as they are the coronal limb counterparts to filament channels observed on the solar disk. We consider examples that range from extremely long-lived, longitudinally extended polar-crown-filament-related cavities to smaller cavities associated with filaments near or within active regions. The former are often visible for days and even weeks at a time and can be identified as long-lived cavities that survive for months. We quantify cavity morphology and intensity contrast properties and consider correlations between these properties. We find multiple cases in which quiescent cavities directly erupt into CMEs and consider how morphological and intensity contrast properties of these cases differ from the general population of cavities. Finally, we discuss the implications that these observations may have for the state of the corona just prior to a CME, and more generally for the nature of coronal MHD equilibria. Title: The Partial Expulsion of a Magnetic Flux Rope Authors: Gibson, S. E.; Fan, Y. Bibcode: 2006ApJ...637L..65G Altcode: We demonstrate the partial expulsion of a three-dimensional magnetic flux rope, in which an upper, escaping rope is separated from a lower, surviving rope by cusped, reconnecting loop field lines. We use the three-dimensional magnetohydrodynamic model recently presented by Fan, extended to examine the erupting rope's end state. As in that work, the modeled flux rope in spherical coordinates erupts when enough twist has emerged to induce a loss of equilibrium. After multiple reconnections at current sheets that form during the eruption, the rope breaks in two, so that only a part of it escapes. We consider the details of how this separation occurs and discuss the observational significance of such a partially expelled flux rope for partially erupting filaments and re-forming X-ray sigmoids. Title: The emergence and evolution of twisted coronal magnetic fields: comparing models and observations Authors: Gibson, S.; Fan, Y. Bibcode: 2006cosp...36.1839G Altcode: 2006cosp.meet.1839G We will present new results comparing coronal plasma observations to observables predicted by MHD models of twisted magnetic structures in the corona We will focus on their emergence through the photosphere their subsequent equilibrium states and their eruptive properties We will show that observations of coronal filaments before during and after eruptions can be explained In particular we will demonstrate that the observed relationship between filament filament cavity and hot X-ray sources such as sigmoids are reproduced for a variety of twisted magnetic structures in equilibrium We will also demonstrate that modeled loss of equilibrium and eruption of such magnetic structures can explain a range of observed behaviors of filaments their cavities and X-ray sigmoids during and after eruptions These include observations of partially-erupting filaments and the immediate reformation of X-ray sigmoids after an eruption Title: Partially-ejected flux ropes: implications for space weather Authors: Gibson, Sarah E.; Fan, Yuhong Bibcode: 2006IAUS..233..319G Altcode: The structure and evolution of the sources of solar activity directly affects the nature of space weather disturbances that reach the Earth. We have previously demonstrated that the loss of equilibrium and partial ejection of a coronal magnetic flux rope matches observations of coronal mass ejections (CMEs) and their precursors.In this paper we discuss the significance of such a partially-ejected rope for space weather. We will consider how the evolution and bifurcation of the rope modifies it from its initial, source configuration. In particular, we will consider how reconnections and writhing motions lead to an escaping rope which has an axis rotated counterclockwise from the original rope axis orientation, and which is rooted in transient coronal holes external to the original source region. Title: The Emergence and Evolution of Twisted Magnetic Flux Ropes in the Solar Corona Authors: Fan, Y.; Gibson, S. E.; Manchester, W. Bibcode: 2005ESASP.596E..26F Altcode: 2005ccmf.confE..26F No abstract at ADS Title: Evolution of Twisted Magnetic Flux Robes Emerging into the Solar Corona (Invited) Authors: Fan, Y.; Gibson, S. E. Bibcode: 2005ESASP.592..241F Altcode: 2005ESASP.592E..36F; 2005soho...16E..36F No abstract at ADS Title: CME Onset Due to Loss of Confinement of Twisted Magnetic Flux Ropes Authors: Fan, Y.; Gibson, S. Bibcode: 2005AGUSMSP23A..08F Altcode: We present MHD simulations in both 2D axisymmetric and 3D spherical geometries of the evolution of a twisted magnetic flux rope emerging into the low-β corona previously occupied by a potential arcade field. We describe both the initial quasi-static evolution whereby stable equilibrium structures can form with stored free magnetic energy, and the eventual loss of confinement or equilibrium of the twisted magnetic flux rope as sufficient twist is being transported into the corona, resulting in the onset of a CME. We investigate how the evolution and the loss of equilibrium for a 3D line-tied flux rope differ compared to the case of a 2D axisymmetric flux rope. Title: Harvey Prize Lecture: The calm before the storm: the link between quiescent cavities and CMEs Authors: Gibson, S. E. Bibcode: 2005AGUSMSP43C..01G Altcode: Coronal mass ejections (CMEs) are thought to be driven by magnetic energy, stored in twisted or sheared magnetic fields. Magnetic clouds, which are interplanetary manifestations of CMEs, are commonly modeled as flux ropes of twisted magnetic field. It has also become quite standard to model the erupting CME as a flux rope. However, the question of whether the flux rope is formed during the eruption, or whether the flux rope existed prior to the eruption, remains controversial. CMEs often possess a three-part morphology in white light observations of a bright front, followed by a relatively dark cavity, and lastly a bright core associated with an erupting prominence. The three-part structure of CMEs has been shown in a variety of models to be a consequence of a magnetic flux rope topology. The same physical reasons for the presence of the cavity system in eruption hold true in quiescence, and so it is significant that the three-part structure, in the form of helmet-streamer/cavity/prominence-core often exists quiescently in the corona. I will present an analysis of a few case studies of white light quiescent cavities as observed by the HAO Mauna Loa Solar Observatory Mk4 coronagraph. In particular I will consider the 3D structure and evolution of these cavities, and how these are related to CMEs. Finally, I will discuss the implications that these observations may have for the state of the corona just prior to a CME, and more generally for the nature of coronal MHD equilibria. Title: Multialtitude Observations of a Coronal Jet during the Third Whole Sun Month Campaign Authors: Ko, Y. -K.; Raymond, J. C.; Gibson, S. E.; Alexander, D.; Strachan, L.; Holzer, T.; Gilbert, H.; Cyr, O. C. St.; Thompson, B. J.; Pike, C. D.; Mason, H. E.; Burkepile, J.; Thompson, W.; Fletcher, L. Bibcode: 2005ApJ...623..519K Altcode: On 1999 August 26, a coronal jet occurred at the northwest limb near a sigmoid active region (AR 8668) that was the target for a joint observation plan (SOHO joint observing program 106) during the third Whole Sun Month Campaign. This jet was observed by several instruments at the limb (SOHO/CDS, SOHO/EIT, TRACE, and Mauna Loa Solar Observatory CHIP and PICS) and at 1.64 Rsolar (SOHO/UVCS). At the limb, this jet event displayed both low- and high-temperature components. Both high- and low-temperature components were evident during the early phase (first 20 minutes) of the event. However, the low-temperature component is maintained for ~1 hr after the higher temperature component is gone. There is a second brightening (a possible second jet) seen by EIT and TRACE about 50 minutes after the onset of the first jet. The line-of-sight motion at the limb began with a 300 km s-1 redshift and evolved to a 200 km s-1 blueshift. At 1.64 Rsolar, the intensities of Lyα and Lyβ in the jet increased by a factor of several hundred compared with the background corona. The C III λ977 line also brightened significantly. This indicates low-temperature [~(1-2)×105 K] emission in the jet, while the intensities of O VI λ1032 and O VI λ1037 increased by as much as a factor of 8. The UVCS data show evidence of heating at the early phase of the event. The Doppler shift in the lines indicates that the line-of-sight (LOS) velocity in the jet started from ~150 km s-1 in blueshift and ended at ~100 km s-1 in redshift. This LOS motion seen at 1.64 Rsolar was apparently opposite to what was observed when the jet emerged from the limb. The Doppler dimming analysis indicates that the radial outflow speed correlates with the magnitude of the LOS speed. Interestingly, UVCS observations at 2.33 and 2.66 Rsolar show no trace of the jet and SOHO/LASCO observations also yield no firm detection. We find that a simple ballistic model can explain most of the dynamical properties of this jet, while the morphology and the thermal properties agree well with reconnection-driven X-ray jet models. Title: Observational Consequences of a Magnetic Flux Rope Emerging into the Corona Authors: Gibson, S. E.; Fan, Y.; Mandrini, C.; Fisher, G.; Demoulin, P. Bibcode: 2004ApJ...617..600G Altcode: We show that a numerical simulation of a magnetic flux rope emerging into a coronal magnetic field predicts solar structures and dynamics consistent with observations. We first consider the structure, evolution, and relative location and orientation of S-shaped, or sigmoid, active regions and filaments. The basic assumptions are that (1) X-ray sigmoids appear at the regions of the flux rope known as ``bald-patch-associated separatrix surfaces (BPSSs), where, under dynamic forcing, current sheets can form, leading to reconnection and localized heating, and that (2) filaments are regions of enhanced density contained within dips in the magnetic flux rope. We demonstrate that the shapes and relative orientations and locations of the BPSS and dipped field are consistent with observations of X-ray sigmoids and their associated filaments. Moreover, we show that current layers indeed form along the sigmoidal BPSS as the flux rope is driven by the kink instability. Finally, we consider how apparent horizontal motions of magnetic elements at the photosphere caused by the emerging flux rope might be interpreted. In particular, we show that local correlation tracking analysis of a time series of magnetograms for our simulation leads to an underestimate of the amount of magnetic helicity transported into the corona by the flux rope, largely because of undetectable twisting motions along the magnetic flux surfaces. Observations of rotating sunspots may provide better information about such rotational motions, and we show that if we consider the separated flux rope legs as proxies for fully formed sunspots, the amount of rotation that would be observed before the region becomes kink unstable would be in the range 40°-200° per leg/sunspot, consistent with observations. Title: The Role of Garnet Pyroxenite in High-Fe Mantle Melt Generation: High Pressure Melting Experiments Authors: Tuff, J.; Takahashi, E.; Gibson, S. Bibcode: 2004AGUFM.V51B0523T Altcode: Evidence for the existence of heterogeneous or 'marble cake' convecting mantle1 is provided recently by rare, high MgO ( ∼ 15 wt.%) primitive magmas with anomalously high abundances of FeO* ( ∼ 13.5 to 16 wt. %2,3; where FeO* = total Fe as FeO). These high-Fe mantle melts show a limited occurrence in the initial stage of magmatism in large igneous provinces (e.g. Deccan, Ethiopia and Paraná-Etendeka) and some have incompatible trace-element and radiogenic-isotopic ratios (Sr, Nd and Pb) that resemble those of ocean-island basalts. This suggests that they are predominantly derived from the convecting mantle2. The ferropicrites are mildly- to sub-alkaline and have low contents of Al2O3 (< 10 wt.%) and heavy rare-earth elements (e.g. Lu < 0.18ppm) that are consistent with the increased stability of garnet, due to the high FeO* content in the ferropicrite mantle source. It has been proposed that the source of the high FeO* may be garnet-pyroxenite streaks derived from subducted mafic oceanic crust2. We have undertaken melting experiments between 1 atmosphere and 7 GPa in order to determine the anhydrous phase relations of an uncontaminated ferropicrite lava from the base of the Early-Cretaceous Paraná-Etendeka continental flood-basalt province. The sample has high contents of MgO ( ∼ 14.9 wt.%), FeO* (14.9 wt.%) and NiO (0.07 wt.%). Olivine phenocrysts have maximum Fo contents of 85 and are in equilibrium with the host rock, assuming a Kd of 0.32 and we believe that the sample is representative of a primary Fe-rich mantle plume derived melt. In total, 75 experimental runs were carried out. Melting phase relations as well as compositions and modal proportions of all coexisting phases were successfully determined in 60 run products. Phase relations indicate that the ferropicrite melt was generated either at ∼ 2.2 GPa from an olivine-pyroxene residue or ∼ 5 GPa from a garnet-pyroxene residue. A low bulk-rock Al2O3 content (9 wt.