Author name code: frank ADS astronomy entries on 2022-09-14 author:"Frank, Zoe" ------------------------------------------------------------------------ Title: Changes in granulation scales over the solar cycle seen with SDO/HMI and Hinode/SOT Authors: Ballot, J.; Roudier, T.; Malherbe, J. M.; Frank, Z. Bibcode: 2021A&A...652A.103B Altcode: 2021arXiv210603556B Context. The Sun is the only star where the superficial turbulent convection can be observed at very high spatial resolution. The Solar Dynamics Observatory (SDO) has continuously observed the full Sun from space with multi-wavelength filters since July 2010. In particular, the Helioseismic and Magnetic Imager (HMI) instrument takes high-cadence frames (45 s) of continuum intensity in which solar granulation is visible.
Aims: We aimed to follow the evolution of the solar granules over an activity cycle and look for changes in their spatial properties.
Methods: We investigated the density of granules and their mean area derived directly from the segmentation of deconvolved images from SDO/HMI. To perform the segmentation, we define granules as convex elements of images.
Results: We measured an approximately 2% variation in the density and the mean area of granules over the cycle, the density of granules being greater at solar maximum with a smaller granule mean area. The maximum density appears to be delayed by about one year compared to classical activity indicators, such as the sunspot number. We complemented this study with high-spatial-resolution observations obtained with Hinode/SOTBFI (Solar Optical Telescope Broadband Filter Imager), which are consistent with our results.
Conclusions: The observed variations in solar granulation at the disc centre reveal a direct insight into the change in the physical properties that occur in the upper convective zone during a solar cycle. These variations can be due to interactions between convection and magnetic fields, either at the global scale or, locally, at the granulation scale. Title: mschauer/BridgeLandmarks.jl: v0.4.0 Authors: Frank; Schauer, Moritz Bibcode: 2021zndo...5101751F Altcode: BridgeLandmarks v0.4.0 Diff since v0.3.1 Closed issues: Registration (#19) Merged pull requests: CompatHelper: bump compat for "Plots" to "1.0" (#24) (@github-actions[bot]) CompatHelper: bump compat for "GaussianDistributions" to "0.4" (#25) (@github-actions[bot]) CompatHelper: bump compat for "DataFrames" to "0.21" (#28) (@github-actions[bot]) CompatHelper: add new compat entry for "StatsFuns" at version "0.9" (#38) (@github-actions[bot]) CompatHelper: bump compat for "JLD2" to "0.3" (#41) (@github-actions[bot]) CompatHelper: bump compat for "DataFrames" to "0.22" (#42) (@github-actions[bot]) MassInstallAction: Install the Documenter workflow on this repository (#44) (@mschauer) MassInstallAction: Install the CI workflow on this repository (#45) (@mschauer) CompatHelper: bump compat for "DataFrames" to "1.0" (#49) (@github-actions[bot]) CompatHelper: bump compat for "Distributions" to "0.25" (#50) (@github-actions[bot]) CompatHelper: bump compat for "StaticArrays" to "1.2" (#51) (@github-actions[bot]) finalchanges (#52) (@fmeulen) new version nr (#53) (@fmeulen) change version bounds (#54) (@fmeulen) Title: mschauer/Bridge.jl: v0.11.6 Authors: Schauer, Moritz; Frank; getzdan; Bezanson, Jeff; Corstanje, Marc; Piibeleht, Morten; Simon; Kelman, Tony Bibcode: 2021zndo....891230S Altcode: 2019zndo....891230S Bridge v0.11.6 Diff since v0.11.5 Closed issues: Release 0.11.* (#65) Merged pull requests: CompatHelper: bump compat for "StaticArrays" to "1.0" (#84) (@github-actions[bot]) CompatHelper: bump compat for "SpecialFunctions" to "1.2" (#86) (@github-actions[bot]) CompatHelper: bump compat for "Polynomials" to "2.0" (#87) (@github-actions[bot]) CompatHelper: bump compat for "StaticArrays" to "1.1" (#88) (@github-actions[bot]) Title: Photospheric downflows observed with SDO/HMI, HINODE, and an MHD simulation Authors: Roudier, T.; Švanda, M.; Malherbe, J. M.; Ballot, J.; Korda, D.; Frank, Z. Bibcode: 2021A&A...647A.178R Altcode: 2021arXiv210303077R Downflows on the solar surface are suspected to play a major role in the dynamics of the convection zone, at least in its outer part. We investigate the existence of the long-lasting downflows whose effects influence the interior of the Sun but also the outer layers. We study the sets of Dopplergrams and magnetograms observed with Solar Dynamics Observatory and Hinode spacecrafts and an magnetohydrodynamic (MHD) simulation. All of the aligned sequences, which were corrected from the satellite motions and tracked with the differential rotation, were used to detect the long-lasting downflows in the quiet-Sun at the disc centre. To learn about the structure of the flows below the solar surface, the time-distance local helioseismology was used. The inspection of the 3D data cube (x, y, t) of the 24 h Doppler sequence allowed us to detect 13 persistent downflows. Their lifetimes lie in the range between 3.5 and 20 h with a sizes between 2″ and 3″ and speeds between −0.25 and −0.72 km s−1. These persistent downflows are always filled with the magnetic field with an amplitude of up to 600 Gauss. The helioseismic inversion allows us to describe the persistent downflows and compare them to the other (non-persistent) downflows in the field of view. The persistent downflows seem to penetrate much deeper and, in the case of a well-formed vortex, the vorticity keeps its integrity to the depth of about 5 Mm. In the MHD simulation, only sub-arcsecond downflows are detected with no evidence of a vortex comparable in size to observations at the surface of the Sun. The long temporal sequences from the space-borne allows us to show the existence of long-persistent downflows together with the magnetic field. They penetrate inside the Sun but are also connected with the anchoring of coronal loops in the photosphere, indicating a link between downflows and the coronal activity. A links suggests that EUV cyclones over the quiet Sun could be an effective way to heat the corona. Title: python-visualization/folium v0.12.1 Authors: Filipe; Journois, Martin; Frank; Story, Rob; Gardiner, James; Rump, Halfdan; Bird, Andrew; Lima, Antonio; Cano, Joshua; Dbf; Leonel, Juliana; Baker, Jason; Sampson, Tim; Reades, Jon; Welsh, Ben; Kong, Qingkai; Komarov, Oleg; Crosby, Alex; Harris, George; Dumas, Raphael; KRIEF, David; Kato, Daisuke; Penguindustin; Wilson, Nat; Paiva Nogueira, Tales; Kenmatsu4; Furtado, Leonardo; Patil, Anand; Duke, Justin; Signell, Rich Bibcode: 2021zndo...4447642F Altcode: Minor bugfix on the version number in the source distribution Title: Search Tool for Retrieving Level 2 Data from Hinode's Spectro-Polarimeter (SP) Authors: Kam, C.; Arbolante, Q.; Frank, Z.; DeRosa, M. L. Bibcode: 2020AGUFMED0260056K Altcode: A joint project between JAXA and NASA, the Hinode Solar Optical Telescope (SOT) has observed our Sun since its launch in October 2006. Mission data has been used extensively to study solar flares, polar magnetic fields, prominence structures, and changes over the solar cycle. Archived databases of the SOT filtergraph (FG) images and spectropolarimeter (SP) maps are maintained in the US, Japan, and Norway. Many tools for accessing SOT data were developed early in the mission timeline and are based on Harris Geospatial Solutions Inc. Interactive Data Language (IDL). We demonstrate a new open source Python-based search and cross referencing tool for the Hinode SOT SP. This tool maps their associated Level 2 inversion data products from the Heliophysics Events Knowlegebase (HEK) and enables greater accessibility to this ongoing international mission. Title: Evolution of exploding granules from coordinated observations by THEMIS, IRIS, SDO/HMI, and HINODE, and a simulation Authors: Roudier, T.; Malherbe, J. M.; Gelly, B.; Douet, R.; Frank, Z.; Dalmasse, K. Bibcode: 2020A&A...641A..50R Altcode: 2020arXiv200712438R Exploding granules constitute the strongest horizontal flows on the quiet Sun and contribute to the structure of the surface horizontal velocity fields which build the large-scale organization of the discrete magnetic field. In this work we explore exploding granule expansion through the observations of the ground-based THEMIS telescope, IRIS, SDO, and the Hinode space-borne instruments, and finally with the magnetohydrodynamics simulation. We evaluate the detection and the expansion of exploding granules at several wavelengths and at various spatial and temporal resolutions. To analyze the different temporal sequences, two methods of image segmentation are applied to select the granules. The first allows us to follow individually the exploding granules observed simultaneously by THEMIS, IRIS, and SDO. The second uses long time independent sequences from THEMIS, IRIS, SDO, Hinode, and a simulation. In the first method (called manual) the segmentation isolates the cell of the granules (bright granules and intergranular parts), while in the second method (called statistical) only the bright part of the granules are isolated. The results obtained with simultaneous or distinct temporal observations using the two methods of segmentation are in good agreement. The granule area evolves linearly with an expansion velocity that decreases with the radius. A rapid decrease in the velocity expansion in the first two minutes is observed. The detection and measurement of the dynamics of the explosive granules can be performed from ground- and space-based instruments. Our work reveals the usefulness of SDO data, with low spatial resolution, to study the dynamics of the exploding granules all over the solar surface. Title: mschauer/BridgeLandmarks.jl: v0.3.0 Authors: Schauer, Moritz; Frank Bibcode: 2020zndo...3634591S Altcode: A changelog is being generated, please check back in a few minutes. Title: Link between trees of fragmenting granules and deep downflows in MHD simulation Authors: Roudier, T.; Malherbe, J. M.; Stein, R. F.; Frank, Z. Bibcode: 2019A&A...622A.112R Altcode: 2019arXiv190103255R Context. Trees of fragmenting granules (TFG) and associated flows are suspected to play a major role in the formation of the network in the quiet Sun. We investigate the counterparts, in terms of dynamics, of surface structures detectable by high resolution observations in deeper layers up to 15 Mm, which are only available from numerical simulations.
Aims: The first aim is to demonstrate that TFG can be evidenced either from surface intensitites, vertical (Vz), or Doppler (Vdop) velocities. The second is to show that horizontal flows, which are derived from intensities or Vz/Vdop flows, are in good agreement, and that this is the case for observations and numerical simulations. The third objective is to apply this new Vz-based method to a 3D simulation to probe relationships between horizontal surface flows, TFG, and deep vertical motions.
Methods: The TFG were detected after oscillation filtering of intensities or Vz/Vdop flows, using a segmentation and labelling technique. Surface horizontal flows were derived from local correlation tracking (LCT) and from intensities or Vz/Vdop flows. These methods were applied to Hinode observations, 2D surface results of a first simulation, and 3D Vz data of a second simulation.
Results: We find that TFG and horizontal surface flows (provided by the LCT) can be detected either from intensities or Vz/Vdop component, for high resolution observations and numerical simulations. We apply this method to a 3D run providing the Vz component in depth. This reveals a close relationship between surface TFG (5 Mm mesoscale) and vertical downflows 5 Mm below the surface. We suggest that the dynamics of TFG form larger scales (the 15-20 Mm supergranulation) associated with 15 Mm downflowing cells below the surface.
Conclusions: The TFG and associated surface flows seem to be essential to understanding the formation and evolution of the network at the meso and supergranular scale.

Movies associated to Figs. 3, 11, 12, and 14 are availabe at https://www.aanda.org Title: roced-scheduler/ROCED 1.1.0 Authors: GuentherErli; mschnepf; Frank; Hauth, Thomas; GeorgFleig Bibcode: 2018zndo...1888310G Altcode: ROCED cloud scheduler Title: Dynamics of Trees of Fragmenting Granules in the Quiet Sun: Hinode/SOT Observations Compared to Numerical Simulation Authors: Malherbe, J. -M.; Roudier, T.; Stein, R.; Frank, Z. Bibcode: 2018SoPh..293....4M Altcode: 2018arXiv180401870M We compare horizontal velocities, vertical magnetic fields, and the evolution of trees of fragmenting granules (TFG, also named families of granules) derived in the quiet Sun at disk center from observations at solar minimum and maximum of the Solar Optical Telescope (SOT on board Hinode) and results of a recent 3D numerical simulation of the magneto-convection. We used 24-hour sequences of a 2D field of view (FOV) with high spatial and temporal resolution recorded by the SOT Broad band Filter Imager (BFI) and Narrow band Filter Imager (NFI). TFG were evidenced by segmentation and labeling of continuum intensities. Horizontal velocities were obtained from local correlation tracking (LCT) of proper motions of granules. Stokes V provided a proxy of the line-of-sight magnetic field (BLOS). The MHD simulation (performed independently) produced granulation intensities, velocity, and magnetic field vectors. We discovered that TFG also form in the simulation and show that it is able to reproduce the main properties of solar TFG: lifetime and size, associated horizontal motions, corks, and diffusive index are close to observations. The largest (but not numerous) families are related in both cases to the strongest flows and could play a major role in supergranule and magnetic network formation. We found that observations do not reveal any significant variation in TFG between solar minimum and maximum. Title: Comparing Dynamics in Eruptive and Non-Eruptive Flares Authors: Nitta, Nariaki; Tarbell, Theodore D.; Slater, Gregory L.; Frank, Zoe Anne Bibcode: 2016SPD....47.0620N Altcode: Close comparison of EUV and coronagraph data suggests that there may not be clear distinction between eruptive and non-eruptive flares as far as the coronal and chromospheric signatures are concerned. Here we define eruptive and non-eruptive flares in terms of the presence and absence of the associated coronal mass ejection (CME). We have studied several flares in both categories using Hinode/SOT and IRIS data. The pointing of the Hinode/SOT data has been updated by correlating them with AIA 1700 A images. We show our initial results about how the flare development compares in eruptive and non-eruptive flares, including the reconnection rate as derived from the magnetic field swept over by flare ribbons (in SOT Ca images), and the line-of-sight velocities at different locations and temperatures (in IRIS spectral data). We also discuss large-scale disturbances and related CMEs in SDO/AIA and SOHO/LASCO data as context information. Title: Relation between trees of fragmenting granules and supergranulation evolution Authors: Roudier, Th.; Malherbe, J. M.; Rieutord, M.; Frank, Z. Bibcode: 2016A&A...590A.121R Altcode: 2016arXiv160404118R Context. The determination of the underlying mechanisms of the magnetic elements diffusion over the solar surface is still a challenge. Understanding the formation and evolution of the solar network (NE) is a challenge, because it provides a magnetic flux over the solar surface comparable to the flux of active regions at solar maximum.
Aims: We investigate the structure and evolution of interior cells of solar supergranulation. From Hinode observations, we explore the motions on solar surface at high spatial and temporal resolution. We derive the main organization of the flows inside supergranules and their effect on the magnetic elements.
Methods: To probe the superganule interior cell, we used the trees of fragmenting granules (TFG) evolution and their relations to horizontal flows.
Results: Evolution of TFG and their mutual interactions result in cumulative effects able to build horizontal coherent flows with longer lifetime than granulation (1 to 2 h) over a scale up to 12''. These flows clearly act on the diffusion of the intranetwork (IN) magnetic elements and also on the location and shape of the network.
Conclusions: From our analysis during 24 h, TFG appear as one of the major elements of the supergranules which diffuse and advect the magnetic field on the Sun's surface. The strongest supergranules contribute the most to magnetic flux diffusion in the solar photosphere.

Movies are available in electronic form at http://www.aanda.org Title: Families of Granules, Flows, and Acoustic Events in the Solar Atmosphere from Hinode Observations Authors: Malherbe, J. -M.; Roudier, T.; Frank, Z.; Rieutord, M. Bibcode: 2015SoPh..290..321M Altcode: 2014SoPh..tmp..189M We investigate the relationship between trees of fragmenting granules (TFG), horizontal and vertical flows, and acoustic events (AE) in the photospheric network. AE are spatially concentrated and short-duration locations of acoustic energy flux. We performed observations at disk center of a 2D field of view (FOV) with high spatial and temporal resolutions provided by the Solar Optical Telescope onboard Hinode. Line profiles of Fe I 557.6 nm were recorded by the Narrow-band Filter Imager on an 80″×36″ FOV during five hours with a cadence of 22 seconds and 0.08″ pixel size. Vertical velocities were derived at two atmospheric levels allowing the determination of the energy flux at the acoustic frequency of 3.3 mHz. Families of granules and horizontal velocities were obtained from local correlation tracking (LCT) after segmentation and labeling of either continuum intensities or granular Doppler shifts. AE exhibit durations in the range 0.25 to 1 hour compatible with the lifetime of families (80 % do not last more than two hours). High-energy AE have the shortest lifetimes. We found that most AE occur in intergranular lanes located in or close to the boundaries between different families (called inter families) in regions with predominantly downward vertical motions and horizontal converging flows. In contrast, diverging flows are observed inside families, with a few AE in the intergranules. At the beginning of the sequence, when families are not yet detected, the distribution of AE is not uniform and is already organized at spatial lengths related to the mesogranular scale, with maximum contribution in the range 5″ to 10″, fully compatible with the scale of the maximum contribution of families in the TFG space. Although all sizes and durations seem to exist for families, their number decreases with increasing size and lifetime. Title: Comparison of solar horizontal velocity fields from SDO/HMI and Hinode data Authors: Roudier, Th.; Rieutord, M.; Prat, V.; Malherbe, J. M.; Renon, N.; Frank, Z.; Švanda, M.; Berger, T.; Burston, R.; Gizon, L. Bibcode: 2013A&A...552A.113R Altcode: 2013arXiv1303.4271R Context. The measurement of the Sun's surface motions with a high spatial and temporal resolution is still a challenge.
Aims: We wish to validate horizontal velocity measurements all over the visible disk of the Sun from Solar Dynamics Observatory/ Helioseismic and Magnetic Imager (SDO/HMI) data.
Methods: Horizontal velocity fields are measured by following the proper motions of solar granules using a newly developed version of the coherent structure tracking (CST) code. The comparison of the surface flows measured at high spatial resolution (Hinode, 0.1 arcsec) and low resolution (SDO/HMI, 0.5 arcsec) allows us to determine corrections to be applied to the horizontal velocity measured from HMI white light data.
Results: We derive horizontal velocity maps with spatial and temporal resolutions of respectively 2.5 Mm and 30 min. From the two components of the horizontal velocity vx and vy measured in the sky plane and the simultaneous line of sight component from SDO/HMI dopplergrams vD, we derive the spherical velocity components (vr, vθ, vϕ). The azimuthal component vϕ gives the solar differential rotation with a high precision (± 0.037 km s-1) from a temporal sequence of only three hours.
Conclusions: By following the proper motions of the solar granules, we can revisit the dynamics of the solar surface at high spatial and temporal resolutions from hours to months and years with the SDO data. Title: Plasma Instabilities in Quiescent Prominences Authors: Ryutova, M.; Berger, T.; Frank, Z.; Title, A.; Tarbell, T. Bibcode: 2012ASPC..454..143R Altcode: We study dynamics of quiescent prominences using several data sets taken with the SOT on Hinode. We find a number of processes occurring at different stages of the prominence evolution that are common for all the chosen cases, and having universal character, can be related to a fundamental plasma instabilities. We combine the observational evidence and theory to identify these instabilities. Here we discuss only two examples: (1) Coronal cavity formation under a prominence body and its evolution associated with screw pinch instability, and (2) Development of a regular series of plumes and spikes typical to the Rayleigh-Taylor instability modified by solenoidal magnetic field. Title: The Power Spectrum of the Solar Surface Flows from Hinode Data and First Observations with MOF/CALAS Pic-du-Midi Authors: Roudier, T.; Rieutord, M.; Rincon, F.; Malherbe, J. -M.; Brito, D.; Berger, T.; Frank, Z.; Parés, L.; Bourrec, E.; Beigbeder, F. Bibcode: 2012ASPC..454...47R Altcode: Many features of solar surface turbulence, like the supergranulation, are still poorly understood.We use long time series of images taken by the Solar Optical Telescope on board the Hinode satellite to determine the velocity fields. The dynamics in the subgranulation range can be investigated with unprecedented precision thanks to the absence of seeing effects and the use of the MTF of SOT for correcting the spectra. The first MOF/CALAS/Pic-du-Midi results are also shown. Title: Some Dynamic Analysis of the Photosphere from Hinode/SOT and SDO/HMI Observations Authors: Roudier, T.; Malherbe, J.; Rieutord, M.; Berger, T.; Frank, Z.; Prat, V.; Renon, N.; Gizon, L.; Svanda, M. Bibcode: 2012ASPC..456...65R Altcode: We first present the important role played by the families of granule (or Tree of Fragmenting granules) in the formation of the photospheric network. Then, we describe the occurence and characteristics of acoustic events (AE), defined as spatially concentrated energy flux, in the quiet Sun. Finally, we present how horizontal velocities obtained from SDO/HMI data are calibrated by using Hinode/SOT observations. Title: Quasi full-disk maps of solar horizontal velocities using SDO/HMI data Authors: Roudier, Th.; Rieutord, M.; Malherbe, J. M.; Renon, N.; Berger, T.; Frank, Z.; Prat, V.; Gizon, L.; Švanda, M. Bibcode: 2012A&A...540A..88R Altcode: 2012arXiv1203.0514R
Aims: For the first time, the motion of granules (solar plasma on the surface on scales larger than 2.5 Mm) has been followed over the entire visible surface of the Sun, using SDO/HMI white-light data.
Methods: Horizontal velocity fields are derived from image correlation tracking using a new version of the coherent structure tracking algorithm. The spatial and temporal resolutions of the horizontal velocity map are 2.5 Mm and 30 min, respectively.
Results: From this reconstruction, using the multi-resolution analysis, one can obtain to the velocity field at different scales with its derivatives such as the horizontal divergence or the vertical component of the vorticity. The intrinsic error on the velocity is ~0.25 km s-1 for a time sequence of 30 min and a mesh size of 2.5 Mm. This is acceptable compared to the granule velocities, which range between 0.3 km s-1 and 1.8 km s-1. A high correlation between velocities computed from Hinode and SDO/HMI has been found (85%). From the data we derive the power spectrum of the supergranulation horizontal velocity field, the solar differential rotation, and the meridional velocity. Title: Flares Producing Well-organized Post-flare Arcades (Slinkies) Have Early Precursors Authors: Ryutova, M. P.; Frank, Z.; Hagenaar, H.; Berger, T. Bibcode: 2011ApJ...733..125R Altcode: Exploding loop systems producing X-ray flares often, but not always, bifurcate into a long-living, well-organized system of multi-threaded loop arcades resembling solenoidal slinkies. The physical conditions that cause or prevent this process are not known. To address this problem, we examined most of the major (X-class) flares that occurred during the last decade and found that the flares that bifurcate into long-living slinky arcades have different signatures than those that do not "produce" such structures. The most striking difference is that, in all cases of slinky formation, GOES high energy proton flux becomes significantly enhanced 10-24 hr before the flare occurs. No such effect was found prior to the "non-slinky" flares. This fact may be associated with the difference between energy production by a given active region and the amount of energy required to bring the entire system into the form of well-organized, self-similar loop arcades. As an example illustrating the process of post-flare slinky formation, we present observations taken with the Hinode satellite, in several wavelengths, showing a time sequence of pre-flare and flare activity, followed by the formation of dynamically stable, well-organized structures. One of the important features revealed is that post-flare coronal slinky formation is preceded by scale invariant structure formation in the underlying chromosphere/transition region. We suggest that the observed regularities can be understood within the framework of self-organized critical dynamics characterized by scale invariant structure formation with critical parameters largely determined by energy saturation level. The observed regularities per se may serve as a long-term precursor of strong flares and may help to study predictability of system behavior. Title: Observation of Plasma Instabilities in Quiescent Prominences Authors: Ryutova, M.; Berger, T.; Frank, Z.; Tarbell, T.; Title, A. Bibcode: 2010SoPh..267...75R Altcode: 2010SoPh..tmp..170R We study dynamics of quiescent prominences using several data sets taken with the Solar Optical Telescope (SOT) on Hinode. We find a number of processes occurring at different stages of prominence evolution that are common for all of our chosen cases and, having universal character, can be related to fundamental plasma instabilities. We combine the observational evidence and theory to identify these instabilities. Here we discuss three examples: i) prominence cavity formation and its evolution, associated with a screw-pinch instability; ii) development of a regular series of plumes and spikes typical to the Rayleigh - Taylor (RT) instability; and iii) the appearance of growing ripples at the prominence/corona interface, often followed by a sudden collimated mass upflow, attributed to the Kelvin - Helmholtz (KH) instability. The conditions for transition from a linear (rippling mode) to nonlinear stage of the KH instability, known to have an explosive character, are specified. Given excellent Hinode data, all three aspects of prominence dynamics allow quantitative analysis. Title: Sharing new data from Solar Dynamics Observatory Authors: Friedman, Benji; Zita, E. J.; Frank, Zoe Bibcode: 2010APS..NWS.D1004F Altcode: New data from the Solar Dynamics Observatory (SDO) provides opportunities to share exciting information about the Sun with people outside the field of science. This presents the challenge of how best to communicate important findings to an audience that may not know the astrophysical vernacular to understand what's going on. This summer, I worked on various methods, including Facebook and Lockheed Martin's Picture of the Day website, to inform the public about the Sun, that mysterious star on which we rely. I will describe methods for finding interesting new solar events, making pictures and movies of solar dynamics, and uploading and annotating them for the public. Title: Emergence of Helical Flux and the Formation of an Active Region Filament Channel Authors: Lites, B. W.; Kubo, M.; Berger, T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Okamoto, T. J.; Otsuji, K. Bibcode: 2010ApJ...718..474L Altcode: We present comprehensive observations of the formation and evolution of a filament channel within NOAA Active Region (AR) 10978 from Hinode/Solar Optical Telescope and TRACE. We employ sequences of Hinode spectro-polarimeter maps of the AR, accompanying Hinode Narrowband Filter Instrument magnetograms in the Na I D1 line, Hinode Broadband Filter Instrument filtergrams in the Ca II H line and G-band, Hinode X-ray telescope X-ray images, and TRACE Fe IX 171 Å image sequences. The development of the channel resembles qualitatively that presented by Okamoto et al. in that many indicators point to the emergence of a pre-existing sub-surface magnetic flux rope. The consolidation of the filament channel into a coherent structure takes place rapidly during the course of a few hours, and the filament form then gradually shrinks in width over the following two days. Particular to this filament channel is the observation of a segment along its length of horizontal, weak (500 G) flux that, unlike the rest of the filament channel, is not immediately flanked by strong vertical plage fields of opposite polarity on each side of the filament. Because this isolated horizontal field is observed in photospheric lines, we infer that it is unlikely that the channel formed as a result of reconnection in the corona, but the low values of inferred magnetic fill fraction along the entire length of the filament channel suggest that the bulk of the field resides somewhat above the low photosphere. Correlation tracking of granulation in the G band presents no evidence for either systematic flows toward the channel or systematic shear flows along it. The absence of these flows, along with other indications of these data from multiple sources, reinforces (but does not conclusively demonstrate) the picture of an emerging flux rope as the origin of this AR filament channel. Title: On the power spectrum of solar surface flows Authors: Rieutord, M.; Roudier, T.; Rincon, F.; Malherbe, J. -M.; Meunier, N.; Berger, T.; Frank, Z. Bibcode: 2010A&A...512A...4R Altcode: 2009arXiv0911.3319R Context. The surface of the Sun provides us with a unique and very detailed view of turbulent stellar convection. Studying its dynamics can therefore help us make significant progress in stellar convection modelling. Many features of solar surface turbulence like the supergranulation are still poorly understood.