%) and high [Gd/Yb]n ratio (3.1) are consistent with residual garnet in the ferropicrite melt source and favour high-pressure melting of garnet-pyroxenite. The garnet pyroxenite may represent subducted oceanic lithosphere entrained by the upwelling Tristan mantle plume starting-head. During adiabatic decompression, intersection of the garnet pyroxenite solidus at ∼ 5 GPa would occur at mantle potential temperatures of ∼ 1550° C. Subsequent melting of peridotite at ∼ 4.5 GPa may be restricted by the thick overlying sub-continental lithosphere such that dilution of the garnet-pyroxenite component would be significantly less than in intra-plate oceanic settings. This model accounts for the limited occurrence of ferropicrite magma in the initial stage of continental large igneous provinces and its absence in ocean-island basalt successions. 1 Allègre et al., Philosophical Transactions of the Royal Society of London A297, 447-477 (1980). 2 Gibson et al., Earth and Planetary Science Letters 174, 355-374 (2000). 3 Gibson, Earth and Planetary Science Letters 195, 59-74 (2002). Title: Numerical Simulations of Three-dimensional Coronal Magnetic Fields Resulting from the Emergence of Twisted Magnetic Flux Tubes Authors: Fan, Y.; Gibson, S. E. Bibcode: 2004ApJ...609.1123F Altcode: We present the results of MHD simulations in the low-β regime of the evolution of the three-dimensional coronal magnetic field as an arched, twisted magnetic flux tube emerges into a preexisting coronal potential magnetic arcade. We find that the line-tied emerging flux tube becomes kink-unstable when a sufficient amount of twist is transported into the corona. For an emerging flux tube with a left-handed twist (which is the preferred sense of twist for active region flux tubes in the northern hemisphere), the kink motion of the tube and its interaction with the ambient coronal magnetic field lead to the formation of an intense current layer that displays an inverse-S shape, consistent with the X-ray sigmoid morphology preferentially seen in the northern hemisphere. The position of the current layer in relation to the lower boundary magnetic field of the emerging flux tube is also in good agreement with the observed spatial relations between the X-ray sigmoids and their associated photospheric bipolar magnetic regions. We argue that the inverse-S-shaped current layer formed is consistent with being a magnetic tangential discontinuity limited by numerical resolution and thus may result in the magnetic reconnection and significant heating that causes X-ray sigmoid brightenings. Title: Numerical Simulations of 3D Coronal Magnetic Fields Resulting from the Emergence of Twisted Magnetic Flux Tubes Authors: Fan, Y.; Gibson, S. E. Bibcode: 2004AAS...204.1803F Altcode: 2004BAAS...36..682F We present MHD simulations in the low-β regime of the evolution of the 3D coronal magnetic field as an arched, twisted magnetic flux tube is transported into a pre-existing coronal potential magnetic arcade. It is found that the line-tied emerging flux tube becomes kink unstable when a sufficient amount of twist is transported into the corona. For an emerging flux tube with a left-handed twist (which is the preferred sense of twist for active region flux tubes in the northern hemisphere), the kink motion of the tube and its interaction with the ambient coronal magnetic field lead to the formation of an intense current layer which displays an inverse-S shape, consistent with the X-ray sigmoid morphology preferentially seen in the northern hemisphere. Our simulation results may explain the X-ray sigmoid brightenings that are observed during eruptive flares and confirm the prediction by previous topological studies that magnetic tangential discontinuities (or current sheets) should form along the so called ``bald-patch'' separatrix surface, across which the connectivity of the coronal magnetic field with the dense photosphere undergoes a sharp transition. Finally, we will also present simulations in a 3D spherical geometry of a CME-like eruption of the coronal magnetic field due to the kink instability of a twisted magnetic flux rope emerging into the corona. Title: Multi-Altitude Observations of a Coronal Jet Authors: Ko, Y. -K.; Raymond, J. C.; Gibson, S. E.; Alexander, D.; Strachan, L.; Holzer, T.; Gilbert, H.; St. Cyr, O. C.; Thompson, B. J.; Pike, C. D.; Burkepile, J.; Thompson, W.; Fletcher, L. Bibcode: 2004AAS...204.5413K Altcode: 2004BAAS...36..759K A coronal jet occurred on August 26, 1999 at the NW limb near a sigmoid active region (AR8668). This jet was observed by several instruments at the limb (SOHO/CDS, SOHO/EIT, TRACE, MLSO/CHIP, MLSO/PICS) and at 1.64 Ro (SOHO/UVCS). At the limb, this jet event has both low and high temperature components. The high temperature component appeared at the early phase (first 20 minutes) of the event along with the low temperature component while the latter seems to last long ( ∼ 1 hour) after the higher temperature component was gone. The line-of-sight motion at the limb started with red-shifted (by as much as 300 km/s) and turned blue-shifted (by as much as 200 km/s). At 1.64 Ro, the intensities of Lyα , Lyβ in the jet increased by a factor of several hundreds compared with the background corona. C III λ 977 line also brightened significantly. This indicates low temperature ( ∼ 1-2× 105 K) emission in the jet, while the intensities of O VI λ 1032 and O VI λ 1037 increased by a factor of as large as 8. Both UVCS and CDS data show evidence of heating at the early phase of the event. The line-of-sight velocity seen at 1.64 Ro started with ∼ 150 km/sec in blue shift and ended at ∼ 100 km/sec in red shift. This is apparently opposite to what were observed when the jet emerged from the limb. The Doppler dimming analysis indicates that the radial outflow speed correlates with the magnitude of the line-of-sight speed. Interestingly, UVCS observations at 2.33 and 2.66 Ro show no trace of the jet and LASCO observations also yield no firm sight of the jet. In this paper, we present the observations by these instruments and discuss the dynamical structure and physical properties of this jet. Y.-K. Ko acknowledges the support by NASA grant NAG5-12865. Title: Twist and Flare: The role of helical magnetic structures in the solar corona Authors: Gibson, S. Bibcode: 2004AAS...204.4603G Altcode: 2004BAAS...36..736G Solar explosive events such as coronal mass ejections (CMEs) and flares are commonly considered to be driven by the free magnetic energy stored in current carrying (twisted or sheared) coronal magnetic fields. Since it is presently not feasible to directly observe coronal magnetic fields, it is reasonable to turn to observations of flux-frozen solar plasma for evidence of such twisted magnetic field. Indeed, apparently twisted structures and rotating motions are not hard to find on the Sun. We must be cautious, however, in interpreting observations which are essentially projections of three-dimensional structures, and which highlight sub-regions of the magnetic field for specific physical reasons (for example, regions that are particularly dense or hot). In order to interpret such observations, it is essential to employ a three-dimensional, physical model that realistically simulates observable properties of the relationship between plasma and field. I will demonstrate how a model of a twisted magnetic flux rope emerging into a coronal magnetic field can be used to explain observed helical solar structures and dynamics. In particular, I will consider the structure, evolution, and relative location and orientation of S-shaped, or sigmoidal active regions and filaments. I will also discuss how the emerging flux rope can explain observed rotational and shearing motions at the solar photosphere. Finally, I will address how the emerging magnetic flux rope injects magnetic helicity into the corona, and how this drives dramatic coronal dynamics. Title: Three-dimensional coronal density structure: 1. Model Authors: Gibson, S. E.; Foster, D. J.; Guhathakurta, M.; Holzer, T.; St. Cyr, O. C. Bibcode: 2003JGRA..108.1444G Altcode: The three-dimensional (3-D) density structure of the solar corona is a fundamental boundary condition on the solar wind. Most easily applied models of the global coronal density have been restricted to date to axisymmetric 2-D cases. We present here a 3-D model made up of a superposition of multiple streamers, having distinct gaussian widths in longitude and latitude and both longitudinal and latitudinal dependence of the neutral lines implicit beneath the streamer cores. Nonradiality of streamers and solar B-angle tilt are also explicitly treated. We show how this simple model can capture many of the general properties of coronal white light observations and demonstrate how such a model can assist in the interpretation of the multiple views on coronal structures such as will be provided by the upcoming STEREO mission. Title: Low Density Magnetic Structures (Cavities) in the Solar Corona Authors: Foster, D.; Gibson, S.; Burkepile, J. Bibcode: 2003AGUFMSH41A..07F Altcode: Some helmet streamers in the low corona contain a density depleted region known as a cavity. Cavities form over magnetic polarity inversion lines, often referred to as filament channels, which frequently contain prominences. CMEs often erupt from helmet streamers, and are well associated with erupting prominences. The most common CME morpholgy is the well known loop cavity. Models have been proposed that identify these coronal cavities as low coronal manifestations of twisted magnetic flux ropes, which are then ejected into the solar wind as part of a CME. In order to begin to understand the magnetic structure of coronal cavities, this poster will first examine the frequency of quiescent cavities in the corona using white light observations from the Mark IV coronameter and eclipse photographs. Title: Observational consequences of a magnetic flux rope topology Authors: Gibson, S.; Barnes, G.; Demoulin, P.; Fan, Y.; Fisher, G.; Leka, K.; Longcope, D.; Mandrini, C.; Metcalf, T. Bibcode: 2003AGUFMSH42B0516G Altcode: We consider the implications of a magnetic flux rope topology for the interpretation of observations of sigmoidal active regions. A region of tangential magnetic discontinuities can be identified using techniques that determine a bald patch (BP) and corresponding separatrices or a quasi-separatrix layer (QSL) -- for a flux rope this region can be S-shaped, or sigmoidal. If such a region is physically driven, current sheets can form yielding conditions appropriate for reconnective heating. Using a numerical simulation of an emerging flux rope driven by the kink instability, Fan and Gibson (ApJL, 2003) showed that current sheets indeed formed a sigmoidal surface. In this poster we will demonstrate that the current sheets formed on the BP and BP separatrices. Moreover, we will use the results of the numerical simulation as proxies for observations: specifically the simulated field at the photosphere as proxy for the magnetic boundary condition, the sigmoidal current sheets as proxy for the X-ray active region emission, and the location of dipped magnetic field lines as proxy for a filament. We will then consider to what extent such observations might be used to understand and constrain the basic properties of the coronal field. Title: Development of 2D MHD Self-Consistent Empirical Model of the Corona and Solar Wind Authors: Sittler, E. C.; Ofman, L.; Gibson, S.; Holzer, T.; Davila, J.; Guhathakurta, M. Bibcode: 2003AGUFMSH42D..07S Altcode: We are developing a 2D MHD self-consistent empirical model of the solar corona and solar wind. We constrain the solution using empirically determined estimates of the effective pressure for the momentum equation and effective heat flux for the energy equation provided from coronagraph data and Ulysses plasma and magnetic field data. Our solutions are steady state and do not use a polytrope which we know is not valid in the solar corona. We have been able to achieve preliminary convergence. We will present the results of an error analysis. Our results are presently only valid during solar minimum, but are generalizing so it can be used during the transition toward solar maximum (i.e., three current sheets). We will also present some preliminary results which will allow us to apply our solutions to solar maximum conditions. Title: Development of Multidimensional MHD Model for the Solar Corona and Solar Wind Authors: Sittler, E. C.; Ofman, L.; Gibson, S.; Guhathakurta, M.; Davila, J.; Skoug, R.; Fludra, A.; Holzer, T. Bibcode: 2003AIPC..679..113S Altcode: We are developing a time stationary self-consistent 2D MHD model of the solar corona and solar wind that explicitly solves the energy equation, using a semi-empirical 2D MHD model of the corona to provide an empirically determined effective heat flux qeff (i.e., the term effective means the possible presence of wave contributions). But, as our preliminary results indicate, in order to achieve high speed winds over the poles we also need to include the empirically determined effective pressure Peff as a constraint in the momentum equation, which means that momentum addition by waves above 2 RS are required to produce high speed winds. At present our calculations do not include the Peff constraint. The estimates of Peff and qeff come from the semi-empirical 2D MHD model of the solar corona by Sittler and Guhathakurta (1999a,2002) which is based on Mk-III, Skylab and Ulysses observations. For future model development we plan to use SOHO LASCO, CDS, EIT, UVCS and Ulysses data as constraints for our model calculations. The model by Sittler and Guhathakurta (1999a, 2002) is not a self-consistent