Aims: The aim of this work is to give new observational constraints on these flows by determining the horizontal scale dependence of the velocity and intensity fields, as represented by their power spectra, and to offer some theoretical guidelines to interpret these spectra.
Methods: We use long time-series of images taken by the Solar Optical Telescope (SOT) on board the Hinode satellite; we reconstruct both horizontal (by granule tracking) and vertical (by Doppler effect) velocity fields in a field-of-view of ~ 75 × 75 Mm2. The dynamics in the subgranulation range can be investigated with unprecedented precision thanks to the absence of seeing effects and the use of the modulation transfer function of SOT for correcting the spectra.
Results: At small subgranulation scales down to 0.4 Mm the spectral density of kinetic energy associated with vertical motions exhibits a k-10/3-like power law, while the intensity fluctuation spectrum follows either a k-17/3 or a k-3-like power law at the two continuum levels investigated (525 and 450 nm respectively). We discuss the possible physical origin of these scalings and interpret the combined presence of k-17/3 and k-10/3 power laws for the intensity and vertical velocity as a signature of buoyancy-driven turbulent dynamics in a strongly thermally diffusive regime. In the mesogranulation range and up to a scale of 25 Mm, we find that the amplitude of the vertical velocity field decreases like λ-3/2 with the horizontal scale λ. This behaviour corresponds to a k2 spectral power law. Still in the 2.5-10 Mm mesoscale range, we find that intensity fluctuations in the blue continuum also follow a k2 power law. In passing we show that granule tracking cannot sample scales below 2.5 Mm. We finally further confirm the presence of a significant supergranulation energy peak at 30 Mm in the horizontal velocity power spectrum and show that the emergence of a pore erases this spectral peak. We tentatively estimate the scale height of the vertical velocity field in the supergranulation range and find 1 Mm; this value suggests that supergranulation flows are shallow. Title: Joint STEREO-Hinode Observations of Coronal Dimming and Waves Associated with a CME/Flare Event Authors: Nitta, Nariaki; Aschwanden, Markus; Frank, Zoe; Slater, Gregory; Tarbell, Theodore; Zarro, Dominic Bibcode: 2010cosp...38.2928N Altcode: 2010cosp.meet.2928N During the solar minimum between cycles 23 and 24, a number of minor flares from unimpressive active regions were associated with large-scale dimming and waves as observed by the EUV Imager (EUVI) on STEREO. We present a detailed study on one of the CME/flare events that was observed also by the instruments on Hinode. We analyze SOT Ca II data to explore the origin of the disturbances and EIS slit spectra to determine the timings of the upflow and associated turbulence that are presumably correlated with coronal dimming. The sequence of phenomena as captured by different instruments on STEREO, Hinode and SOHO helps us identify the key physical processes that gave rise to the event. Title: Response of the Chromosphere to Penumbral Dynamics: Bow Shocks and Microjets Authors: Ryutova, M.; Berger, T.; Frank, Z.; Title, A. Bibcode: 2009ASPC..415..373R Altcode: We have analyzed the data sets obtained with the SOT instrument on Hinode during the disc passage of AR 10923 (November 10--20, 2006). Along with a limited number of jet-like features (Katsukawa 2007), we found other kinds of bright chromospheric transients abundantly pervading the entire penumbra and drifting as a whole in a direction perpendicular to their long axes. Quantitative analysis based on our recent penumbral model (Ryutova et al. 2008a) shows that they have all the signatures of bow shocks produced in the overlying chromosphere by post-reconnection penumbral filaments. Title: Supergranulation, Network Formation, and TFGs Evolution from Hinode Observations Authors: Roudier, T.; Rincon, F.; Rieutord, M.; Brito, D.; Beigbeder, F.; Parès, L.; Malherbe, J. -M.; Meunier, N.; Berger, T.; Frank, Z. Bibcode: 2009ASPC..415..203R Altcode: In this paper, we analyse a a 48h high-resolution time sequence of the quiet Sun photosphere obtained with the Solar Optical Telescope onboard Hinode. Using floating corks advected by velocity fields inferred from photometry measurements, we show that long-living Trees of Fragmenting Granules play a crucial role in the advection of small-scale magnetic fields and in the build-up of the magnetic network. Title: Formation and Dynamics of Multi-thread Arcades of Coronal Loops Authors: Ryutova, M.; Frank, Z.; Berger, T. Bibcode: 2009ASPC..415..291R Altcode: Coronal structures having various forms and dynamics, often bifurcate into a long living, well organized multi-thread loop arcades. To describe this process we use the model of energetically open system, consisting of current carrying magnetic loops that interconnect a high β energy production region with a low β dissipation region through the resistive stresses. The model includes feedback managed by the transition region. Such a system may be driven into various dynamic forms including spontaneous process of self-organization. Title: Is Flux Submergence an Essential Aspect of Flux Emergence? Authors: Lites, B. W.; Frank, Z.; Shine, R. A.; Title, A. M.; Ichimoto, K. Bibcode: 2009ASPC..415..172L Altcode: High resolution Hinode Spectro-Polarimeter observations permit one to examine the detailed structure of the magnetic field vector in emerging flux regions. We find the field to have a concave-upward geometry on the smallest scales observed (0.3 arcsec), indicating the presence of U-loops at the sites of approaching and canceling opposite polarities. This structure suggests that reconnection is taking place at or below the surface, allowing the emerging flux to rid itself of its considerable mass burden. Supersonic down flows are often observed adjacent to, but not coincident with, the sites of canceling flux. We propose that these are the sites that drain the mass contained in the buoyantly-rising flux elements. The observations then suggest a process of sub-surface reconnection producing O-loops that then are forced to descend with the intergranular convective down flows, thus making flux submergence important to the larger scale flux emergence process. Title: Role of the Resistive and Thermal Instabilities in Dynamics of Quiescent Prominences Authors: Frank, Z.; Ryutova, M.; Berger, T. E.; Title, A. M.; Tarbell, T. D. Bibcode: 2009AGUFMSH41B1653F Altcode: We present the observations taken with the SOT instrument on Hinode in G-band and Ca H lines. High cadence data compiled in movies show clear evidence for several fundamental plasma instabilities. We combine the observational evidence and theoretical estimates to identify these instabilities. The following can be given as examples. (1) An analogue of the Kelvin-Helmholtz instability develops at the prominence/corona interface that manifests itself in growing ripples during a linear growth phase and may be followed by a nonlinear stage taking the form of an explosive instability corresponding to a CME ejection. This instability also includes the regime of "smoke ring" formation. (2) The appearence of "bubbles and spikes" typical to the Rayleigh-Taylor instability are observed. Their evolution and growth rates are found to be modified by both poloidal and toroidal components of magnetic field. (3) A resistive interchange instability, associated with an "unfavorable" magnetic field curvature relative to the density/temperature gradients, may be responsible for a hot barb formation, its evolution and collapse. Title: Origin of Filamentary Structures and Flows in Quiescent Prominences Authors: Ryutova, M.; Berger, T. E.; Tarbell, T. D.; Frank, Z.; Title, A. M. Bibcode: 2009AGUFMSH23B1540R Altcode: The paradox of fine vertical structure has usually referred to an apparent contradiction met when comparing vertical fine structures of quiescent prominences observed on the limb with the necessary horizontal magnetic field along their long axis. In addition to this fundamental problem, the very formation of fine vertical structures has been a long standing puzzle. Here we address these problems and show that considering the global structure of a prominence as a large scale skewed formation with toroidal and poloidal fields removes the paradox and allows derivation of dynamic stability criteria. This also includes the mechanism of the fine structure formation and peculiarities of downward mass motions. Theoretical estimates of key parameters are compared with the observations taken with the SOT instrument on Hinode. We find results of comparison very encouraging. For the approximate 3D reconstruction of the general shape of prominences, the STEREO A and B images have been used. Title: Has Hinode Revealed the Missing Turbulent Flux of the Quiet Sun? Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A. M.; Ichimoto, K.; Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S. Bibcode: 2009ASPC..405..173L Altcode: The Hinode Spectro-Polarimeter has revealed the presence of surprisingly strong horizontal magnetic fields nearly everywhere in the quiet solar atmosphere. These horizontal fields, along with measures of the vertical fields, may be the signature of the ``hidden turbulent flux'' of the quiet Sun. The measured horizontal fields average at least to 55 Gauss: nearly 5 times that of the measured longitudinal apparent flux density. The nature of these fields are reviewed, and discussed in the light of recent magneto-convection numerical simulations of the quiet Sun. Title: Mesoscale dynamics on the Sun's surface from HINODE observations Authors: Roudier, Th.; Rieutord, M.; Brito, D.; Rincon, F.; Malherbe, J. M.; Meunier, N.; Berger, T.; Frank, Z. Bibcode: 2009A&A...495..945R Altcode: 2009arXiv0902.2299R Context:
Aims: The interactions of velocity scales on the Sun's surface, from granulation to supergranulation are still not understood, nor are their interaction with magnetic fields. We thus aim at giving a better description of dynamics in the mesoscale range which lies between the two scales mentioned above.
Methods: We analyse a 48 h high-resolution time sequence of the quiet Sun photosphere at the disk center obtained with the Solar Optical Telescope onboard Hinode. The observations, which have a field of view of 100´´ × 100´´, typically contain four supergranules. We monitor in detail the motion and evolution of granules as well as those of the radial magnetic field.
Results: This analysis allows us to better characterize Trees of Fragmenting Granules issued from repeated fragmentation of granules, especially their lifetime statistics. Using floating corks advected by measured velocity fields, we show their crucial role in the advection of the magnetic field and in the build up of the network. Finally, thanks to the long duration of the time series, we estimate that the turbulent diffusion coefficient induced by horizontal motion is approximately 430 km2 s-1.