calculation. The calculations presented here is the first attempt at providing a self-consistent calculation based on empirical constraints. Title: The Emergence of a Twisted Magnetic Flux Tube into a Preexisting Coronal Arcade Authors: Fan, Y.; Gibson, S. E. Bibcode: 2003ApJ...589L.105F Altcode: To investigate the dynamic evolution of a coronal magnetic field in response to the emergence of significantly twisted magnetic structures, we perform MHD simulations in the low-β regime of the emergence of a twisted magnetic flux tube into a preexisting coronal potential magnetic arcade. Our simulation of a twisted flux tube, which when fully emerged contains a twist of 1.875×2π field-line rotation about the axis between the anchored footpoints, leads to a magnetic structure with substantial writhing of the tube axis (with an apex rotation >90°) as a result of the nonlinear evolution of the kink instability. For an emerging tube with a left-handed twist (which is the preferred sense of twist for active regions in the northern hemisphere), the writhing of the tube is also left-handed, producing a forward-S shape for the tube axis as viewed from the top, which is opposite to the inverse-S-shaped X-ray sigmoid structures preferentially seen in the northern hemisphere. However, we find that the writhing motion of the tube and its interaction with the ambient coronal magnetic field also drive the formation of an intense current layer that displays an inverse-S shape, consistent with the shape of X-ray sigmoids. Title: The Emergence of a Twisted Magnetic Flux Tube into a Pre-existing Coronal Arcade Authors: Fan, Y.; Gibson, S. E. Bibcode: 2003SPD....34.0416F Altcode: 2003BAAS...35..813F To investigate the dynamic evolution of coronal magnetic field in response to the emergence of significantly twisted magnetic structures, we perform MHD simulations in the low-β regime of the emergence of a twisted magnetic flux tube into a pre-existing coronal potential magnetic arcade. Our simulation of a twisted flux tube, which when fully emerged, contains a twist of 1.875 x 2 π field-line rotation about the axis between the anchored footpoints, leads to a magnetic structure with substantial writhing of the tube axis (apex rotation > 90o) as a result of the non-linear evolution of the kink instability. For an emerging tube with a left-handed twist (which is the preferred sense of twist for active regions in the northern hemisphere), the writhing of the tube is also left-handed, producing a forward S-shape for the tube axis as viewed from the top, which is opposite to the inverse S-shaped X-ray sigmoid structures preferentially seen in the northern hemisphere. However we find that the writhing motion of the tube and its interaction with the ambient coronal magnetic field also drives the formation of an intense current layer which displays an inverse S-shape, consistent with the shape of X-ray sigmoids. We compare the resulting current layer from the dynamic simulation with an analysis of the separatrix surface between winding and non-winding fields at various states of emergence.

The National Center for Atmospheric Research is sponsored by the National Science Foundation. This work is supported in part by AFOSR grant F49620-02-0191. Title: The "Whole Sun Month" Campaigns As a Prototype for IHY Authors: Thompson, B. J.; Biesecker, D. A.; Breen, A. R.; Gibson, S. E. Bibcode: 2003EAEJA....11571T Altcode: The International Heliophysical Year (IHY) in 2007 will consist of a series of coordinated observations combining data and models from an expansive group of international participants. Campaigns will be planned to target all aspects of heliophysics, including solar and interplanetary physics, geospace science and the climatary impact on Earth. These campaigns will require extensive coordination to ensure that available ground-based and space missions are utilized to the greatest scientific benefit. The "Whole Sun Month" campaigns serve as an excellent prototype for IHY. The first Whole Sun Month campaign (10 August - 8 September 1996) consisted of an entire month of coordinated solar and heliospheric observations, followed by workshops which combined the analysis of the campaign data with the utilization of these data to constrain interpretive 3-D models solar and heliospheric structure. The subsequent campaigns (in 1998 and 1999) targetted more specific topics, again allowing a broad base of participants to establish a comprehensive base of observations for model interpretation. The many scientific successes of the Whole Sun Month campaigns (publications, workshops, model refinement and ongoing collaborations) and the framework of campaign coordination provides an excellent basis for the planning of IHY campaigns. We will discuss the campaigns in detail and begin an outline for how the campaigns could be expanded to incorporate more observations and a greater timeline for IHY. Title: Empirically Constrained Multidimensional MHD Model for the Solar Corona and Solar Wind Authors: Sittler, E. C.; Ofman, L.; Gibson, S.; Guthathakurta, M.; Skoug, R.; Fludra, A.; Davila, J.; Holzer, T. Bibcode: 2002AGUFMSH21A0502S Altcode: We are developing a time stationary self-consistent 2D MHD model of the solar corona and solar wind that explicitly solves the energy equation, using a semi-empirical 2D MHD model of the corona to provide an empirically determined effective heat flux qeff (i.e., the term effective means the possible presence of wave contributions) for the energy equation and effective pressure Peff for the momentum equation. Preliminary results indicated that in order to achieve high speed winds over the poles we not only needed to use qeff in the energy equation, but also needed to include the empirically determined effective pressure Peff as a constraint in the momentum equation, which means that momentum addition by waves above 2 RS are required to produce high speed winds. A solution which only included qeff showed high acceleration over the poles below 2 RS, but then drooped above that radial distance indicating we needed momentum addition above that height to get high speed flows over the poles. We will show new results which include the added constraint of Peff in the momentum equation. This method will allows us to estimate the momentum addition term due to waves as a function of height and latitude within the corona. The estimates of Peff and qeff come from the semi-empirical 2D MHD model of the solar corona by Sittler and Guhathakurta (1999, 2002) which is based on Mk-III, Skylab and Ulysses observations. For future model development we plan to use SOHO LASCO, CDS, EIT, UVCS, Spartan 201-05 and Ulysses data as constraints for our model calculations. The model by Sittler and Guhathakurta (1999, 2002) is not a self-consistent calculation. The calculations presented here are a continuing effort to provide a self-consistent calculation based on empirical constraints. Title: Indications and implications of twisted magnetic flux in the corona Authors: Gibson, S. E.; Fan, Y.; Jain, R.; Low, B. Bibcode: 2002AGUFMSH52A0446G Altcode: The question of whether magnetic flux ropes are fundamental to CMEs and their precursors will be addressed using a combination of analytic and numerical models, along with coronal observations. We have developed computational tools for evaluating observable properties of modeled magnetic flux ropes suspended in the corona, such as separatrix surfaces and dipped magnetic fields. We have also developed numerical models to demonstrate how a flux rope emerging into an overlying coronal magnetic arcade will relax to a force-free configuration, with associated formation of current sheets. Using the results of these two parallel studies, we will directly compare separatrix surfaces determined from an analytic (non-force-free) equilibrium model to the current sheets formed during numerical force-free relaxation of the same initial field configuration. We will then consider these in the context of observed X-ray sigmoid structures. We have also developed mathematical methods for determining the magnetic free energy in analytic models of both magnetic flux ropes, as well as sheared field configurations that contain no rope. We will compare the free energies thus determined for both sheared and twisted fields, as functions of spatial size, magnetic field strength, and degree of shear or twist. We will consider the implications of these results for the energetics of coronal mass ejections. Title: 3-Dimensional Density Model of the Solar Corona Authors: Foster, D.; Gibson, S. E.; Holzer, T.; Guhathakurta, M. Bibcode: 2002AGUFMSH52A0448F Altcode: We present a 3-D density model of the solar corona, determined from synoptic maps of Carrington Rotations 1942-3 (22 Oct. 1998 - 18 Nov. - 15 Dec. 1998). The rotations we have chosen include the time period of the SPARTAN 201-05 flight (Nov. 1-3, 1998), which had unprecedented spatial and temporal coverage of the white light corona. These rotations are also useful because they occur at a point in the solar cycle (ascending phase) that is complex enough to exhibit interesting 3-D structure, yet not so dynamic that a meaningful density model cannot be constructed using the rotation of the sun to provide the 3-D information. Along with SPARTAN data, we consider observations made by the Mark IV instrument in the Mauna Loa Observatory, and also SOHO/LASCO and EIT observations. Our analytic model, an extension of the axisymmetric model of Guhathakurta et al (1996), allows for multiple streamers varying in both latitude and longitude, and explicitly treats nonradial streamers. Our 3-D model will be useful for testing analysis techniques for the upcoming STEREO mission. We will also compare its structure to magnetic field extrapolation models, coronal hole boundaries, and magnetic neutral lines. Title: Solar Synoptic Maps as a Means to Study the Global Sun Authors: de Toma, G.; Gibson, S. E.; Jenne, R. L.; Arge, C. N. Bibcode: 2002AGUFMSH51A0432D Altcode: Solar synoptic maps (often referred as Carrington maps) are maps of the Sun in latitude versus longitude built by merging together solar observations taken during one solar rotation. They are an efficient method to represent the Sun as it appears during a rotation yielding a global view of solar structures, such as active regions, coronal holes, and helmet streamers. They provide a clear and effective way to study evolutionary patterns on the Sun and to compare different solar datasets over long periods of time. Because of their ability to display a large number of data in a concise way, solar synoptic maps have been popular for many years. The availability of modern instruments (both in space and on the ground) that can provide consistent and calibrated measurements for many years has renewed the interest in this data format. We believe there is a need for the solar-terrestrial community to agree on a standard format for synoptic maps of the Sun. Such a format should be discussed and defined in parallel with the effort of the Solar Virtual Observatory. At the High Altitude Observatory (HAO), we are developing a public database of solar synoptic maps for the solar observations made at Mauna Loa Solar Observatory (MLSO). The database will include observations of the solar corona in visible light and of the solar chromosphere in the HeI 1083nm and Hα lines. In this paper, we present examples of MLSO solar synoptic maps and compare them with other solar synoptic maps to illustrate the scientific use and flexibility of this data format. Title: Magnetic flux ropes: Would we know one if we saw one? Authors: Gibson, S. E.; Low, B. C.; Leka, K. D.; Fan, Y.; Fletcher, L. Bibcode: 2002ESASP.505..265G Altcode: 2002IAUCo.188..265G; 2002solm.conf..265G There has been much debate lately about whether twisted magnetic flux ropes exist in the corona. When asked for observational evidence of them, the temptation is to show images of apparently twisted structures. However, we must be very careful of projection effects in interpreting these observations. Two critical aspects of understanding how we might observe flux ropes are 1) the 3D nature of the flux rope, and 2) physically, which bits are visible and for what reasons? In this paper we will use a simple but physically reasonable 3D analytic model to address these two issues, and develop techniques that can in future be used on more general models, both analytic and numerical. Title: The Structure and Evolution of a Sigmoidal Active Region Authors: Gibson, S. E.; Fletcher, L.; Del Zanna, G.; Pike, C. D.; Mason, H. E.; Mandrini, C. H.; Démoulin, P.; Gilbert, H.; Burkepile, J.; Holzer, T.; Alexander, D.; Liu, Y.; Nitta, N.; Qiu, J.; Schmieder, B.; Thompson, B. J. Bibcode: 2002ApJ...574.1021G Altcode: Solar coronal sigmoidal active regions have been shown to be precursors to some coronal mass ejections. Sigmoids, or S-shaped structures, may be indicators of twisted or helical magnetic structures, having an increased likelihood of eruption. We present here an analysis of a sigmoidal region's three-dimensional structure and how it evolves in relation to its eruptive dynamics. We use data taken during a recent study of a sigmoidal active region passing across the solar disk (an element of the third Whole Sun Month campaign). While S-shaped structures are generally observed in soft X-ray (SXR) emission, the observations that we present demonstrate their visibility at a range of wavelengths including those showing an associated