Conclusions: These results demonstrate that the long living families contribute to the formation of the magnetic network and suggest that supergranulation could be an emergent length scale building up as small magnetic elements are advected and concentrated by TFG flows. Our estimate for the magnetic diffusion associated with this horizontal motion might provide a useful input for mean-field dynamo models. Title: On the Penumbral Jetlike Features and Chromospheric Bow Shocks Authors: Ryutova, M.; Berger, T.; Frank, Z.; Title, A. Bibcode: 2008ApJ...686.1404R Altcode: We present observations of sunspot penumbrae obtained during the disk passage of AR 10923 (2006 November 10-20) with the SOT instrument on Hinode in 4305 Å G band and Ca II λ3968 H line. Along with recently discovered jetlike features (Katsukawa et al. 2007), we find other kinds of bright elongated transients abundantly pervading the entire penumbra and drifting as a whole in a direction almost perpendicular to their long axes. Their measured velocities strongly depend on their orientation with respect to the line of sight and range from simeq1 to simeq20 km s-1. We present quantitative analysis of these features and interpret them relative to our recent penumbral model (Ryutova et al. 2008) to show that they are produced by shocks resulting from a slingshot effect associated with the ongoing reconnection processes in neighboring penumbral filaments. Due to sharp stratification of the low atmosphere, postreconnection flux tubes moving upward quickly accelerate. At transonic velocities a bow (detached) shock is formed in front of the flux tube, as usually occurs in cases of blunt bodies moving with supersonic velocities. Observed parameters of transients are in good agreement with calculated parameters of bow shocks. On some, much more rare occasions compared to "drifting" bow-shock-type transients, there appear compact bright transients moving in the radial direction, along their long axis, and having velocities of 20-50 km s-1. We relate these features to a category of true microjets. Title: Magnetic Fields of the Quiet Sun: A New Quantitative Perspective From Hinode Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S. Bibcode: 2008ASPC..397...17L Altcode: This article summarizes results of studies presented in two papers already published: Lites et al. (2007a); Lites et al. (2007b). Please see these for further details. Title: Hinode Observations of Magnetic Elements in Internetwork Areas Authors: de Wijn, A. G.; Lites, B. W.; Berger, T. E.; Frank, Z. A.; Tarbell, T. D.; Ishikawa, R. Bibcode: 2008ApJ...684.1469D Altcode: 2008arXiv0806.0345D We use sequences of images and magnetograms from Hinode to study magnetic elements in internetwork parts of the quiet solar photosphere. Visual inspection shows the existence of many long-lived (several hours) structures that interact frequently and may migrate over distances of ~7 Mm over a period of a few hours. About a fifth of the elements have an associated bright point in G-band or Ca II H intensity. We apply a hysteresis-based algorithm to identify elements. The algorithm is able to track elements for about 10 minutes on average. Elements intermittently drop below the detection limit, although the associated flux apparently persists and often reappears some time later. We infer proper motions of elements from their successive positions and find that they obey a Gaussian distribution with an rms of 1.57 +/- 0.08 km s-1. The apparent flows indicate a bias of about 0.2 km s-1 toward the network boundary. Elements of negative polarity show a higher bias than elements of positive polarity, perhaps as a result of the dominant positive polarity of the network in the field of view or because of increased mobility due to their smaller size. A preference for motions in X is likely explained by higher supergranular flow in that direction. We search for emerging bipoles by grouping elements of opposite polarity that appear close together in space and time. We find no evidence supporting Joy's law at arcsecond scales. Title: Evershed Flows as an Integral Part of Penumbral Formation and its Fine Structure Authors: Ryutova, M.; Berger, T.; Lites, B.; Title, A.; Frank, Z. Bibcode: 2008AGUSMSP41B..07R Altcode: Observations of Evershed flows with the Solar Optical Telescope (SOT) on Hinode (Ichimito, Shine, Lites, et al. 2008, PASJ, 59, S593) showed that penumbral flows have small scale structures and much more complex properties than those of a simple outflow of material with unique direction and appearence. We address this problem and show that the flow properties are directly connected to the observed properties of penumbral filaments and are an integral part of penumbral development during sunspot formation. In our recent model (Ryutova, Berger, & Title, 2008, ApJ, 676, April), based on the observations that sunspot has a filamentary structure and consists of a dense conglomerate of non-collinear interlaced flux tubes, the penumbra is formed due to an on-going reconnection processes that leads to branching out of the peripheral flux tubes from the "trunk". As flux tubes have different parameters, branching occurs at different heights and with different inclinations, thus forming an "uncombed" penumbra. Each elemental act of reconnection generates an inevitable twist in the post-reconnection filaments that acquire a screw pinch configuration. This explains the remarkable dynamic stability of penumbral filaments and their observed properties, such as presence of dark cores, wrapping and spinning of filaments around each other, bright footpoints, etc. Here we show that propagation of twist along current carrying helical flux tubes is accompanied by plasma flows that may have diverse properties depending on the location of interacting flux tubes, their inclination and pitch. We apply the model to observations taken with the SOT instrument, which includes spectro-polarimetric data, and perform quantitative analysis. Title: The Horizontal Magnetic Flux of the Quiet-Sun Internetwork as Observed with the Hinode Spectro-Polarimeter Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S. Bibcode: 2008ApJ...672.1237L Altcode: Observations of very quiet Sun using the Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) aboard the Hinode spacecraft reveal that the quiet internetwork regions are pervaded by horizontal magnetic flux. The spatial average horizontal apparent flux density derived from wavelength-integrated measures of Zeeman-induced linear polarization is BTapp = 55 Mx cm -2, as compared to the corresponding average vertical apparent flux density of | BLapp| = 11 Mx cm -2. Distributions of apparent flux density are presented. Magnetic fields are organized on mesogranular scales, with both horizontal and vertical fields showing "voids" of reduced flux density of a few granules spatial extent. The vertical fields are concentrated in the intergranular lanes, whereas the stronger horizontal fields are somewhat separated spatially from the vertical fields and occur most commonly at the edges of the bright granules. High-S/N observations from disk center to the limb help to constrain possible causes of the apparent imbalance between | BLapp| and BTapp, with unresolved structures of linear dimension on the surface smaller by at least a factor of 2 relative to the SOT/SP angular resolution being one likely cause of this discrepancy. Other scenarios for explaining this imbalance are discussed. The horizontal fields are likely the source of the "seething" fields of the quiet Sun discovered by Harvey et al. The horizontal fields may also contribute to the "hidden" turbulent flux suggested by studies involving Hanle effect depolarization of scattered radiation. Title: Hinode Observations of Flux Emergence in Quiet and Active Regions Authors: Lites, B. W.; Centeno, R.; Kubo, M.; Socas-Navarro, H. Berger, T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S. Bibcode: 2008ASPC..383...71L Altcode: We review briefly the observational understanding of emergence of flux in both the quiet Sun and active regions in the light of first results from the joint Japan/US/UK Hinode mission. That spacecraft is now providing us with our first continuous, high resolution measurements of the photospheric vector magnetic field, along with high resolution observations of the thermal and dynamic properties of the chromosphere and corona. This review is intended to present a few very early results and to highlight the potential for discovery offered by this extraordinary new mission. The discovery of ubiquitous horizontal magnetic flux in the quiet internetwork regions is presented. Title: On the Chromospheric Micro-jets Associated with the Penumbral Filaments Authors: Ryutova, M.; Berger, T.; Tarbell, T.; Frank, Z.; Title, A. Bibcode: 2007AGUFMSH22A0843R Altcode: We present observations of sunspot penumbrae obtained during the disk passage of AR 10923 (November 10--20, 2006) with the Solar Optical Telescope (SOT) on the Hinode satellite. Co-aligned multi-hour movies taken simultaneously in several wavelengths show fine-scale dynamics at the sub-arcsecond level. The dynamics include helical flows along penumbral filaments, branching of filaments, and penumbral "micro-jets" recently described by Katsukawa et al. (AAS 210, 94.13). We present quantitative analyzes of the penumbral jets and interpret them relative to our recent model of penumbral filaments (Ryutova, Berger and Title, 2007, in "Collective phenomena in macroscopic systems", Ed. G. Bertin, et al., World Scientific) to show that the jets are the result of magnetic reconnection of the helical field lines in neighboring non-collinear filaments. Title: Transient Phenomena in Multi-thread Arcades of Coronal Loops Authors: Frank, Z.; Ryutova, M. Bibcode: 2007AGUFMSH22A0842F Altcode: The post-flare coronal loops having well defined filamentary structure, often appear as an arcades of thin magnetic threads resembling winding in a curved solenoid or a funnel. Compared to flare timescales, post-flare arcades are long living, well organized structures. Elemental filaments in arcades are, however, in highly dynamic state, showing oscillations, and harboring frequent microflares. These microflares often appear simultaneously in different places. Besides, many individual filaments produce homologous, repetitive microflares. Microflares are often accompanied by short living jets. We present the observations of these events using the data taken with SOT and XRT instruments on Hinode combined with the TRACE 195 ~Å coronal line. The object of the observation is AR 10930 which exhibited several flare events in December, 2006. After a major flare on 13 December, a typical "solenoidal" system of coronal threads was formed that lasted over 6 hours. The observed spatial and temporal regularities in appearence of the EUV transients can be well understood on basis of a spatio-temporal echoes resulted from nonlinear response of a system ("coupled oscillators") to impulsive disturbences associated with the changes in the photospheric magnetic fields. Observations in the SOT chromospheric lines show appearence of precursors of coronal jets and microflares. Title: Hinode Observations of Horizontal Quiet Sun Magnetic Flux and the ``Hidden Turbulent Magnetic Flux'' Authors: Lites, Bruce; Socas-Navarro, Hector; Kubo, Masahito; Berger, Thomas; Frank, Zoe; Shine, Richard A.; Tarbell, Theodore D.; Title, Alan M.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Tsuneta, Saku; Suematsu, Yoshinori; Shimizu, Toshifumi Bibcode: 2007PASJ...59S.571L Altcode: We present observations of magnetic fields of the very quiet Sun near disk center using the Spectro-Polarimeter of the Solar Optical Telescope aboard the Hinode satellite. These observations reveal for the first time the ubiquitous presence of horizontal magnetic fields in the internetwork regions. The horizontal fields are spatially distinct from the vertical fields, demonstrating that they are not arising mainly from buffeting of vertical flux tubes by the granular convection. The horizontal component has an average ``apparent flux density'' of 55Mxcm-2 (assuming the horizontal field structures are spatially resolved), in contrast to the average apparent vertical flux density of 11Mxcm-2. The vertical fields reside mainly in the intergranular lanes, whereas the horizontal fields occur mainly over the bright granules, with a preference to be near the outside edge of the bright granules. The large apparent imbalance of vertical and horizontal flux densities is discussed, and several scenarios are presented to explain this imbalance. Title: Penumbral Dynamics and its Manifestation in the Overlying Chromosphere Authors: Ryutova, Margarita; Berger, Thomas; Tarbell, Theodor; Frank, Zoe; Title, Alan Bibcode: 2007APS..DPPYP8056R Altcode: Mature sunspots are usually surrounded by penumbra - a dense conglomerate of a random interlaced flux tubes with varying inclinations. High resolution observations show a fine sub-structure of penumbral filaments and new regularities in their dynamics. These regularities fit well our recent model of penumbra based on cascading reconnection events occurring in the system of non-collinear flux tubes. Each act of reconnection generates twist in the reconnected filaments and facilitates the onset of a screw pinch instability, consistent with the observations showing that individual filaments are cylindrical helices with a pitch/radius ratio providing their stability. In addition, the post-reconnection products produce a sling-shot effect that generates oblique shocks and leads to appearence of a lateral jets. Here we report high resolution (120-180 km) high cadence (15-30 sec) observations taken with the Solar Optical Telescope (SOT) on the Hinode satellite. Co-aligned multi-hour movies taken simultaneously in several wavelengths show detailed behavior of penumbra filaments and their effect on the overlying chromosphere. We confirm the ubiquitous nature of penumbral micro-jets recently discovered by SOT instrument (Katsukawa et al. 2007, AAS 210, 94.13), and present quantitative analysis of chromospheric jets based on our recent model of penumbra. Title: Formation of Moving Magnetic Features and Penumbral Magnetic Fields with Hinode/SOT Authors: Kubo, Masahito; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Tsuneta, Saku; Suematsu, Yoshinori; Katsukawa, Yukio; Nagata, Shin'ichi; Tarbell, Theodore D.; Shine, Richard A.; Title, Alan M.; Frank, Zoe A.; Lites, Bruce; Elmore, David Bibcode: 2007PASJ...59S.607K Altcode: 2007arXiv0709.1853K Vector magnetic fields of moving magnetic features (MMFs) were well observed with the Solar Optical Telescope (SOT) aboard the Hinode satellite. We focused on the evolution of three MMFs with the SOT in this study. We found that an MMF having relatively vertical fields with the same polarity as the sunspot was detached from the penumbra around the granules appearing in the outer penumbra. This suggests that granular motions in the outer penumbra are responsible for disintegration of the sunspot. Two MMFs with polarity opposite to the sunspot are located around the outer edge of horizontal fields extending from the penumbra. This is evidence that the MMFs with polarity opposite to the sunspot are the prolongation of penumbral horizontal fields. Redshifts larger than the sonic velocity in the photosphere are detected for some of the MMFs with polarity opposite to the sunspot. Title: Emergence of Small-Scale Magnetic Loops in the Quiet-Sun Internetwork Authors: Centeno, R.; Socas-Navarro, H.; Lites, B.; Kubo, M.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Tsuneta, S.; Katsukawa, Y.; Suematsu, Y.; Shimizu, T.; Nagata, S. Bibcode: 2007ApJ...666L.137C Altcode: 2007arXiv0708.0844C We study the emergence of magnetic flux at very small spatial scales (less than 2") in the quiet-Sun internetwork. To this aim, a time series of spectropolarimetric maps was taken at disk center using the instrument SP/SOT on board Hinode. The LTE inversion of the full Stokes vector measured in the Fe I 6301 and 6302 Å lines allows us to retrieve the magnetic flux and topology in the region of study. In the example presented here, the magnetic flux emerges within a granular structure. The horizontal magnetic field appears prior to any significant amount of vertical field. As time goes on, the traces of the horizontal field disappear, while the vertical dipoles drift-carried by the plasma motions-toward the surrounding intergranular lanes. These events take place within typical granulation timescales. Title: Emerging And Rotating Magnetic Flux Structures Associated With Solar Eruptions In AR10930 As Observed By Hinode/SOT, TRACE, And SOHO/MDI Authors: Nightingale, Richard W.; Schrijver, C. J.; Frank, Z. A. Bibcode: 2007AAS...210.9423N Altcode: 2007BAAS...39..221N During the period of December 6-14, 2006 AR10930 produced 4 X-flares in what was otherwise a quiet solar minimum. The multiple flaring appears to be associated with small emerging and rotating magnetic flux structures around a larger stable sunspot. The eruptions were observed by several solar instruments, including the Solar Optical Telescope (SOT) on the recently launched Hinode Spacecraft, as well as TRACE and SOHO/MDI. The high resolution of SOT highlights the rotation of the small emerging flux regions, which can carry magnetic energy and helicity up into the solar atmosphere from the interior of the sun to help facilatate the eruptions. Images at several wavelengths from the suite of observational instrumentation mentioned above will be utilized to illustrate these events.

This work was supported by NASA in part under the TRACE contract NAS5-38099 and in part under the Hinode/SOT contract NNM07AA01C. Title: Magnetic Flux Emergence In The Quiet Sun Photosphere Authors: Centeno, Rebecca; Lites, B.; Socas-Navarro, H.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Tsuneta, S.; Katsukawa, Y.; Suematsu, Y.; Kubo, M.; Shimizu, T. Bibcode: 2007AAS...210.9406C Altcode: 2007BAAS...39..218C We study the emergence of magnetic flux at very small spacial scales (less than 1 arcsec) in the quiet Sun internetwork. To this aim, several time series of spectropolarimetric maps were taken at disk center using the instrument SP/SOT on board Hinode. The LTE inversion of the full Stokes vector measured in the Fe I 6301 and 6302 lines will allow us to retrieve the magnetic flux and topology in the region of study. We find that the magnetic flux emerges typically within the granular structures. In many cases, the horizontal magnetic field appears prior to any significant amount of vertical field. As time goes on, the traces of the horizontal field dissapear while the the vertical dipoles drift -carried by the plasma motions- towards the surrounding intergranular lanes. Sometimes they stay trapped there for a while but they eventually either disappear by disgregation/cancelation or agregate to other magnetic field concentrations giving rise to larger flux elements. The time scale of these events is of the order of 10-20 minutes. Title: Formation of Moving Magnetic Features and Penumbral Magnetic Fields Authors: Kubo, Masahito; Ichimoto, K.; Shimizu, T.; Tsuneta, S.; Suematsu, Y.; Katsukawa, Y.; Nagata, S.; Lites, B. W.; Frank, Z.; Tarbell, T. D.; Shine, R. A.; Title, A. M. Bibcode: 2007AAS...210.9410K Altcode: 2007BAAS...39..218K We investigate the formation process of Moving Magnetic Features (MMFs) observed with Hinode/SOT. Moving magnetic features are small magnetic elements moving outward in the moat region surrounding mature sunspots. We derive vector magnetic fields of MMFs around simple sunspots near the disk center. Most of MMFs with polarity opposite to the sunspot have large redshift around the penumbral outer boundary. We find that some of them have Doppler velocities of about 10 km/s and such large Doppler motion is observed only in the Stokes V profile. The Stokes Q and U profiles in the same pixel do not have any significant Doppler motions. Horizontal magnetic fields of the penumbra frequently extend to the moat region and the MMFs having horizontal fields with polarity same as the sunspot are formed. The MMFs with polarity opposite to the sunspot appear around the outer edge of the extending penumbral fields. We also find penumbral spines, which have more vertical magnetic fields than the surroundings, branch off at their outer edge and MMFs having relatively vertical fields with polarity same as the sunspot are detached from the outer edge of the branch. The branch of penumbral spine is formed when granular cells in the moat region go into the penumbra. Title: Ubiquitous Horizontal Magnetic Fields in the Quiet Solar Photosphere as Revealed by HINODE Meaurements Authors: Lites, Bruce W.; Socas Navarro, H.; Berger, T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Kubo, M.; Shimizu, T.; Nagata, S.; Hinode Team Bibcode: 2007AAS...210.6303L Altcode: 2007BAAS...39..171L Measurements with the HINODE Spectro-Polarimeter (SP) of the quiet Sun allow characterization of the weak, mixed-polarity magnetic flux at the highest angular resolution to date (0.3"), and with good polarimetric sensitivity(0.025% relative to the continuum). The image stabilization of the HINODE spacecraft allows long integrations with degradation of the image quality only by the evolution of the solar granulation. From the Stokes V profile measurements we find an average solar "Apparent Flux Density" of 14 Mx cm-2, with significant Stokes V signals at every position on the disk at all times. However, there are patches of meso-granular size (5-15") where the flux is very weak. At this high sensitivity, transverse fields produce measurable Stokes Q,U linear polarization signals over a majority of the area, with apparent transverse flux densities in the internetwork significantly larger than the corresponding longitudinal flux densities. When viewed at the center of the solar disk, the Stokes V signals (longitudinal fields) show a preference for occurrence in the intergranular lanes, and the Q,U signals occur preferably over the granule interiors, but neither association is exclusive.

Hinode is an international project supported by JAXA, NASA, PPARC and ESA. We are grateful to the Hinode team for all their efforts in the design, build and operation of the mission. Title: Moving Magnetic Features Observed in Photosphere, Chromosphere, and Transition Region Authors: Hagenaar, H. J.; Frank, Z. A. Bibcode: 2006ESASP.617E..64H Altcode: 2006soho...17E..64H No abstract at ADS Title: TRACE and SOHO/MDI Observations of Five X-Flares from AR10720, the "Fireworks Active Region", on January 15-20, 2005 Authors: Nightingale, R. W.; Frank, Z. A.; Metcalf, T. R.; Kang, C. A. Bibcode: 2005AGUSMSP21A..10N Altcode: Both TRACE and SOHO/MDI observed the five X-flares that were produced by AR10720 during January 15-20, 2005. This active region appears to be "special" because it is occurring so late in the solar cycle, about two-thirds of the way toward solar minimum. Also its structure is initially one large penumbral region with several umbral spots that are being stretched out east to west with rotating sunspots emerging in leading and trailing positions during the transit across the solar disk, similar to fireworks with pin-wheels attached. With a neutral line running almost east-west in between two of the stretched umbral regions and with opposite magnetic polarities on both sides of the neutral line adjacent to each other, the beta-delta region starts the "fireworks" with the first X-flare on January 15, continuing every one to one and one-half days over the next five days. Images and movies will be shown of these eruptive events in white light and 1600A from TRACE, and as magnetograms from MDI. Two of the three rotating sunspots also change their direction of rotation during this period. These X-flares add to those observed by TRACE since its launch in April 1998, all of which have been associated with rotating sunspots in the associated active regions. These X-flares consist of over half of the X-flares observed by GOES since April 1998 and many are associated with geo-effective CMEs in the form of solar energetic particle events. Rotating sunspots may be a good predictor of solar eruptions. This work has been supported by NASA, in part under the TRACE project at LMSAL (contract NAS5-38099) and in part under the MDI/SOHO project (NAG5-13261). Title: Solar Filaments and Photospheric Network Authors: Lin, Yong; Wiik, Jun Elin; Engvold, Oddbjørn; Van Der Voort, Luc Rouppe; Frank, Zoe A. Bibcode: 2005SoPh..227..283L Altcode: The locations of barbs of quiescent solar filaments are compared with the photospheric/chromospheric network, which thereby serves as a proxy of regions with enhanced concentrations of magnetic flux. The study covers quiet regions, where also the photospheric network as represented by flow converging regions, i.e., supergranular cell boundaries, contain largely weak magnetic fields. It is shown that close to 65% of the observed end points of barbs falls within the network boundaries. The remaining fraction points into the inner areas of the network cells. This confirms earlier findings (Lin et al., Solar Physics, 2004) that quiescent filaments are basically connected with weaker magnetic fields in the photosphere below. Title: Bright Points and Coronal Jets as Models for Eruptive Phenomena in the Solar Atmosphere Authors: Frank, Z. A.; Slater, G. L. Bibcode: 2002AAS...201.8304F Altcode: 2002BAAS...34.1242F Bright points in X-rays and EUV are an ever-present phenomena in the solar atmosphere and are often the origin of coronal jets. When bright points are examined at high resolution ( 1 arcesec or less) they show structures remarkably similar in morphology to larger scale coronal structures. Furthermore, their dynamics and evolution also show similarities to larger structures. We examine bright points and coronal jets in X-rays and EUV using Yohkoh SXT, TRACE, and EIT imagery in order to determine the extent to which they can be viewed as miniature counterparts of active regions. This work is supported by NASA contract numbers NAS8-40801, NAS5-38099, NAS5-32966, and Stanford University contract PR9162. Title: TRACE, SOHO/EIT, and SOHO/MDI Observations of AR0030, Including Rotating Sunspots and the July 15, 2002 X3.0 Flare in Ultraviolet and Extreme Ultraviolet Authors: Nightingale, R. W.; Shine, R. A.; Alexander, D.; Freeland, S. L.; Frank, Z. A.; Brown, D. S. Bibcode: 2002AGUFMSH52A0467N Altcode: On July 15, 2002 TRACE and several SOHO instruments observed an X3.0 flare in AR0030 near 2000 UT. During this period TRACE was primarily observing in its 1600Å ultraviolet (UV) channel (most sensitive to temperatures around 100,000 K in the flare). The 195Å extreme ultraviolet (EUV) channel of SOHO/EIT (which is most sensitive to about 1.6 MK) will be utilized in this poster, in addition to the magnetic field measurements of SOHO/MDI during this event period. TRACE followed the active region for over 10 days, starting about 4 days before the flare. Broadband white light TRACE images of the photosphere indicate that one or more of the sunspots were rotating, a possible precursor to the flare. Images and movies of AR0030 in the various wavelengths will be shown. The flare region was so intense in the TRACE UV that it is very difficult to show both the quiescent and flaring regions, so the UV movie will focus on the flaring plasma with its 2 eruptions. In the EIT EUV, more coronal structure away from the flare can be seen. Analysis of the rotational rates of the sunspots will be given along with their possible coupling to the flare. This work was supported by NASA under contract NAS5-38099. Title: Photospheric Magnetic Activities Responsible for Soft X-Ray Pointlike Microflares. I. Identifications of Associated Photospheric/Chromospheric Activities Authors: Shimizu, T.; Shine, R. A.; Title, A. M.; Tarbell, T. D.; Frank, Z. Bibcode: 2002ApJ...574.1074S Altcode: By combining Yohkoh soft X-ray images with high-resolution magnetograms simultaneously obtained at La Palma, we studied photospheric magnetic signatures responsible for soft X-ray microflares (active-region transient brightenings). In order to have a reliable correspondence between the photosphere and the corona, we studied 16 pointlike transient brightenings with X-ray source size less than 10" occurring during periods when the seeing was excellent at La Palma, although a lot of transient brightenings were in forms of multiple- or single-loop structures. In half of the studied events, small-scale emergences of magnetic flux loops are found in the vicinity of the transient brightenings. Six events of that half show that a small-scale flux emergence accompanies the X-ray brightening 5-30 minutes prior to its onset. In the other half of the studied events, no apparent evolutionary change of magnetic flux elements is found associated with the transient brightenings. Many of these events are found in rather strong magnetic fields, such as sunspots and pores, implying that small-scale changes of magnetic flux are obscured or suppressed by strong magnetic fields. The horizontal plasma flows derived from local cross-correlation tracking of granules in continuum images are suppressed at the feet of some X-ray transient brightenings. Title: Flow Map Studies of Supergranule and Mesogranule Evolution from TRACE Authors: Shine, R. A.; Frank, Z. A.; Tarbell, T. D.; Simon, G. W. Bibcode: 2001AGUFMSH11A0702S Altcode: From 00:44 UT 22-April-2000 to 00:09 UT 29-April-2000 we obtained a nearly continuous set of white light images using the Transition Region and Corona Explorer (TRACE) satellite. A 384x384 arc second field of view was used that tracked solar rotation from Stonyhurst longitudes 45E to 45W along the solar equator. The total time is nearly 7 days with images taken every minute over most of the interval. The largest temporal gap was 45m and there were only 9 gaps longer than 10m. The area was mostly free of active regions. These images are broad band white light with 0.5 arc second pixels. Granulation is well defined and we used local correlation techniques (LCT) to compute flow maps of the horizontal velocities with a resolution of about 5 arc seconds. The flow map resolution and quality suffer somewhat near the longitude extrema but the maps are usable throughout the 7 days to define supergranules and mesogranules. We compute horizontal divergence to study the motions of mesogranules and the evolution and lifetime of supergranules. When enough telemetry