sigmoidal filament. We examine the relationship between the S-shaped structures seen in SXR and those seen in cooler lines in order to probe the sigmoidal region's three-dimensional density and temperature structure. We also consider magnetic field observations and extrapolations in relation to these coronal structures. We present an interpretation of the disk passage of the sigmoidal region, in terms of a twisted magnetic flux rope that emerges into and equilibrates with overlying coronal magnetic field structures, which explains many of the key observed aspects of the region's structure and evolution. In particular, the evolving flux rope interpretation provides insight into why and how the region moves between active and quiescent phases, how the region's sigmoidicity is maintained during its evolution, and under what circumstances sigmoidal structures are apparent at a range of wavelengths. Title: Self-consistent 2D MHD modeling of multi-streamer coronal structures Authors: Ofman, L.; Sittler, E. C.; Gibson, S.; Holzer, T. E.; Guhathakurta, M. Bibcode: 2002AGUSMSH21B..02O Altcode: Recently, a semi-empirical 2D MHD model of the solar corona was constructed by Sittler and Guhathakurta [1999]. The model uses an empirical electron density and empirical magnetic field during solar minimum as input to the conservation equations of mass, momentum, and energy to derive an empirical effective heat flux, or empirical heating function. This semi-empirical model is not a self-consistent calculation. We explore the possibility of developing a self-consistent model that uses the empirical heating function as a constraint for the calculations. This allows us to solve the energy equation without use of a polytrope which we know does not apply near the Sun. For our initial attempt we use the empirically derived magnetic field model obtained from observed streamer topologies and Ulysses boundary conditions to initialize our self-consistent 2D MHD model of the solar corona. We solve the thermally conductive energy equations with an empirical heating function, and obtain 3-streamer structure with self-consistent magnetic field, current-sheets, solar wind outflow, density, and temperature. We compare the results of the thermally conductive model to the polytropic model, and to the empirical model. We find that the self-consistent magnetic field structure is more realistic then the empirical model. We find that the thermally conductive streamers result in more diffuse current-sheets than in the polytropic model. We also find that the heating function reduces the heliocentric distance of the streamers' cusp, and produces more rapid acceleration of the solar wind in the thermally conductive model then in the polytropic model, consistent with observations. We investigate the effect of various forms of the heating function, and of an empirically derived heat flux on the solutions. Title: Emergence of twisted magnetic flux into the corona Authors: Gibson, S.; Low, B. C.; Fan, Y.; Fletcher, L. Bibcode: 2002AAS...200.3603G Altcode: 2002BAAS...34..693G The interaction between emerging magnetic structures and preexisting overlying coronal structures will be addressed using a combination of observations and physical models that incorporate a range of twisted magnetic topologies. Solar explosive events such as coronal mass ejections (CMEs) and flares are commonly considered to be driven by the free magnetic energy stored in twisted (current carrying) coronal magnetic fields. Understanding the origin and the three-dimensional nature of these twisted coronal magnetic structures is a crucial step towards explaining and predicting CMEs and flares. One possible and appealing picture is that the twisted coronal magnetic structures form as a result of the emergence of twisted magnetic flux tubes from the solar interior. We might imagine a scenario where a flux rope forms sub-photospherically, emerges through the photosphere, exists in the corona until it loses its stability and erupts in a CME which moves out through interplanetary space until ultimately impacting on the Earth's magnetosphere. Attractively simple as this picture is, reality is likely to be more complicated since the various regimes are physically very different and pre-existing structures would get in the way of our traveling flux rope. We will concentrate on joining up two of these regimes, by considering how a flux rope could rise from beneath the photosphere and emerge into the corona, interacting with pre-existing coronal structures. We will approach this problem by using a combination of numerical models of the flux rope emergence from beneath the photosphere, analytic models of coronal dynamic and equilibrium magnetic structures, and photospheric and coronal observations of the 3-d structure and evolution of a so-called "sigmoidal", or S-shaped active region. In so doing we hope to gain essential insight into how twisted magnetic fields are formed and how they could be ultimately removed from the solar corona. Title: Coronal mass ejection Authors: Gibson, Sarah Bibcode: 2002bhty.confE..11G Altcode: No abstract at ADS Title: Sigmoidal diagnostics with SOHO/CDS Authors: Del Zanna, G.; Gibson, S. E.; Mason, H. E.; Pike, C. D.; Mandrini, C. H. Bibcode: 2002AdSpR..30..551D Altcode: During the third Whole Sun Month Campaign (August 18 - September 14, 1999), the evolution of the active region NOAA 8668 was followed during its meridian passage and at the limb (Sigmoid JOP 106), with simultaneous observations with the Solar and Heliospheric Observatory (SOHO), and with other instruments, both satellite and ground-based. On August 21st, a small flare, associated with a brightening of the sigmoidal structure, occurred. SOHO Coronal Diagnostic Spectrometer (CDS) observations of this small flare are presented. Coronal temperatures and densities of the sigmoid are estimated. High transition region densities (in the range 2.5-7 × 10 11 cm -3), obtained using O IV, are present in the brightenings associated with the flare. At coronal level, high temperatures of at least 8 MK were reached, as shown by strong Fe XIX emission. After this small flare, relatively strong blue-shifts (⋍ 30 km/s) are observed in coronal lines, located at the two ends of a small loop system associated with the sigmoid. Title: Interpreting observations of the three-dimensional coronal mass ejection Authors: Gibson, S. E.; Burkepile, J.; deToma, G. Bibcode: 2001AGUFMSH12B0751G Altcode: The upcoming STEREO mission will provide observations of coronal mass ejections (CMEs) from multiple points of view, yielding unprecedented clues to their three-dimensional structure. It is therefore crucial to develop data analysis tools to interpret these observations. We will present a description of such a data analysis method. Specifically, we will approach the "forward problem" by considering density models of CMEs which can be integrated along different lines of sight to yield different observable white light distributions. The resulting white light distributions could in future be compared directly to the multiple viewpoints of STEREO, but for now will be compared to a range of existing CME observations in order to gain information on which density models best reproduce observed features. We will also describe how genetic algorithm techniques can be applied to efficiently find the best models and model parameters to match a given set of observations. Title: Global Solar Wind Structure from Solar Minimum to Solar Maximum: Sources and Evolution Authors: Gibson, S. E. Bibcode: 2001SSRv...97...69G Altcode: During the past few years, significant progress has been made in identifying the coronal sources of structures observed in the solar wind. This recent work has been facilitated by the relative simplicity and stability of structures during solar minimum. The challenge now is to continue to use coordinated coronal/solar wind observations to study the far more complicated and time-evolving structures of solar maximum. In this paper I will review analyses that use a wide range of observations to map out the global heliosphere and connect the corona to the solar wind. In particular, I will review some of the solar minimum studies done for the first Whole Sun Month campaign (WSM1), and briefly consider work in progress modeling the ascending phase time period of the second Whole Sun Fortnight campaign (WSF) and SPARTAN 201-05 observations, and the solar maximum third Whole Sun Month campaign (WSM3). In so doing I hope to demonstrate the increase in complexity of the connections between corona and heliosphere with solar cycle, and highlight the issues that need to be addressed in modeling solar maximum connections. Title: 3-D and twisted: magnetic field topologies of CMEs Authors: Gibson, S. E.; Low, B. Bibcode: 2001AGUSM..SH41C08G Altcode: Physical models admitting a range of magnetic topologies within a coronal mass ejection (CME) will be compared to observations. The nature of CME magnetic fields and their relationships with their plasma distributions are largely unknown, because coronal magnetic fields are not directly observed and the three-dimensional (3D) morphology of the CME can, at best, be inferred from CME density and temperature structures observed as projections onto the plane of the sky. Important insights can be obtained from the relationship between CMEs observed at the solar limb and those observed projected on the solar disk. To study this relationship an MHD model of the 3-D CME is required. This was carried out using a 3-D analytically exact MHD model which treats the CME magnetic field as a spheromak-type flux rope magnetic field pushing its way out of a global open magnetic field (Gibson and Low, ApJ, 493, 460, 1998 & JGR, 105, 18187, 2000). This model shows that such observed white-light limb features as three-part CMEs and U-shaped ``disconnected'' regions, and on-disk structures such as twin dimmings (also referred to as transient coronal holes), and sigmoidal filaments and X-ray loops can be self-consistently explained in terms of the same 3D magnetic morphology and plasma structure viewed in different projections. Further development in this work, including variations of the original model to allow for a greater variety of admissible magnetic topologies, will be reported. Title: Dynamics of Expanding Flux Ropes in Coronal Mass Ejections Authors: Manchester, W. B.; Gombosi, T. I.; De Zeeuw, D. L.; Powell, K. G.; Low, B.; Gibson, S. E. Bibcode: 2001AGUSM..SH22A07M Altcode: We present a three-dimensional numerical ideal magnetohydrodynamics (MHD) model describing the time-dependent expulsion of a CME form the solar corona. The CME is driven by a twisted magnetic flux rope that is anchored at both ends in the photosphere and embedded in a open bipolar magnetic field. We follow the evolution of the CME from the low corona as it makes its way through surrounding magnetic fields anchored to the sun. We explore the dynamics of the expanding flux rope in 3D space to determine significant MHD effects. This model employs a variety of initial state similar to that suggested by Gibson and Low as a means of producing several notable features of CME's such as a coronal cavity and bright core seen in white-light coronagraphs.Our numerical model is in contrast to traditional CME models that incorporate force-free bipolar magnetic fields. The flux rope configuration offers the advantage of greater magnetic free energy to drive the CME and produces plasma outflows that qualitatively match white-light coronagraph observations of CME structure. Title: Source Region of High and Low Speed Wind during the Spartan 201-05 Flight Authors: Guhathakurta, Madhullika; Sittler, Ed, Jr.; Fisher, Richard; Kucera, Therese; Gibson, Sarah; McComas, Dave; Skoug, Ruth Bibcode: 2001SSRv...97...45G Altcode: The large-scale coronal magnetic fields of the Sun are believed to play an important role in organizing the coronal plasma and channeling the high and low speed solar wind along the open magnetic field lines of the polar coronal holes and the rapidly diverging field lines close to the current sheet regions, as has been observed by the instruments aboard the Ulysses spacecraft from March 1992 to March 1997. We have performed a study of this phenomena within the framework of a semi-empirical model of the coronal expansion and solar wind using Spartan, SOHO, and Ulysses observations during the quiescent phase of the solar cycle. Key to this understanding is the demonstration that the white light coronagraph data can be used to trace out the topology of the coronal magnetic field and then using the Ulysses data to fix the strength of the surface magnetic field of the Sun. As a consequence, it is possible to utilize this semi-empirical model with remote sensing observation of the shape and density of the solar corona and in situ data of magnetic field and mass flux to predict values of the solar wind at all latitudes through out the solar system. We have applied this technique to the observations of Spartan 201-05 on 1 2 November, 1998, SOHO and Ulysses during the rising phase of this solar cycle and speculate on what solar wind velocities Ulysses will observe during its polar passes over the south and the north poles during September of 2000 and 2001. In order to do this the model has been generalized to include multiple streamer belts and co-located current sheets. The model shows some interesting new results. Title: Three-dimensional and twisted: An MHD interpretation of on-disk observational characteristics of coronal mass ejections Authors: Gibson, S. E.; Low, B. C. Bibcode: 2000JGR...10518187G Altcode: A physical interpretation of observed coronal ``on-disk'' manifestations of an Earth-directed coronal mass ejection (CME) is presented. The fundamental question of how the CME's magnetic field and its plasma distribution are related is largely unanswered, because a crucial piece of the puzzle, that is the three-dimensional (3-D) morphology of the CME, remains difficult to ascertain so long as coronal observations are limited to projections onto a single plane of the sky. In order to understand the relationship between observations of CMEs projected at the solar limb and those projected on the solar disk, some sort of model of the 3-D CME is required. In this paper we address both the question of the 3-D morphology of the CME and the more fundamental question of the nature of the plasma-magnetic field relationship, by comparing the limb and on-disk CME representations of an analytic 3-D MHD model based on a spheromak-type flux rope magnetic field configuration. In particular, we show that the morphology of twin dimmings (also referred to as transient coronal holes) observed in X ray and EUV can be reproduced by the CME model as the on-disk projection of the prominence cavity modeled for limb CMEs. Moreover, the bright core of a limb CME, generally corresponding to the material in an erupting prominence, may be interpreted to be the S-shaped central core of the modeled on-disk CME, splitting the cavity into twin dimmings when observed head-on without obstruction. The magnetic field structure of this central core exhibits many of a filament's magnetic field features required to match observations. Finally, we consider the nature of S-shaped filaments and X-ray ``sigmoids'' in the context of the model, in terms of localized heating and cooling acting on the modeled CME magnetic field structure. Title: SOHO/UVCS Observations of a Coronal Jet During the Third Whole Sun Month Campaign Authors: Ko, Y. -K.; Raymond, J.; Gibson, S.; Strachan, L.; Alexander, D.; Fletcher, L.; Holzer, T.; Gilbert, H.; Burkepile, J.; St. Cyr, C.; Thompson, B. Bibcode: 2000SPD....31.0271K Altcode: 2000BAAS...32R.823K On August 26 1999, a coronal jet occurred at the north west limb near a sigmoid active region which has been the target for a joint observation plan during the third Whole Sun Month Campaign. This jet was observed by several instruments at the limb (SOHO/CDS, SOHO/EIT, TRACE, MLSO/CHIP, MLSO/PICS), at 1.7 Ro (SOHO/UVCS), and at the outer corona (SOHO/LASCO). At 1.7 Ro, the intensities of Lyman alpha, Lyman beta in the jet increased by as large a factor of 100 compared with the background corona, while those for O VI 1032 and O VI 1037 increased by a factor of 2. C III 977 line also brightened significantly. The line shift in the lines indicates that the line-of-sight velocity in the jet started from 150 km/sec blue shift and ended at 120 km/sec red shift. This line-of-sight motion seen at 1.7 Ro apparently was opposite that observed when the jet emerged from the limb. In this paper, we present the observation by SOHO/UVCS and discuss the dynamic structure and physical properties of this jet as it passed through 1.7 Ro. Comparisons will be shown with the observations from other instruments. This work is supported by NASA Grant number NAG5-7822. Title: Source Region of High and Low Speed Wind During the Flight of Spartan 201-05 Authors: Guhathakurta, M.; Sittler, E.; Fisher, R.; Gibson, S.; Kucera, T. Bibcode: 2000SPD....31.0903G Altcode: 2000BAAS...32..841G The large scale coronal magnetic fields of the Sun are believed to play an important role in organizing the coronal plasma and channeling the high and low speed solar wind along the open magnetic field lines of the polar coronal holes and the rapidly diverging field lines close to the current sheet regions, as has been observed by the instruments aboard the Ulysses spacecraft from 3/92-3/97. We have performed a study of this phenomena within the framework of a semi-empirical model of the coronal expansion and solar wind using Spartan201-03, September, 1995, SOHO and Ulysses observations during the quiescent phase of the past solar cycle. Key to this understanding is the demonstration that the white light coronagraph data can be used to trace out the topology of the coronal magnetic field and then using the Ulysses data to fix the strength of the surface magnetic field of the Sun. As a consequence, it is possible to utilize this semi-empirical model with remote sensing observation of the shape and density of the solar corona and in situ data of magnetic field and mass flux to predict values of the solar wind at all latitudes throuhtout the solar system. We will apply this technique to the observations of Spartan 201-05 on 1-2 November, 1998, SOHO and Ulysses during the rising phase of this solar cycle and speculate on what solar wind velocities Ulysses will observe during its polar passes over the south and the north poles during September of 2000 and 2001. This work has been funded by NASA SR & T. Title: The Third Whole Sun Month Campaign - Coronal Synoptic Maps Authors: Biesecker, D. A.; Gibson, S. E.; Alexander, D.; Fludra, A.; Hoeksema, J. T.; Panasyuk, A. V.; Thompson, B. J. Bibcode: 2000SPD....31.0239B Altcode: 2000BAAS...32..817B Observations for the Third Whole Sun Month Campaign were made throughout Carrington Rotation 1953 (August 18-September 14, 1999). As in the first campaign; the primary focus is on understanding the large scale solar corona and the connections to interplanetary space over a full solar rotation. The fundamental notion of these campaigns is that the observations are available for anyone to work with. In this poster, we use synoptic maps to show the morphology of the solar corona during CR1953 at a variety of wavelengths, heights, and temperatures. Data are shown from YOHKOH SXT, MLSO Mk4, and SOHO MDI, CDS, UVCS, EIT, and LASCO. The current campaign differs from the first campaign in that near solar maximum conditions prevailed. We held one workshop in order to get organized and begin collaborations. The planned studies will include determining the plasma parameters in various coronal structures and in modeling the structure of the coronal magnetic fields. In addition, we had the opportunity to study how a "sigmoidal" active region evolved as it crossed the solar disk and affected the global corona through a series of flares and eruptive events, and to obtain detailed observations of its structure over a wide range of heights and temperatures. We will be holding future workshops to analyze the data and work on models. We invite you to participate in this campaign or at least see our current plans for data analysis and modeling. Title: Latitudinal dependence of outflow velocities from O VI Doppler dimming observations during the Whole Sun Month Authors: Strachan, Leonard; Panasyuk, Alexander V.; Dobrzycka, Danuta; Kohl, John L.; Noci, Giancarlo; Gibson, Sarah E.; Biesecker, Douglas A. Bibcode: 2000JGR...105.2345S Altcode: Empirical determinations of outflow velocities in the solar corona provide a much needed constraint, along with density and temperature determinations, of the acceleration and heating mechanisms in the extended corona. Much progress has been made on density determinations from white light polarized brightness observations but outflow velocities have been more difficult to determine. We present the first determinations of outflow velocities versus height and latitude based on a three-dimensional (3-D) reconstruction of the O VI 1032 and 1037 Å emissivities. The Doppler dimming (and pumping) of the local emissivities give true localized outflow velocities at the selected locations in the extended corona from ~ 1.75 to 2.75 solar radii. The velocities are based on an empirical model of the corona which is constrained by the reconstructed O VI emissivities derived from the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) synoptic observations and by electron density determinations based on white light measurements from the SOHO Large Angle Spectroscopic Coronagraph (LASCO) and Mauna Loa Solar Observatory (MLSO) Mk III coronameter. Title: Searching for Sigmoids in SOHO/CDS Authors: Gibson, Sarah; Mason, Helen; Pike, Dave; Young, Peter Bibcode: 1999ESASP.446..331G Altcode: 1999soho....8..331G Sigmoidal structures observed in X-rays have been shown to be precursors to CMEs, existing in some cases for several days before an eruption (Sterling and Hudson 1997,ApJ,491,L55; Canfield et al, 1999, GRL, 26, 6, 627). While these S-shaped structures are most apparent in X-ray active region observations, they may be manifestations of a more general helical magnetic structure having observational signatures at other wavelengths. We will present preliminary results of a survey search for sigmoidal structures and other CME tracers in archived SOHO/CDS data for a series of active regions known to contain erupting sigmoidal structures in X-ray observations. We are particularly interested in determining the relative locations and temperatures of these tracers, and will see to what extent the data answers questions such as, if S shapes are observed at different wavelengths do they line up, or is there a spatial displacement and/or rotation of angle of S that corresponds with height/temperature variation ? How does the appearance of the region vary over the lifetime of the observed x-ray sigmoidal structure ? After an eruption, how much if any of the S shape remains, and at what spatial and spectral locations ? We will use the results of this comparison survey to consider what the implications are for the underlying magnetic field structure, and the location and variation of heating throughout it. Title: The Three-dimensional Coronal Magnetic Field during Whole Sun Month Authors: Gibson, S. E.; Biesecker, D.; Guhathakurta, M.; Hoeksema, J. T.; Lazarus, A. J.; Linker, J.; Mikic, Z.; Pisanko, Y.; Riley, P.; Steinberg, J.; Strachan, L.; Szabo, A.; Thompson, B. J.; Zhao, X. P. Bibcode: 1999ApJ...520..871G Altcode: Combining models and observations, we study the three-dimensional coronal magnetic field during a period of extensive coordinated solar observations and analysis known as the Whole Sun Month (WSM) campaign (1996 August 10-September 8). The two main goals of the WSM campaign are addressed in this paper, namely, (1) to use the field configuration to link coronal features observed by coronagraphs and imaging telescopes to solar wind speed variations observed in situ and (2) to study the role of the three-dimensional coronal magnetic field in coronal force balance. Specifically, we consider how the magnetic field connects the two fastest wind streams to the two regions that have been the main foci of the WSM analysis: the equatorial extension of the north coronal hole (known as the Elephant's Trunk) and the axisymmetric streamer belt region on the opposite side of the Sun. We then quantitatively compare the different model predictions of coronal plasma and solar wind properties with observations and consider the implications for coronal force balance and solar wind acceleration. Title: The north-south coronal asymmetry with inferred magnetic quadrupole Authors: Osherovich, V. A.; Fainberg, J.; Fisher, R. R.; Gibson, S. E.; Goldstein, M. L.; Guhathakurta, M.; Siregar, E. Bibcode: 1999AIPC..471..721O Altcode: 1999sowi.conf..721O The quiet corona at times close to solar minimum shows a striking north-south asymmetry which suggests that neither dipole-like nor octupole-like fields are sufficient to describe the global coronal magnetic field. We believe that such phenomena reflect the asymmetry of the intrinsic magnetic field of the sun as a star; this weak field is usually obscured by active regions. Empirical models for spherical corona (at solar maximum) and for ellipsoidal corona (at solar minimum) have been established. We extend the existing classification to include an empirical model for the quiet solar corona with strong north-south asymmetry. We show examples of such asymmetric corona in the green line for three different solar minima and evolution of corona from almost ellipsoidal type to corona with strong north-south asymmetry ``bald man with double beard''). A theoretical model (1984) of Osherovich et al. (1) relates such asymmetry to the existence of a significant quadrupole term in the global magnetic field of the sun. According to this model, the size of northern and southern polar coronal holes is affected differently by a quadrupole term which creates asymmetry in the magnetic and thermodynamic parameters as well as in the velocity of the outflow from the two polar regions. Title: Modeling CMEs in three dimensions using an analytic MHD model Authors: Gibson, Sarah E.; Alexander, David; Biesecker, Doug; Fisher, Richard; Guhathakurta, Madhulika; Hudson, Hugh; Thompson, B. J. Bibcode: 1999AIPC..471..645G Altcode: 1999sowi.conf..645G Because coronal mass ejections (CMEs) are viewed in projection, it is difficult to determine their three-dimensional nature. We use an analytic model of CMEs as an example of a fully three-dimensional magnetic field structure in MHD force balance with an emerging CME. We present the CME magnetic field and its associated density structure, seen projected at the limb from two viewing angles perpendicular to the plane of the sky, and emerging from disk center representing ``earth-directed'' CME events. The range of CME structures thus produced compares well to existing CME white-light coronagraph and full disk EUV and X-ray observations. In particular, we find that both 3-part ``front-cavity-core'' and ``U-shaped'' white light CMEs, as well as the twin dimmings (also referred to as transient coronal holes) observed in X-ray and EUV, can successfully be reproduced by the CME model. All of these structures are a direct consequence of a single three-dimensional magnetic field topology, viewed from different directions. Title: Solar minimum streamer densities and temperatures using Whole Sun Month coordinated data sets Authors: Gibson, S. E.; Fludra, A.; Bagenal, F.; Biesecker, D.; del Zanna, G.; Bromage, B. Bibcode: 1999JGR...104.9691G Altcode: We model electron densities of the simplest, most symmetric solar minimum streamer structure observed during the Whole Sun Month (WSM) campaign, using coronal observations of both visible white light and extreme ultraviolet (EUV) emission. Using white light data from the SOHO/LASCO/C2 and HAO/Mauna Loa Mark 3 coronagraphs, we determine electron densities by way of a Van de Hulst inversion. We compare the white light densities to those determined from the density sensitive EUV line ratios of Si IX 350/342 Å observed by the SOHO/coronal diagnostic spectrometer (CDS). Moreover, from the white light density profiles we calculate hydrostatic temperature profiles and compare to temperatures derived from the Si XII/Mg X line ratio. We find the white light and spectral analysis produce consistent density and temperature information. Title: Properties of Coronal White-Light Transients in the SPARTAN 201/WLC and SOHO/LASCO Coronagraphs Authors: Biesecker, D. A.; Kucera, T. A.; Fisher, R. R.; Gibson, S. E.; Guhathakurta, M.; Wang, D. Bibcode: 1999AAS...194.1610B Altcode: 1999BAAS...31..851B The SPARTAN 201/WLC was used to observe the solar corona from about 20:30 UT on 98/11/01 to about 13:30 UT on 98/11/03. The SOHO/LASCO coronagraphs were operating continuously throughout this period. The range of heights in the corona covered by the SPARTAN and LASCO coronagraphs and the temporal cadence of the data allow the properties of coronal transients to be examined in greater detail than previously possible with white light data. The SPARTAN coronagraph observes in white light brightness and polarized brightness at heights of 1.3 to 5.5 solar radii. The LASCO coronagraphs observe in white light brightness and polarized brightness at heights of 2.5 to 30 solar radii. We will measure the velocity and mass of the observed coronal transients with time. There were at least 4 coronal mass ejections observed with SOHO/LASCO during the time of the SPARTAN flight. Using solar disk images as a proxy, we will correct the data for plane of the sky projection. We will explore the height at which the CME's are initiated and the heights at which they are accelerated. In addition, we will determine what fraction of the mass is in a CME when it is initiated and how much is added throughout the event. Title: Physical properties of a coronal hole from a coronal diagnostic spectrometer, Mauna Loa Coronagraph, and LASCO observations during the Whole Sun Month Authors: Guhathakurta, M.; Fludra, A.; Gibson, S. E.; Biesecker, D.; Fisher, R. Bibcode: 1999JGR...104.9801G Altcode: Until recently [Guhathakurta and Fisher, 1998], inference of electron density distribution in the solar corona was limited by the field of view of white-light coronagraphs (typically out to 6 Rs). Now, for the first time we have a series of white-light coronagraphs (SOHO/LASCO) whose combined field of view extends from 1.1-30 Rs. Quantitative information on electron density distribution of coronal hole and coronal plumes/rays are estimated by using white-light, polarized brightness (pB) observations from the SOHO/LASCO/C2 and C3 and HAO/Mauna Loa Mark III coronagraphs from 1.15 to 8.0 Rs. Morphological information on the boundary of the polar coronal hole and streamer interface is determined from the white-light observations in a manner similar to the Skylab polar coronal hole boundary estimate [Guhathakurta and Holzer, 1994]. The average coronal hole electron density in the region 1-1.15 Rs is estimated from the density-sensitive EUV line ratios of Si IX 350/342 Å observed by the SOHO/coronal diagnostic spectrometer (CDS). We combine these numbers with the estimate from white-light (WL) observations to obtain a density profile from 1 to 8 Rs for the plumes and the polar coronal hole. We find that white light and spectral analysis produce consistent density information. Extrapolated densities inferred from SOHO observations are compared to Ulysses in situ observations of density. Like the density inferred from the Spartan 201-03 coronagraph, the current SOHO density profiles suggest that the acceleration of the fast solar wind takes place very close to the Sun, within 10-15 Rs. The density information is used to put constraints on solar wind flow velocities and effective temperatures. Finally, these results are compared to the recent analysis of the Spartan 201-03 white-light observations. Title: Magnetohydrodynamic modeling of the solar corona during Whole Sun Month Authors: Linker, J. A.; Mikić, Z.; Biesecker, D. A.; Forsyth, R. J.; Gibson, S. E.; Lazarus, A. J.; Lecinski, A.; Riley, P.; Szabo, A.; Thompson, B. J. Bibcode: 1999JGR...104.9809L Altcode: The Whole Sun Month campaign (August 10 to September 8, 1996) brought together a wide range of space-based and ground-based observations of the Sun and the interplanetary medium during solar minimum. The wealth of data collected provides a unique opportunity for testing coronal models. We develop a three-dimensional magnetohydrodynamic (MHD) model of the solar corona (from 1 to 30 solar radii) applicable to the WSM time period, using measurements of the photospheric magnetic field as boundary conditions for the calculation. We compare results from the computation with daily and synoptic white-light and emission images obtained from ground-based observations and the SOHO spacecraft and with solar wind measurements from the Ulysses and WIND spacecraft. The results from the MHD computation show good overall agreement with coronal and interplanetary structures, including the position and shape of the streamer belt, coronal hole boundaries, and the heliospheric current sheet. From the model, we can infer the source locations of solar wind properties measured in interplanetary space. We find that the slow solar wind typically maps back to near the coronal hole boundary, while the fast solar wind maps to regions deeper within the coronal holes. Quantitative disagreements between the MHD model and observations for individual features observed during Whole Sun Month give insights into possible improvements to the model. Title: The SPARTAN 201 White Light Coronagraph Experiment on STS-95 Authors: Fisher, R. R.; Guhathakurta, M.; Kucera, T.; Gibson, S.; Johnson, J.; Card, G.; Spartan201 Team Bibcode: 1999AAS...194.1612F Altcode: 1999BAAS...31..851F The White Light Coronagraph Experiment included in the SPARTAN 201 payload was flown on the STS-95 Space Shuttle mission which was launched on 29 October 1998. The flight systems and payload instruments were operated for a total duration of 41 hours from low earth orbit from 31 October to 2 November. The white light coronagraph experiment was designed to investigate the physical properties and the physical processes of the solar corona, and the instrument and spacecraft systems were configured for flight operations at a time of enhanced solar activity. The operational performance of the experiment and SPARTAN 201 carrier system are described, and the preliminary scientific topics of investigations are identified. Comparisons with other types of coronal data, ground-based K-coronameter and other space coronagraphs, are briefly reviewed. The data reduction plans and the scientifc goals for this mission are described. A summary of scientific insights gathered from this new data set is included in this presentation. Title: Temporal Evolution and Physical Properties of North Polar Coronal Hole from SPARTAN 201-05, SOHO, TRACE and Mk3 Authors: Guhathakurta, M.; Deforest, C.; Fisher, R. R.; Ofman, L.; Kucera, T.; Gibson, S.; Spartan201 Team Bibcode: 1999AAS...194.3203G Altcode: 1999BAAS...31..870G Polar coronal rays/plumes as long lived structures that extend out to 6 R_sun were first observed during the first flight of SPARTAN 201 spacecraft during April 11-12 of 1993. In this paper we will present detail observations from the WLC aboard Spartan 201 spacecraft (31 Oct.- 2 Nov.,1998) of the north polar coronal hole and comapre its physical properties to the past three Spartan missions. We will present comparisons of the Spartan WL observations with the Mk3 pB observations, SOHO LASCO and EIT observations, and finally the high resolution TRACE 171 Angstroms observations, to characterize the north polar coronal hole all the way from the base of the corona out to 30 R_sun. We will also look for signatures of waves (quasi-period variations) in the coronal hole plumes and interplume regions in the high cadence Spartan pB observations obtained during this mission. Title: Synoptic Sun during the first Whole Sun Month Campaign: August 10 to September 8, 1996 Authors: Biesecker, D. A.; Thompson, B. J.; Gibson, S. E.; Alexander, D.; Fludra, A.; Gopalswamy, N.; Hoeksema, J. T.; Lecinski, A.; Strachan, L. Bibcode: 1999JGR...104.9679B Altcode: A large number of synoptic maps from a variety of instruments are used to show the general morphology of the Sun at the time of the First Whole Sun Month Campaign. The campaign was conducted from August 10 to September 8, 1996. The synoptic maps cover the period from Carrington rotation 1912/253° to Carrington rotation 1913/45°. The synoptic maps encompass both on-disk data and limb data from several heights in the solar atmosphere. The maps are used to illustrate which wavelengths and data sets show particular features, such as active regions and coronal holes. Of particular interest is the equatorial coronal hole known as the ``elephant's trunk,'' which is clearly evident in the synoptic maps of on-disk data. The elephant's trunk is similar in appearance to the Skylab-era, ``Boot of Italy,'' equatorial coronal hole. The general appearance of the limb maps is explained as well. The limb maps also show evidence for equatorial coronal holes. Title: Comparison of Coronal Data between the SPARTAN 201/WLC, SOHO/LASCO, and the MARK 3 Coronagraph Authors: Kucera, T. A.; Wang, D.; Lecinski, A.; Biesecker, D. A.; Fisher, R. R.; Gibson, S. E.; Guhathakurta, M. Bibcode: 1999AAS...194.1611K Altcode: 1999BAAS...31..851K We compare coronal data from three different coronagraphs operating during the flight of SPARTAN 201-5 on Nov 1-3, 1998. The SPARTAN 201/White Light Coronagraph provides reliable data from 1.5--4.0 solar radii, bridging a gap in the radial coverage between the Mark 3 Coronagraph (which has reliable data from 1.16--1.8 solar radii) and the SOHO/LASCO C2 (2.5--6 solar radii). We will compare the radial brightness profiles of different coronal features as seen by the three different instruments, comparing the apparent structures in total white-light and polarized brightness. Title: Constraints on Coronal Outflow Velocities Derived from UVCS Doppler Dimming Measurements and in-Situ Charge State Data Authors: Strachan, L.; Ko, Y. -K.; Panasyuk, A. V.; Dobrzycka, D.; Kohl, J. L.; Romoli, M.; Noci, G.; Gibson, S. E.; Biesecker, D. A. Bibcode: 1999SSRv...87..311S Altcode: We constrain coronal outflow velocity solutions, resolved along the line-of-sight, by using Doppler dimming models of H I Lyman alpha and O VI 1032/1037 Å emissivities obtained with data from the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO. The local emissivities, from heliocentric heights of 1.5 to 3.0 solar radii, were determined from 3-D reconstructions of line-of-sight intensities obtained during the first Whole Sun Month Campaign (10 August to 8 September 1996). The models use electron densities derived from polarized brightness measurements made with the visible light coronagraphs on UVCS and LASCO, supplemented with data from Mark III at NCAR/MLSO. Electron temperature profiles are derived from 'freezing-in' temperatures obtained from an analysis of charge state data from SWICS/Ulysses. The work concentrates on neutral hydrogen outflow velocities which depend on modeling the absolute coronal H I Lyα emissivities. We use an iterative method to determine the neutral hydrogen outflow velocity with consistent values for the electron temperatures derived from a freezing-in model. Title: The Canadian Galactic plane survey. Authors: Taylor, A. R.; Gibson, S.; Leahy, D.; Peracaula, M.; Dougherty, S.; Carignan, C.; St-Louis, N.; Fich, M.; Ghazzali, N.; Joncas, G.; Pineault, S.; Mashchenko, S.; Irwin, J.; English, J.; Heiles, C.; Normandeau, M.; Martin, P.; Johnstone, D.; Basu, S.; McCutcheon, W.; Routledge, D.; Vaneldik, F.; Dewdney, P.; Galt, J.; Gray, A.; Higgs, L.; Knee, L.; Landecker, T.; Purton, C.; Roger, R. S.; Tapping, K.; Wallace, B.; Willis, T.; Beichman, C.; Duric, N.; Green, D.; Heyer, M.; Wendker, H.; Zhang, Xizhen Bibcode: 1998JRASC..92R.319T Altcode: No abstract at ADS Title: Empirical modeling of the solar corona using genetic algorithms Authors: Gibson, S. E.; Charbonneau, P. Bibcode: 1998JGR...10314511G Altcode: Many remote sensing applications