capacity was available, we also obtained co-spatial images in the TRACE Fe IX/X 171Å channel and the 1600Å channel. We use these to study the response of the corona and chromosphere to the photospheric motions. During times with particularly high telemetry throughput, we took white light images every 30 seconds. This allows us to empirically determine the noise in our flow maps using two interleaved and disjoint sets of white light data, each with one minute intervals. This work was supported by NASA contract NAS5-38099. Title: More Rotating Sunspot Observations by TRACE With Twisting EUV Coronal Fans Authors: Nightingale, R. W.; Shine, R. A.; Brown, D. S.; Wolfson, C. J.; Frank, Z. A.; Title, A. M. Bibcode: 2001AGUSM..SH41B11N Altcode: In an on-going search several sunspots, rotating about their umbral centers, have been identified in TRACE photospheric white light (WL) images. In many cases the rotation can also be seen in the corresponding UV (1600 Å) and/or EUV (171, 195 Å) images. Preliminary analysis of one such rotating sunspot and the coronal response to the rotation, observed in AR9114 on August 8-10, 2000, was presented at the fall AGU meeting (Nightingale et al., Abstract SH11A-10, EOS, AGU 2000 Fall Meeting, Vol. 81, p. F977, Nov. 2000). Further detailed analysis and modeling of this event, where loops appear to cross over one another, is in progress. Meanwhile, we are finding other examples within the TRACE data set. Twisting EUV coronal fans have been observed above rotating sunspots on August 16, 1999 for AR8667, where a sigmoid was visible in Yohkoh SXT data, and on May 20, 2000. Several rotating sunspots were also seen in the active region of the July 14, 2000 Bastille Day event. More recent rotations observed only in WL and UV occurred on December 11 and 22, 2000. Movies of some of these rotations will be shown, as well as magnetic field data from MDI on SOHO where available. Analysis of the rotational rates of the sunspots will be given. These observations display the coupling of the magnetic field from the photosphere into the corona. This work was supported by NASA under contract NAS5-38099. Title: Instrumental Effects and their Removal from TRACE Images Authors: Tarbell, T. D.; Nightingale, R. N.; Metcalf, T. R.; Frank, Z. A.; TRACE Team Bibcode: 2000SPD....31.0291T Altcode: 2000BAAS...32..827T TRACE raw images often show fine structures at such high contrast that compensation for instrumental effects is not necessary to study their morphology and evolution. Nevertheless, TRACE team members have gradually been developing the techniques and calibrations necessary to understand and (sometimes) remove the principal instrumental degradations. These degradations include CCD pedestal variation with temperature and time, flat-field response, CCD sensitivity loss varying with position and wavelength, electrical interference during CCD readout, permanent dim pixels, intermittent hot pixels, overall system point spread function, diffraction of EUV radiation by the front entrance filters, scattered light at off-limb pointings, tracks of electrons and protons from the radiation belts, and artifacts from JPEG compression of solar strucures and the above defects. Characterization and removal of some of these will be presented in the poster, such as the following. A deconvolution routine can partially compensate for the EUV diffraction, which is described in the adjacent poster by Frank et al. White light flat fields are derived using the Kuhn-Lin algorithm. CCD sensitivity degradation (presumably lumogen damage) is measured both from crude UV and EUV flat fields and from mission-long analysis of synoptic disk center images; combining these results with the WL flats yields flat fields at all wavelengths. Some information on scattered light and point spread functions are obtained from the August, 1999, eclipse observations and the Mercury transit. SSW routines for dealing with some of these degradations will be identified. This work is supported by the TRACE project at LMSAL (contract NAS5-38099). Title: Diffraction Pattern Analysis of Bright TRACE Flares Authors: Frank, Z. A.; Lin, A. C.; Nightingale, R. W.; Tarbell, T. D. Bibcode: 2000SPD....31.0290F Altcode: 2000BAAS...32..827F A study of the diffraction patterns seen in TRACE images of bright flares was undertaken to better understand the properties of the telescope. The pattern caused by light from a bright solar flare passing through the wire mesh in front of the telescope has been examined, and a method has been developed to use this pattern to determine the zeroth order intensity of bright flares. This intensity cannot usually be measured directly due to saturation of the Analog to Digital Converter (ADC) electronics in the CCD camera package. The validity of this method has been tested on dimmer flares, whose intensity do not saturate the ADC. The diffraction pattern allows us to measure intensities far brighter than the camera package permits. For the bright flare on May 16, 1999 at 13:49:21 UT the range has been effectively increased by at least 41 times. The light defracted away from any point was observed to be 18%, a significant amount which affects the contrast of TRACE images. An accurate determination of the ratio of the square slit size to slit spacing of the wire mesh has been obtained. This is an important parameter for a deconvolution routine that can remove the diffraction patterns from the image (see adjacent SPD poster paper by Tarbell et al.). Wavelength dispersion, the phenomenon that as the higher order diffracted peaks lie further from the center they spread out until double peaks are observed, has also been examined as part of this study. This effect is observable because there are two principal wavelengths, Fe IX at 171.06 Angstroms and Fe X at 174.52 Angstroms in the TRACE 171 Angstroms passband used in present analysis. This study is a part of the TRACE Team educational outreach program and is supported by contract NAS5-38099 at LMSAL. Title: The Postflare Loops and the Nearby Active Chromosphere of 1992 June 26: Addendum Authors: Malherbe, J. -M.; Tarbell, T.; Wiik, J. E.; Schmieder, B.; Frank, Z.; Shine, R. A.; van Driel-Gesztelyi, L. Bibcode: 1998ApJ...495..502M Altcode: Video segments are presented that were processed from a quantitative study of the dynamics of the evolution of Hα postflare loops developed after a large solar flare. The high spatial resolution of the Swedish Vacuum Solar Telescope (SVST) at La Palma provided a unique set of data for such an event. Title: Photospheric flows as measured by SOI/MDI Authors: Hurlburt, N.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Simon, G. Bibcode: 1997ASSL..225..285H Altcode: 1997scor.proc..285H On 2 February and 7 March 1996, MDI on the SOHO spacecraft ran several hours to provide high resolution continuum images to map the horizontal flows near the equator and pole by correlation tracking. Here we present preliminary results on the performance of the tracking technique in measuring the differential rotation profile. These preliminary results are compared with each other and with corresponding results of previous studies. Title: The Postflare Loops and the Nearby Active Chromosphere of 1992 June 26 Authors: Malherbe, J. -M.; Tarbell, T.; Wiik, J. E.; Schmieder, B.; Frank, Z.; Shine, R. A.; van Driel-Gesztelyi, L. Bibcode: 1997ApJ...482..535M Altcode: The main objective of this paper is to present a quantitative study of the dynamics of the evolution of Hα postflare loops developed after a large solar flare and the processed videos produced from the observations. The high spatial resolution of the Swedish Vacuum Solar Telescope (SVST) at La Palma has provided a unique set of data for such an event. A Gaussian fitting method is proposed to derive intensities and Doppler shifts from observations taken at three wavelengths (Hα center and Hα +/- 0.07 nm). Moving condensations or ``blobs'' of cold material provide transverse velocities, which, together with the radial component, enable us to derive their velocity vector magnitude. Plasma velocities are around free-fall velocities near the top of the loops but are significantly smaller close to their footpoints, suggesting a deceleration mechanism. The loops are anchored in the chromosphere, which shows tremendous activity in the active region and in the nearby ``quiet Sun.'' Spicules and ejection of plasmoids are also observed at the limb. Title: Comparison of supergranular flows from doppler and local correlation tracking velocities Authors: Frank, Z.; Hurlburt, N.; Shine, R.; Tarbell, T.; Simon, G.; Strous, L.; Matt, S. Bibcode: 1997SPD....28.0259F Altcode: 1997BAAS...29..903F Measurements of the flows in the solar photosphere rely upon two techniques: doppler measurements of the line-of-sight velocity or tracking of features or patterns moving perpendicular to the line-of-sight. These methods have differing characteristics. Doppler measurements can easily measure surface flows near the limb which are not seriously contaminated by p-modes or other solar sources. However, they require excellent instrument calibration over the full field of view. Even then vertical flows within supergranules are barely detectable. Correlation and feature tracking have proven useful for estimating transverse velocity using granules and other tracers. Nevertheless, they can be degraded by the intensity variations of p-modes and possibly other oscillatory motions, as well as by effects of limb darkening and foreshortening. The two methods would both be strengthened through detailed comparisons. Data collected by MDI/SOHO is ideal for this purpose. The data is co-spatial and co-temporal, and is all obtained through the same instrument. We compare Doppler velocities with those obtained through correlation tracking using high-resolution MDI/SOHO images. We focus on motions at positions exceeding 30 degrees from disk center. After taking projection effects into account, we combine the two measurements to form a three-dimensional picture of the flows in the average supergranule. This work was supported by NASA Grant NAG5-3077 at Stanford and Lockheed Martin, and by AFOSR and the Fellows Program of AF Phillips Lab at NSO/SP. Title: Initial Results from SOI/MDI High Resolution Magnetograms Authors: Title, A.; Tarbell, T.; Frank, Z.; Schrijver, C.; Shine, R.; Wolfson, J.; Zayer, I.; Scherrer, P.; Bush, R.; Deforest, C.; Hoeksema, T. Bibcode: 1996AAS...188.6915T Altcode: 1996BAAS...28..938T The Michelson Doppler Imager (MDI) on SoHO takes magnetogram s with resolutions of 1.2 (high resolution) and 4 (full disk) arcseconds. Movies of 16 hour duration have been constructed in full disk and high resolution mode. High resolution movies of the south polar region also have been obtained. In sums of nine high resolution magnetograms it is possible to detect fields as low as 5 gauss and total fluxes as low as 5 10(1) 6 Mx. In mid latitude regions new flux is observed to emerge everywhere. At all latitudes below 60 degrees flux is mixed on the scale of supergranulation. In the polar region above 60 degrees only fields of a single polarity are observed above the detection limit. Title: Preliminary SOI/MDI Observations of Surface Flows by Correlation Tracking in the Quiet Solar Photosphere and an Emerging Active Region Authors: Tarbell, T.; Frank, Z.; Hurlburt, N.; Saba, J.; Schrijver, C.; Shine, R.; Title, A.; Simon, G.; Strous, L. Bibcode: 1996AAS...188.6914T Altcode: 1996BAAS...28..937T The extended observation of the solar surface with frequent sampling provided by MDI on SoHO offers the chance to observe the evolution of supergranules and to measure surface flows associated with active regions and perhaps larger scale zonal and meridonal flows. We have used local correlation tracking of the granulation pattern for measuring surface flows from MDI high resolution continuum images. The datasets consist of 1024 x 1024 pixel images collected with a cadence of one minute and extending many hours each. The images are typically centered upon the central meridian of the sun and offset to the north of sun center, spanning roughly 40 degrees of solar longitude and from approximately -10 to +30 degrees of solar latitude. The latitude dependence of the differential rotation is evident. We present preliminary results of our search for signatures of mesogranules, supergranules and giant cells. On 23 Feb. 1996, we obtained a 12-hour continuous sequence including quiet sun near disk center and NOAA region 7946 at about N08 E30. The active region grew rapidly over this interval, forming several sunpots. We show preliminary comparisons of the measured flow fields with coaligned SOI/MDI magnetograms taken at 15-minute intervals. The SOI/MDI program is supported by NASA grant NAG5-3077. Title: SOI/MDI Measurements of Horizontal Flows in the South Polar Region of the Sun by Correlation Tracking and Doppler Shifts Authors: Simon, G.; Frank, Z.; Hurlburt, N.; Schrijver, C.; Shine, R.; Tarbell, T.; Title, A.; Deforest, C. Bibcode: 1996AAS...188.6913S Altcode: 1996BAAS...28R.937S On 7 March 1996, the SOHO spacecraft was offset from its usual disk center pointing for an 11-hour observation of the South Polar region. MDI took a continuous time series of high resolution longitudinal magnetograms during this period, in support of the SOHO-wide Joint Observing Program on polar plumes. It also ran several hours each of two other programs: one to map the horizontal flows near the pole by correlation tracking and Doppler shifts, and another to study wave propagation (e.g., by time-distance helioseismology) at these high latitudes. In this poster we present preliminary results from the first program. Both techniques yield measurements of the differential rotation profile near the pole and of horizontal flows of supergranulation. These results are compared with each other and with corresponding measurements in low latitudes. The location of magnetic features in the horizontal flows is also shown. The SOI/MDI program is supported by NASA grant NAG5-3077. Title: Photospheric Surface Flows and Small Magnetic Structures in Sunspot Moats Authors: Shine, R. A.; Title, A.; Frank, Zoe; Scharmer, G. Bibcode: 1996AAS...188.3501S Altcode: 1996BAAS...28Q.871S We have computed horizontal flow maps of the photosphere around and within three different sunspots using high spatial resolution continuum movies obtained at the Swedish Vacuum Solar Telescope on La Palma on June 5, 1993, August 29, 1993, and July 14, 1994. Two of the data sets also included magnetograms and dopplergrams. A new feature found in the flow maps is azimuthal structure in the moat flows surrounding sunspots. Instead of a simple radial flow, there are zones of azimuthal divergence and convergence resulting in radial ``spokes'' of convergence. These are not uniformly distinct around the entire circumference but are seen in part of the surrounding area for all 3 sunspots. The angular spacing is about 10 to 20 degrees and the pattern persists for several hours. For one of the sunspots, we have concurrent movies made with a 3 Angstrom wide K line filter. A time average of these images shows bright spokes in the K line congruent with the convergence spokes. Much of the magnetic flux that is continually emerging and moving outward in the moat is in the vicinity of the ``spokes.'' In addition, these data show several good examples of so called ``streakers.'' These are small bright structures seen in continuum movies that appear to be emitted from the outer edge of the penumbral and travel a few thousand km at about 2 to 3 km/s before fading. We find that these are associated with a magnetic field of opposite polarity to the sunspot and that they travel toward another larger and slower moving magnetic feature with the same polarity as the sunspot. When the streaker catches up, it disappears, sometimes coincident with a brightening of the merged feature which continues outward at the previous velocity, about 0.5 km/s. This work was supported by NSF grant ATM-9213879, NASA contracts NAS8-39746 and NAS8-39747, Lockheed Independent Research Funds, and the Swedish Royal Academy of Sciences. Title: Heating of Active Region Corona by Transient Brightenings (Microflares) Authors: Shimizu, T.; Tsuneta, T.; Title, A.; Tarbell, T.; Shine, R.; Frank, Z. Bibcode: 1996mpsa.conf...37S Altcode: 1996IAUCo.153...37S No abstract at ADS Title: The Possible Ascent of a Closed Magnetic System through the Photosphere Authors: Lites, B. W.; Low, B. C.; Martinez Pillet, V.; Seagraves, P.; Skumanich, A.; Frank, Z. A.; Shine, R. A.; Tsuneta, S. Bibcode: 1995ApJ...446..877L Altcode: We present a comprehensive interpretation of the evolution of a small magnetic region observed during its entire disk passage. The vector magnetic field measurements from the Advanced Stokes Polarimeter, along with Hα and magnetogram measurements from the Lockheed SOUP instrument operating at the Swedish Solar Observatory on La Palma, and soft X-ray images from the Yohkoh satellite support the hypothesis that we have observed the passage of a nearly closed magnetic system through the photosphere into the corona. The observations suggest that as the magnetic flux begins to emerge into the photosphere it shows a rather simple geometry, but it subsequently develops a small δ-sunspot configuration with a highly sheared vector field along the polarity inversion line running through it. At that stage, the vector field is consistent with a concave upward magnetic topology, indicative of strong electric currents above the photosphere. An Hα prominence is found above this inversion line when the δ-sunspot is fully formed. These observed features and the sequence of events are interpreted in terms of a nearly closed magnetic system that rises through the photosphere into the corona as a result of magnetic buoyancy. The magnetic system persists in the corona well after the dark δ-sunspot has disappeared in the photosphere We suggest that this coronal structure is in quasi-static equilibrium with its buoyancy partially countered by the weight of the plasma trapped at the bottom of closed magnetic loops. The plausibility of such a scenario is demonstrated by a three-dimensional magnetostatic model of the emergence of a closed, spheroidal magnetic system in the corona, in which the Lorentz force arising from cross-field currents is balanced by the gravitational and pressure forces. This theoretical model carries many features in common with the observed morphology of our active region. Title: Flux Emergence in a Sunspot Moat and Young Active Region Authors: Title, A. M.; Frank, Z. A.; Shine, R. A.; Tarbell, T. D.; Simon, G. W.; Brandt, P. N. Bibcode: 1995SPD....26.1007T Altcode: 1995BAAS...27..978T No abstract at ADS Title: Flux Emergence in the Sunspot Moat Authors: Title, A. M.; Shine, R. A.; Frank, Z. A.; Simon, G. W.; Brandt, P. N. Bibcode: 1994AAS...185.8602T Altcode: 1994BAAS...26.1464T On 13-15 June 1994 we obtained simultaneous movies of a sunspot in NOAA active region 7731 through a 3 Angstroms band K line filter, the LPARL tunable filter, and an 8 Angstroms G band filter. The data sets allow us to make aligned magnetic, continuum, Doppler, K line, and G band movies. The sunspot had a well developed moat. Flux emergence occured throughout the moat. The initial signature of the emergence was a transient dark elongated structure in the K line images that was aligned radially with respect to the spot. Bright point pairs appeared at the ends of these features in the K line and G band shortly after their emergence. Magnetic field is observed cospatial with the K line bright point pairs. The magnetic polarity of the end of the pair closest to the spot is the same as the spot. The pairs of bright points move across the moat in a radial direction away from the spot. When the pairs reach the moat boundary the leading bright point merges with a moat feature and the two disappear. The leading bright point's field and the moat field cancel, since the moat boundary and the spot have the same polarity. We believe that these features are different from the long observed moving magnetic features associated with sunspots. Title: High-Resolution Observations of the Evershed Effect in Sunspots Authors: Shine, R. A.; Title, A. M.; Tarbell, T. D.; Smith, K.; Frank, Z. A.; Scharmer, Goran Bibcode: 1994ApJ...430..413S Altcode: High spatial resolution movies of sunspots taken at the Swedish Solar Observatory on La Palma reveal that the Evershed effect is time dependent. Outward proper motions are visible in both the continuum and Dopplergrams. These can be tracked over most of the width of the penumbra and overlap regions that show inward moving penubral grains. The radial spacing between the moving structures is about 2000 km, and they exhibit irregular repetitive behavior with a typical interval of 10 minutes. These are probably the cause of 10 minutes oscillations sometimes seen in a penumbral power spectra. Higher velocities are spatially correlated with the relatively darker regions between bright filaments. Regions with a strong variation in the Doppler signal show peak-to-peak modulations of 1 km/s on an average velocity of about 3-4 km/s. The proper motion velocity is approximately constant from the iner penumbra and generally larger than the Doppler velocity when both are interpreted as projections of horizontal motion. Regions where thay are consistent suggest a typical horizontal velocity of 3.5 km/s. Some proper motion velocites as high as 7 km/s are seen, but these are less certain. The temporal behavoir shows a correlation between increased Doppler signal and increased continuum intensity, the opposite of the spatial correlation. When spatially averaged across filaments and over time, the averaged Evershed effect has a peak horizontal component near the outer edge of the penumbra of 2.0 km/s with evidence for a 200-400 m/s upward component. The latter depends on an uncertain absolute velocity calibration. If real it could be an actual upward component or a penumbral analogue of the convective blueshift seen in the quiet Sun. Title: Dynamics of the Evershed effect Authors: Shine, R. A.; Title, A. M.; Tarbell, T. D.; Smith, K.; Frank, Z. A.; Scharmer, G. Bibcode: 1994ASIC..433..197S Altcode: No abstract at ADS Title: Vector-Stokes polarimetry in a sunspot Authors: Hofmann, A.; Shine, R. A.; Frank, Z. A.; Schmidt, W.; Balthasar, H. Bibcode: 1994smf..conf..204H Altcode: No abstract at ADS Title: High resolution vector polarimetry of sunspot magnetic fields. Authors: Balthasar, H.; Hofmann, A.; Schmidt, W.; Shine, R. A.; Frank, Z. A. Bibcode: 1994AGAb...10..112B Altcode: No abstract at ADS Title: Solar Coronal Magnetic Field Topology Inferred from High Resolution Optical and X-ray Movies Authors: Tarbell, T.; Frank, Z.; Hurlburt, N.; Morrison, M.; Shine, R.; Title, A.; Acton, L. Bibcode: 1993BAAS...25.1208T Altcode: No abstract at ADS Title: La Palma Observations During the CoMStOC'92 Campaign Authors: Shine, R.; Tarbell, T.; Topka, K.; Frank, Z.; Title, A.; Scharmer, G. Bibcode: 1993BAAS...25S1223S Altcode: No abstract at ADS Title: ``The Active Sun'': Educational Videotapes on Solar Physics for College Astronomy Authors: Hurlburt, N.; Title, A.; Tarbell, T.; Frank, Z.; Topka, K.; Shine, R. Bibcode: 1993AAS...182.1002H Altcode: 1993BAAS...25..809H We present a series of short, educational documentaries on solar physics aimed at college-level general astronomy courses. These tapes highlight recent advances in high-resolution solar astronomy and in theoretical and computational modeling of solar physics with particular focus on dynamical phenomena. The relevant physical mechanisms, theoretical interpretations and observational techniques are discussed. These include granulation, the theory of convection, five-minute oscillations, sunspots, magnetic fields, seeing and dopplergrams. VHS tapes are available to researchers and educators through a variety of distributors. This work supported by Lockheed Independent Research Funds. Title: Solar Coronal Magnetic Field Topology Inferred from High Resolution Optical and X-ray Movies Authors: Tarbell, T.; Frank, Z.; Hurlburt, N.; Morrison, M.; Shine, R.; Title, A.; Acton, L. Bibcode: 1993AAS...182.4805T Altcode: 1993BAAS...25R.880T We are using high resolution digital movies of solar active regions in optical and X-ray wavelengths to study solar flares and other transients. The optical movies were collected at the Swedish Solar Observatory on La Palma using the Lockheed tunable filtergraph system, in May - July, 1992. They include longitudinal and transverse magnetograms, H-alpha Doppler and intensity images at many wavelengths, Ca K, Na D, and white light images. Simultaneous X-ray images from Yohkoh are available much of the time. We are learning several ways to establish the connectivity of some coronal magnetic field lines. Some of the clues available are: magnetic footpoint polarities and transverse field directions; H-alpha fibrils and loops seen in several wavelengths; proper motion and Doppler shifts of blobs moving along field lines; footpoint brightening in micro-flares; spreading of flare ribbons during gradual phases of flares; X-ray morphology and correlations with H-alpha; and draining of flare loops. Examples of each of these will be shown on video. This work is supported by NASA Contracts NASW-4612 and NAS8-37334 and by Lockheed Independent Research Funds. Title: On the Magnetic and Velocity Field Geometry of Simple Sunspots Authors: Title, Alan M.; Frank, Zoe A.; Shine, Richard A.; Tarbell, Theodore D.; Topka, Kenneth P.; Scharmer, Goran; Schmidt, Wolfgang Bibcode: 1993ApJ...403..780T Altcode: It is presently shown that a simple sunspot model with azimuthal variations in inclination, but lacking azimuthal field-strength variations, is free from azimuthal Lorentz forces. The meridional currents arising from the