encountered in astronomy and space science involve the solution of nonlinear inverse problems. These are often difficult to solve because of nonlinearities, ill-behaved integration kernels, and amplification of data noise associated with the inversion of the integral operator. In some cases these difficulties are severe enough to warrant repeated evaluations of the forward problem as an alternate approach to formal inversion. Because a forward approach is intrinsically repetitive and time consuming, an efficient and flexible forward technique is required for this avenue to be practical. We show how a forward technique based on a genetic algorithm allows us to fit magnetostatic models of the solar minimum corona to observations in white light to a degree that would otherwise have been computationally prohibitive. In addition, and perhaps equally important, the method also allows the determination of global error estimates on the model parameters defining the best fit solution. Title: Coronal Outflow Velocities in a 3D Coronal Model Determined from UVCS Doppler Dimming Observations Authors: Strachan, L.; Panasyuk, A. V.; Dobrzycka, D.; Gibson, S.; Biesecker, D. A.; Ko, Y. -K.; Galvin, A. B.; Romoli, M.; Kohn, J. L. Bibcode: 1998EOSTr..79..278S Altcode: We constrain coronal outflow velocity solutions, resolved along the line-of-sight, by using Doppler dimming models of H I Lyman alpha and O VI 1032/1037 Angstrom emissivities obtained with data from the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO. The local emissivities, from heliocentric heights of 1.5 to 3.0 radii, were determined from 3-D reconstructions of line-of-sight intensities obtained during the Whole Sun Month Campaign (10 Aug. -- 8 Sep. 1996). The models use electron densities derived from polarized brightness measurements made with the visible light coronagraphs on UVCS and LASCO, supplemented with data from Mark III at NCAR/MLSO. Electron temperature profiles are derived from `freezing-in' temperatures obtained from an analysis of charge state data from SWICS/Ulysses. The work concentrates on O5+ outflow velocities which are determined from an analysis of the the O VI line ratios. This analysis is less sensitive to the uncertainties in the electron density and independent of the ionization balance and elemental abundance than the analyses which use individual spectral lines. This work is supported in part by NASA under grant NAG-3192 to the Smithsonian Astrophysical Observatory, by the Italian Space Agency and by Swiss funding agencies. Title: Empirical Models of Temperature, Densities, and Velocities in the Solar Corona Authors: Fludra, A.; Strachan, L.; Alexander, D.; Bagenal, F.; Biesecker, D. A.; Dobrzycka, D.; Galvin, A. B.; Gibson, S.; Hassler, D.; Yo, Y. -K.; Panasyuk, A. V.; Thompson, B.; Warren, H.; del Zanna, G.; Zidowitz, S.; Antonucci, E.; Bromage, B. J. I.; Giordano, S. Bibcode: 1998EOSTr..79..278F Altcode: We present empirical results for temperatures, densities, and outflow velocities of constituents of the solar corona from 1 to 3 Ro in polar coronal holes and an equatorial streamer. Data were obtained from a variety of space and ground-based instruments during August 1996 as part of the SOHO Whole Sun Month Campaign. From white light data obtained with the SOHO/LASCO/C2 and HAO/Mauna Loa coronagraphs, we determine electron densities and compare them to those determined from the density-sensitive EUV line ratio of Si IX 350/342 Angstroms observed by the SOHO/Coronal Diagnostic Spectrometer (CDS). Moreover, from the white light density profiles we calculate temperature profiles and compare to temperature diagnostic information from EUV lines and soft X-ray images from Yohkoh. H I Ly alpha and O VI 1032/1037 Angstrom intensities from the SOHO Ultraviolet Coronagraph Spectrometer (UVCS) are used to estimate both the direction and magnitude of plasma outflow velocities in coronal holes and streamers above 1.5 Ro. The velocities are derived using densities from white light coronagraph data and coronal electron temperature estimates derived from Ulysses/SWICS ion composition data. Near the base of the corona we find the white light and spectral analysis produce consistent density and temperature information. In the extended corona we find results consistent with high outflow velocities and a superradial outflow geometry in polar coronal holes. Title: The Canadian Galactic Plane Survey. Authors: Gibson, S.; Taylor, A. R.; Leahy, A.; Dougherty, S.; Carignan, C.; St. -Louis, N.; Fich, M.; Ghazzali, N.; Joncas, G.; Pineault, S.; Normandeau, M.; Heiles, C.; Irwin, J.; English, J.; Martin, P.; Johnstone, D.; Basu, S.; McCutcheon, W.; Routledge, D.; Vaneldik, F.; Dewdney, P.; Galt, J.; Gray, A.; Higgs, L.; Knee, L.; Landecker, T.; Purton, C.; Roger, R. S.; Tapping, K.; Willis, T.; Moriarty-Schieven, G.; Beichman, C.; Terebey, S.; Duric, N.; Green, D.; Heyer, M.; Wendker, H.; Zhang, Xizhen Bibcode: 1998JRASC..92...28G Altcode: No abstract at ADS Title: A Time-Dependent Three-Dimensional Magnetohydrodynamic Model of the Coronal Mass Ejection Authors: Gibson, S. E.; Low, B. C. Bibcode: 1998ApJ...493..460G Altcode: We present a theoretical magnetohydrodynamic (MHD) model describing the time-dependent expulsion of a three-dimensional coronal mass ejection (CME) out of the solar corona. The model relates the white-light appearance of the CME to its internal magnetic field, which takes the form of a closed bubble, filled with a partly anchored, twisted magnetic flux rope, and embedded in an otherwise open background field. The model is constructed by solving in closed form the time-dependent ideal MHD equations for a γ = 4/3 polytrope making use of a similarity assumption and the application of a mathematical stretching transformation in order to treat a complex field geometry with three-dimensional variations. The density distribution frozen into the expanding CME magnetic field is obtained. The scattered white light integrated along the line of sight shows the conspicuous three features often associated with CMEs as observed with white-light coronagraphs: a surrounding high-density region, an internal low-density cavity, and a high-density core. We also show how the orientation of this three-dimensional structure relative to the line of sight can give rise to a variety of different geometric appearances in white light. These images generated from a CME model in a realistic geometry offer an opportunity to directly compare theoretical predictions on CME shapes with observations of CMEs in white light. The mathematical methods used in the model construction have general application and are described in the Appendices. Title: The ElectronTemperature Profile in the North Polar Coronal Hole During the WSM Inferred by SWICS/Ulysses,LASCO and UVCS data Authors: Ko, Y. -K.; Galvin, A. B.; Gibson, S.; Strachan, L. Bibcode: 1998EOSTr..79..283K Altcode: The solar wind ionic charge states are frozen-in in the inner solar corona within 5 solar radii. The freeze-in process, thus the frozen-in ionic charge states, depends on the electron temperature, electron density and the ion velocity in the ion's freeze-in region. Therefore the observed solar wind ionic charge states can be used to infer the physical properties in the inner solar corona where important solar wind heating and acceleration mechanisms are believed to take place. During the SOHO Whole Sun Month Campaign, Ulysses observed high speed solar wind from the north polar coronal hole. With the electron density profile derived from the LASCO/C2 and HAO/Mark 3 coronagraphs and the outflow velocities derived from the UVCS instrument, we model the electron temperature profile in the north polar coronal hole constrained by the above and the solar wind ionic charge states data observed by the SWICS instrument onboard Ulysses. Title: Self-similar Time-dependent MHD in Three-dimensional Space Authors: Low, B. C.; Gibson, S. E. Bibcode: 1997AAS...19112006L Altcode: 1997BAAS...29.1403L A general class of self-similar exact solutions to the time-dependent ideal MHD equations was discovered in the early eighties (Low 1982 ApJ 254, 796; Low 1984 ApJ 281, 392). These solutions describe exploding or imploding atmospheres in the polytropic approximation with a 4/3 index and in the presence of Newtonian gravity. A full range of accelerating, decelerating, or inertial explosions or implosions are possible. A novel feature of these solutions is that they allow for full variation in three dimensional space unstricted by any spatial symmetry, presenting an opportunity for generating models of exploding or imploding atmospheres in realistic geometry. The reduction of the problem from four dimensional space-time to the three-dimensional similarity space leads to governing equations which are still highly non-trivial to solve. This paper presents the results of a method of solution which yields a three-dimensional, analytic model of a coronal mass ejection carrying a ball of twisted magnetic fields pushing its way through surrounding open magnetic fields in a time-dependent expulsion out of the solar corona (Gibson and Low 1998 ApJ, in press). This method may be useful in other astrophysical applications. The National Center for Atmospheric Research is sponsored by the National Science Foundation. Title: Fitting a 3-D Analytic Model of the Coronal Mass Ejection to Observations Authors: Gibson, S. E.; Biesecker, D.; Fisher, R.; Howard, R. A.; Thompson, B. J. Bibcode: 1997ESASP.415..111G Altcode: 1997cpsh.conf..111G No abstract at ADS Title: Fitting a 3-d analytic model of the Coronal Mass Ejection to observations Authors: Gibson, Sarah; Fisher, Richard; Howard, Russ; Thompson, Barbara Bibcode: 1997SPD....28.0110G Altcode: 1997BAAS...29..880G We present the application of an analytic magnetohydrodynamic model (Gibson and Low, 1997) to observations of the time-dependent expulsion of three-dimensional Coronal Mass Ejections (CMEs) out of the solar corona. The model relates the white-light appearance of the CME to its internal magnetic field, which takes the form of a closed bubble, filled with a partly anchored, twisted magnetic flux rope and embedded in an otherwise open background field. The density distribution frozen into the expanding CME magnetic field is fully three-dimensional, and can be integrated along the line of sight to reproduce observations of scattered white light. The model is able to reproduce the conspicuous three features often associated with CMEs as observed with white-light coronagraphs: a surrounding high-density region, an internal low-density cavity, and a high-density core. By varying the model parameters, including the location and orientation of the CME magnetic axis relative to the limb, we are able to fit the model directly to examples of CMEs observed by the HAO/SMM Coronagraph, the HAO/Mark III K-Coronameter, and also to an event observed both by the SOHO/LASCO coronagraphs and the SOHO/EIT EUV coronal imager. Title: Results from the "Whole Sun Month" campaign Authors: Gibson, Sarah; Biesecker, Doug Bibcode: 1997SPD....28.0401G Altcode: 1997BAAS...29..907G From August 10 - September 8, 1996, a coordinated set of observations were taken as part of the "Whole Sun Month" (WSM) campaign. This campaign involved many ground- and space-based instruments (including most of those on board the SOHO satellite), and was coordinated with the IACG Campaign IV. The goal of the WSM campaign was to gather and model coronal observations of the large-scale, stable solar minimum corona, and to link these observations to in situ observations of the solar wind. The presence of a large equatorial coronal hole extension (dubbed "the elephant's trunk") during the WSM rotation facilitates the connection between coronal and in situ wind observations, as it can be directly linked to the appearance of high speed solar wind streams. We will present an overview of the observations taken, along with some of the preliminary results of collaborative modeling efforts. The purpose of the modeling is to quantify the physical properties of the 3-dimensional, large scale, stable solar minimum corona during the WSM period, between approximately 1 and 3 solar radii, and to test and use this information with models connecting the corona to in situ observations of the solar wind. Further information on the WSM campaign, the observations that have been taken, and the modeling efforts that are being planned can be found at the WSM home page at http://serts.gsfc.nasa.gov/whole_sun. Title: SOHO EIT Carrington Maps from Synoptic Full-Disk Data Authors: Thompson, B. J.; Newmark, J. S.; Gurman, J. B.; Delaboudiniere, J. P.; Clette, F.; Gibson, S. E Bibcode: 1997ESASP.404..779T Altcode: 1997cswn.conf..779T No abstract at ADS Title: A Search for the Coronal Origins of Fast Solar Wind Streams During the Whole Sun Month Period Authors: Lazarus, A. J.; Steinberg, J. T.; Biesecker, D. A.; Forsyth, R. J.; Galvin, A. B.; Ipavich, F. M.; Gibson, S. E.; Lecinski, A.; Hassler, D. M.; Hoeksema, J. T.; Riley, P.; Strachan, L., Jr.; Szabo, A.; Lepping, R. P.; Ogilvie, K. W.; Thompson, B. J. Bibcode: 1997ESASP.404..511L Altcode: 1997cswn.conf..511L No abstract at ADS Title: Polar Coronal Hole Density and its Solar Wind Consequences using LASCO Observations Authors: Guhathakurta, M.; Biesecker, D.; Gibson, S.; Fisher, R. Bibcode: 1997ESASP.404..421G Altcode: 1997cswn.conf..421G No abstract at ADS Title: Modeling a Simple Coronal Streamer during Whole Sun Month Authors: Gibson, S. E.; Bagenal, F.; Biesecker, D.; Guhathakurta, M.; Hoeksema, J. T.; Thompson, B. J. Bibcode: 1997ESASP.404..407G Altcode: 1997cswn.conf..407G No abstract at ADS Title: Applications of Genetic Algorithms to Solar Coronal Modeling Authors: Gibson, S.; Charbonneau, P. Bibcode: 1996AAS...188.3622G Altcode: 1996BAAS...28..876G Genetic algorithms are efficient and flexible means of attacking optimization problems that would otherwise be computationally prohibitive. Consider a model that represents an observable quantity in terms of a few parameters, with an associated chi (2) measuring goodness of fit with respect to data. If the modeled observable is non-linear in the parameters, there can exist a degeneracy of minimum chi (2) in parameter space. It is then essential to understand the location and extent of this degeneracy in order to find the global optimum and quantify the degeneracy error around it. Traditional methods of spanning parameter space such as a grid search or a Monte Carlo approach scale exponentially with the number of parameters, and waste a great deal of computational time looking at ``un-fit'' solutions. Genetic algorithms, on the other hand, converge rapidly onto regions of minimum chi (2) while continuously generate ``mutant solutions'', allowing an efficient and comprehensive exploration of parameter space. Our aim has been to develop an approach that simultaneously yields a best fit solution and global error estimates, by modifying and extending standard genetic algorithm-based techniques. We fit two magnetostatic models of the solar minimum corona to observations in white light. The first model allows horizontal bulk currents and the second also allows sheet currents enclosing and extending out from the equatorial helmet streamer. Using our genetic algorithm approach, we map out the degeneracy of model parameters that reproduce observations well. The flexibility of genetic algorithms facilitates incorporating the additional observational constraint of photospheric magnetic flux, reducing the degeneracy of solutions to a range represented by reasonable error bars on the model predictions. By using genetic algorithms we are able to identify and constrain the degeneracy inherent to the models, a task, which, particularly for the more complex second model, would be impractical using a traditional technique. The ultimate result is a greater understanding of the large scale structure of the solar corona, providing clues to the mechanisms heating the corona and accelerating the solar wind. Title: Current sheets in the solar minimum corona Authors: Gibson, S. E.; Bagenal, F.; Low, B. C. Bibcode: 1996JGR...101.4813G Altcode: We analytically combine stress-free current sheets with a coronal magnetostatic bulk current model. We begin by imposing a current sheet at the equator as an upper boundary condition on the modeled coronal field. We find that in order to reproduce the sharp gradients across the boundaries of helmet streamers, we also have to add current sheets along the interface between open and closed field lines. We find a description of coronal magnetic field and density in the presence of both bulk and sheet currents that matches both white light and photospheric magnetic flux observations. Title: The Large-Scale Structure of the Solar Minimum Corona Authors: Gibson, Sarah Bibcode: 1995AAS...18712204G Altcode: 1995BAAS...27R1454G I will present the results of my Ph.D. thesis, the goal of which was to find a quantitative description of the large-scale structure of magnetic field and density in the solar minimum corona that was consistent with observations of both white light intensity and the magnetic field at the photosphere. We used white light images from NASA's Solar Maximum Mission (SMM) Coronagraph/Polarimeter and the High Altitude Observatory Mark III (MkIII) K-coronameter, along with photospheric field measurements from Stanford's Wilcox Solar Observatory (WSO), as constraints on the magnetostatic model of Bogdan and Low (B&L) [\markcite{1986}]. We found a solution to the B&L model that reproduced observations of white light and photospheric flux to within quantifiable model and observational limits, and calculated the physical plasma properties of density, pressure, magnetic field, and temperature that corresponded to these parameters. Further, we extended the model to include current sheets at the equator and around the coronal helmet streamer, and showed that by doing so we improved the fit to white light data and to a lesser extent to the photospheric flux. Moreover, by including current sheets in the model, we produced a magnetic field line structure which better matched the underlying coronal white light structure, and which was more consistent with a solar wind accelerating along the open field lines. This work was partially funded by NASA GSRP grant number 50916. Title: Large-scale magnetic field and density distribution in the solar minimum corona Authors: Gibson, S. E.; Bagenal, F. Bibcode: 1995JGR...10019865G Altcode: We seek a quantitative description of the large-scale structure of magnetic field and density in the solar minimum corona that is consistent with observations of both white light intensity and the magnetic field at the photosphere. We use white light images from NASA's Solar Maximum Mission (SMM) Coronagraph/Polarimeter and the High-Altitude Observatory Mark III (MkIII) K-coronameter, along with photospheric field measurements from Stanford's Wilcox Solar Observatory (WSO), as constraints on the magnetostatic model of Bogdan and Low [1986] (B&L).

We find a family of solutions to the B&L model that reproduce observations of white light quite well, each with a different magnetic field structure. We show that the observed photospheric field cannot be used as an exact boundary condition on the B&L model, but we can limit the white light solutions by matching the total observed photospheric magnetic flux. We find a set of model parameters that reproduces white light and photospheric field to within quantifiable model and observational limits and calculate the physical plasma properties corresponding to these parameters. We conclude that this fit represents a self-consistent description of the solar minimum coronal magnetic field and density. Title: The Large-Scale Structure of the Solar Minimum Corona Authors: Gibson, Sarah Elizabeth Bibcode: 1995PhDT........21G Altcode: The goal of this thesis is to find a quantitative description of the large-scale structure of magnetic field and density in the solar minimum corona that is consistent with observations of both white light intensity and the magnetic field at the photosphere. We use white light images from NASA's Solar Maximum Mission (SMM) Coronagraph/Polarimeter and the High Altitude Observatory Mark III (MkIII) K-coronameter, along with photospheric field measurements from Stanford's Wilcox Solar Observatory (WSO), as constraints on the magnetostatic model of Bogdan and Low (B&L) (1986). We find a family of solutions to the B&L model that reproduce observations of white light quite well, each with a different magnetic field structure. We show that the observed photospheric field cannot be used as an exact boundary condition on the B&L model, but we can limit the white light solutions by matching the total observed photospheric magnetic flux. We find a set of seven model parameters that reproduces white light and photospheric field to within quantifiable model and observational limits, and calculate the physical plasma properties of density, pressure, magnetic field, and temperature that correspond to these parameters. We extend the model to include current sheets at the equator and around the coronal helmet streamer, and show that by doing so we improve the fit to white light data and to a lesser extent to the photospheric flux. Moreover, by including current sheets in the model, we produce a magnetic field line structure which better matches the underlying coronal white light structure, and which is more consistent with a solar wind accelerating along the open field lines. We use the magnetic field structure determined from our bulk current/current sheet model to calculate expansion factors, which can be used as essential inputs to solar wind models. Finally, we determine that the temperature structure predicted by our model is not in thermal equilibrium. We present a preliminary comparison of this temperature structure to independent emission line temperature diagnostics, and discuss how we hope in future to use such analyses to produce a more energetically consistent temperature distribution. Title: Large-Scale Coronal Magnetic Field and Density Structures Authors: Gibson, S.; Bagenal, F. Bibcode: 1994scs..conf..155G Altcode: 1994IAUCo.144..155G The authors have modelled the large-scale magnetic field and density structures in the corona using the magnetostatic model of Bogdan and Low (1986) and white light images from both NASA's SMM and the High Altitude Observatory Mark III. They calculated the magnetic field, density, pressure, and temperature distribution in the corona. Title: A Multi-wavelength Study of the Pleiades Region in Conjunction with WISP Authors: Gibson, S.; Nordsieck, K. H.; Afflerbach, A.; Anderson, C. M.; Jaehnig, K. P.; Michalski, P. E. Bibcode: 1994ASPC...58...78G Altcode: 1994icdi.conf...78G No abstract at ADS Title: The Large Scale Structure of the Solar Corona Authors: Gibson, S.; Bagenal, F. Bibcode: 1993BAAS...25.1211G Altcode: No abstract at ADS Title: Modelling the large scale structure of the solar corona. Authors: Gibson, Sarah; Bagenal, F. Bibcode: 1992ESASP.348..101G Altcode: 1992cscl.work..101G The authors find a quantitative description of the large scale structure of magnetic field and density distribution in the coronal plasma. They use the magnetostatic model of Bogdan and Low and white light images from both NASA's SMM Coronagraph/Polarimeter and the High Altitude Observatory Mark III K-coronameter. By combining the SMM and MkIII datasets the authors were able to more accurately determine a density distribution that matched the white light images of the corona. The model then allows to calculate the magnetic field and plasma characteristics (such as the coronal temperature structure) which are essential for understanding the mechanisms that heat the corona and drive the solar wind. Title: Modelling the Large Scale Structure of the Solar Corona Authors: Gibson, S.; Bagenal, F. Bibcode: 1992AAS...180.1207G Altcode: 1992BAAS...24..748G We report on recent attempts to find a quantitative description of both the magnetic field and the distribution of plasma in the lower corona that matches the white light images of the K-corona. We use the magnetostatic model of Bogdan and Low and data obtained by the High Altitude Observatory K-Coronameter (1.2 - 2.3 Rsun) and the Solar Maximum Mission Coronameter/Polarimeter (1.5 - 4 Rsun). By varying parameters in the Bogdan and Low model we are able to quantitatively match the general characteristics of the lower corona at solar minimum: power law radial profiles of coronal brightness: enhanced brightness at the equator; uniform density depletion at the pole. Further, we use the best fit model to determine a temperature distribution in the corona and investigate the implications this has for solar wind theory. Title: Modeling the large-scale structure of the solar corona Authors: Bagenal, F.; Gibson, S. Bibcode: 1992sws..coll..135B Altcode: The aim of this study is to find a quantitative description of both the magnetic field and the distribution of plasma in the lower corona that matches the white light images of the K-corona. We use the magnetostatic model of Bogdan and Low (1986) and data obtained by the High Altitude Observatory Mark III K-Coronameter stationed at Mauna Loa, Hawaii. To start with, we take the simplest, solar minimum case when the corona is approximately longitudinally symmetric. By varying parameters in the Bogdan and Low model we are able to quantitatively match the general characteristics of the lower corona at solar minimum: power law radial profiles of coronal brightness; enhanced brightness at the equator; uniform density depletion at the pole. Title: Modeling the large-scale structure of the solar corona Authors: Bagenal, F.; Gibson, S. Bibcode: 1991JGR....9617663B Altcode: The aim of this study is to find a quantitative description of both the magnetic field and the distribution of plasma in the lower corona that matches the white light images of the K-corona. We use the magnetostatic model of Bogdan and Low (1986) and data obtained by the High Altitude Observatory Mark III K-Coronameter stationed at Mauna Loa, Hawaii. To start with, we take the simplest, solar minimum case when the corona is approximately longitudinally symmetric. By varying parameters in the Bogdan and Low model we are able to quantitatively match the general characteristics of the lower corona at solar minimum: power law radial profiles of coronal brightness; enhanced brightness at the equator; uniform density depletion at the pole. Further, we find the set of parameters that best fit the data and investigate how well the model parameters are resolved by the data. Title: Modelling the Large-Scale Structure of the Corona Authors: Bagenal, F.; Gibson, S. Bibcode: 1991BAAS...23.1058B Altcode: No abstract at ADS Title: Modeling the Solar Corona at Solar Minimum Authors: Bagenal, F.; Gibson, S. Bibcode: 1990BAAS...22..869B Altcode: No abstract at ADS