inclination variations are parallel to the field lines, suggesting that a cylindrically symmetric magnetostatic sunspot model can be perturbed into one with azimuthal variations in inclination with adjustment of the meridional force balance. Title: The High-Frequency P-Mode Spectrum Authors: Milford, P. N.; Scherrer, P. H.; Frank, Z.; Kosovichev, A. G.; Gough, D. O. Bibcode: 1993ASPC...42...97M Altcode: 1993gong.conf...97M No abstract at ADS Title: High Resolution Magnetic Field Measurements in the Sunspot Photosphere (Invited) Authors: Hofmann, A.; Schmidt, W.; Balthasar, H.; Tarbell, T. T.; Frank, Z. A. Bibcode: 1993ASPC...46...11H Altcode: 1993IAUCo.141...11H; 1993mvfs.conf...11H No abstract at ADS Title: White-light movies of the solar photosphere from the SOUP instrument on Spacelab 2 (Advances in Space Research 1986) Authors: Title, A. M.; Tarbell, T. D.; Simon, G. W.; Acton, L.; Duncan, D.; Ferguson, S.; Finch, M.; Frank, Z.; Kelly, G.; Lindgren, R.; Morrill, M.; Pope, T.; Reeves, R.; Rehse, R.; Shine, R.; Topka, K.; Harvey, J.; Leibacher, J.; Livingston, W.; November, L. Bibcode: 1993inas.book..100T Altcode: No abstract at ADS Title: Polarimetry and spectroscopy of a simple sunspot. I - On the magnetic field of a sunspot penumbra Authors: Schmidt, W.; Hofmann, A.; Balthasar, H.; Tarbell, T. D.; Frank, Z. A. Bibcode: 1992A&A...264L..27S Altcode: We investigate the magnetic field structure of a medium sized sunspot using high resolution magnetograms and spectrograms and derive a relationship between the brightness of penumbral structures and the inclination of the magnetic field. The field inclination to the spot normal is larger in the dark structures than in the bright ones. We show that the field strength does not vary between dark and bright structures. At the inner penumbral boundary the field strength is 2000 Gauss and about 1000 Gauss at the outer penumbral edge. The line-of sight component of the material flow decreases rapidly within one arcsecond at the photospheric boundary of the spot. Title: High resolution observations: the state of the art and beyond. Authors: Title, A.; Tarbell, T.; Shine, R.; Topka, K.; Frank, Z. Bibcode: 1992ESASP.344....9T Altcode: 1992spai.rept....9T Excellent telescopes on excellent sites with fast digital CCD cameras and special purpose computers allow the collection of broad band images at just the instants of good seeing. This has resulted in nearly optimal movies of the solar surface for several hours. When longer exposures are required for narrowband filtergrams or spectra it is not enough to capture single images. However, big fast memories allow the collection of many selected low signal-to-noise ratio images in real time, which can be summed to achieve the desired signal to noise ratios. Adaptive optics shows promise of diffraction limited images for limited fields of view. Nevertheless, groundbased observations will always be limited in their duration, uniformity, and resolution qualities which are essential for understanding the development and evolution of small scale processes. Until there are observations in space we will not be able to completely understand either the processes in the solar atmosphere or how processes occurring at different height are interrelated. Title: Evolution and advection of solar mesogranulation Authors: Muller, Richard; Auffret, Herve; Roudier, Thierry; Vigneau, Jean; Simon, George W.; Frank, Zoe; Shine, Richard A.; Title, Alan M. Bibcode: 1992Natur.356..322M Altcode: GRANULAR structure on the Sun's surface, with a typical scale of 1-2 Mm, has been known since 1800, and one hundred years ago, with the first observations by spectroheliograph1,2, a mesh-like bright network was found with a characteristic scale of 30 Mm (40''). This pattern was found, thirty years ago, to be coincident with close-packed convective cells ('supergranulation') revealed by Doppler observations3-5 to be nestling inside the bright network. More recently6,7 an intermediate 'mesogranular' structure was found, with a characteristic scale of 3-10 Mm. We have obtained a three-hour sequence of observations at the Pic du Midi observatory which shows the evolution of mesogranules from appearance to disappearance with unprecedented clarity. We see that the supergranules, which are known to carry along (advect) the granules with their convective motion, also advect the mesogranules to their boundaries. This process controls the evolution and disappearance of mesogranules. Title: High Resolution Observations of the Magnetic and Velocity Field of Simple Sunspots Authors: Title, Alan M.; Frank, Zoe A.; Shine, Richard A.; Tarbell, T. D.; Topka, K. P.; Scharmer, Goran; Schmidt, Wolfgang Bibcode: 1992ASIC..375..195T Altcode: 1992sto..work..195T We have observed the disk passage of relatively simple round sunspots using a narrowband filter and a large format CCD detector and have created magnetograms, Dopplergrams, and continuum images nearly simultaneously. In addition the spectral resolution of the filter allows the construction of 'spectra' for all points in the field of view. The mean inclination of the magnetic field increases from 45-50 deg to 70-75 deg across the penumbra and there is a fluctuation of the inclination angle about the mean of about 4 +/- 18 deg. The variation in inclination is large enough that substantial amounts of magnetic field are parallel to the solar surface from the mid to outer penumbra. The Evershed flow tends to occur in the regions where the magnetic field is horizontal. This suggests that the Evershed flow is confined to the regions of horizontal fields. We show that a simple sunspot model with azimuthal variations in inclination but no azimuthal variations of field strength is free from azimuthal Lorentz forces. The meridional component of the currents which arise from the azimuthal variation in inclination are parallel to the field lines. This suggests that a cylindrically symmetric magnetostatic sunspot model can be perturbed into one with azimuthal variations in inclination with some adjustment in the meridional force balance. Title: On the magnetic field of a sunspot penumbra. Authors: Balthasar, H.; Schmidt, W.; Hofmann, A.; Tarbell, T. D.; Frank, Z. A. Bibcode: 1992AGAb....7..153B Altcode: No abstract at ADS Title: Fine-Scale Magnetic Field in a Sunspot Penumbra and Adjacent Photosphere Authors: Frank, Z. A.; Scharmer, G. B.; Keller, C.; Lundstedt, H. Bibcode: 1991BAAS...23.1052F Altcode: No abstract at ADS Title: Observations of the Birth and Death of Mesogranules Authors: Simon, G. W.; Title, A. M.; Shine, R. A.; Frank, Z.; Muller, R.; Auffret, H. Bibcode: 1991BAAS...23.1034S Altcode: No abstract at ADS Title: Power Spectra of Flows and Magnetic Fields in the Solar Photosphere Authors: Tarbell, T. D.; Slater, G. L.; Frank, Z. A.; Topka, K. P.; Scharmer, G.; Schmidt, W. Bibcode: 1991BAAS...23.1048T Altcode: No abstract at ADS Title: Field Geometry of Sunspots Inferred from Inclination Effects Authors: Title, A. M.; Frank, Z. A.; Shine, R. A.; Tarbell, T. D. Bibcode: 1991BAAS...23R1052T Altcode: No abstract at ADS Title: Sunspot Umbral and Penumbral Oscillations in Hα Authors: Shine, R.; Tarbell, T.; Title, A.; Topka, K.; Frank, Z.; Smith, K. Bibcode: 1991BAAS...23.1033S Altcode: No abstract at ADS Title: Stokes Polarimetry of a Sunspot from the Swedish Solar Observatory at La Palma Authors: Topka, K. P.; Frank, Z. A.; Tarbell, T. D.; Title, A. M.; Scharmer, G. Bibcode: 1991BAAS...23Q1052T Altcode: No abstract at ADS Title: Results from high resolution solar images and spectra obtained at the Pic du Midi Observatory (1986-1990) Authors: Roudier, Th.; Muller, R.; Vigneau, J.; Auffret, H.; Espagnet, O.; Simon, G. W.; Title, A. M.; Frank, Z.; Shine, R. A.; Tarbell, T. D.; Mein, P.; Malherbe, J. M. Bibcode: 1991AdSpR..11e.205R Altcode: 1991AdSpR..11..205R We present an overview of our recent results about solar granulation and mesogranulation, obtained with Pic du Midi observations. These results were obtained during 1986-1990 using image and spectrographic analysis of high spatial resolution data. The study of the solar granulation, with 2 Dim. ``Multichannel Subtractive Double Pass'' (M.S.D.P.) spectra, shows a clear change of the dynamical regime at 3'' (⋍ 2200 km) of the photospheric velocity field when oscillatory components are filtered out.

A three hour movie obtained on film at Pic du Midi Observatory and analyzed at the Lockheed Research Laboratory and the National Solar Observatory (Sacramento Peak) was used to calculate the horizontal flow pattern. The mean lifetime of the diverging areas related to mesogranulation is estimated at 3 hours; these diverging areas are swept by the supergranulation flow towards the supergranule boundary with a mean speed of 0.4 km/s. Title: Generation of Electric Currents and Waves on Magnetic Flux Tubes by Horizontal Velocities in the Photosphere (With 1 Figure) Authors: Tarbell, T. D.; Slater, G. L.; Frank, Z. A.; Shine, R. A.; Topka, K. P. Bibcode: 1991mcch.conf...39T Altcode: No abstract at ADS Title: Generation of Waves and Electric Currents on Magnetic Flux Tubes by Horizontal and Vertical Velocities in the Photosphere Authors: Frank, Z. A.; Shine, R. A.; Slater, G.; Tarbell, T.; Topka, K. Bibcode: 1990BAAS...22..878F Altcode: No abstract at ADS Title: High-Resolution Observations of Emerging Magnetic Fields and Flux Tubes in Active Region Photosphere Authors: Tarbell, T.; Ferguson, S.; Frank, Z.; Shine, R.; Title, A.; Topka, K.; Scharmer, G. Bibcode: 1990IAUS..138..147T Altcode: No abstract at ADS Title: Structure and Evolution of the Large Scale Granulation Authors: Muller, R.; Roudier, Th.; Vigneau, J.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Simon, G. Bibcode: 1990PDHO....7...44M Altcode: 1990dysu.conf...44M; 1990ESPM....6...44M A granulation movie of 3 hours has been performed at the Pic du Midi Observatory on September 20, 1988. Title: Formation of Network Bright Points by Granule Compression Authors: Muller, R.; Roudier, Th.; Vigneau, J.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Simon, G. Bibcode: 1990PDHO....7..150M Altcode: 1990dysu.conf..150M; 1990ESPM....6..150M No abstract at ADS Title: Intial Results of the Lockheed 1989 La Palma Observing Campaign Authors: Topka, K.; Frank, Z.; Shine, R.; Smith, K.; Tarbell, T.; Title, A.; Scharmer, G. Bibcode: 1989BAAS...21.1111T Altcode: No abstract at ADS Title: High - resolution observations of emerging magnetic flux Authors: Tarbell, T. D.; Topka, K.; Ferguson, S.; Frank, Z.; Title, A. M. Bibcode: 1989hsrs.conf..506T Altcode: No abstract at ADS Title: Proper Motion and Lifetime of Mesogranules Authors: Frank, Z.; Muller, R.; Roudier, T.; Vigneau, J.; Shine, R.; Tarbell, T.; Title, A.; Topka, K.; Simon, G. Bibcode: 1989BAAS...21..841F Altcode: No abstract at ADS Title: Short Term Evolution of Fine Scale Magnetic Structures Authors: Topka, K.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Scharmer, G.; Balke, A. Bibcode: 1989BAAS...21..842T Altcode: No abstract at ADS Title: Magnetic Field Inclination in Penumbra of a Round Sunspot Observed at Very High Spatial Resolution Authors: Title, A. M.; Frank, Z. A.; Shine, R. A.; Tarbell, T. D.; Scharmer, G. Bibcode: 1989BAAS...21Q.837T Altcode: No abstract at ADS Title: Observations of Running Penumbral Waves Authors: Shine, R.; Tarbell, T.; Title, A.; Topka, K.; Frank, Z.; Scharmer, G. Bibcode: 1989BAAS...21..837S Altcode: No abstract at ADS Title: Generation of Waves on Magnetic Flux Tubes by Horizontal Velocities in the Photosphere Authors: Tarbell, T. D.; Ferguson, S. H.; Frank, Z. A.; Shine, R. A. Bibcode: 1989BAAS...21..830T Altcode: No abstract at ADS Title: Active Optics, Anisoplanatism, and the Correction of Astronomical Images Authors: Peri, M. L.; Smithson, R. C.; Acton, D. S.; Frank, Z. A.; Title, A. M. Bibcode: 1989ASIC..263...77P Altcode: 1989ssg..conf...77P No abstract at ADS Title: Investigation of active regions at high resolution by balloon flights of the Solar Optical Universal Polarimeter (SOUP) Authors: Tarbell, T.; Frank, Z.; Gilbreth, C.; Shine, R.; Title, A.; Topka, K.; Wolfson, J. Bibcode: 1989dots.work..310T Altcode: SOUP is a versatile, visible-light solar observatory, built for space or balloon flight. It is designed to study magnetic and velocity fields in the solar atmosphere with high spatial resolution and temporal uniformity, which cannot be achieved from the surface of the earth. The SOUP investigation is carried out by the Lockheed Palo Alto Research Laboratory, under contract to NASA's Marshall Space Flight Center. Co-investigators include staff members at a dozen observatories and universities in the U.S. and Europe. The primary objectives of the SOUP experiment are: to measure vector magnetic and velocity fields in the solar atmosphere with much better spatial resolution than can be achieved from the ground; to study the physical processes that store magnetic energy in active regions and the conditions that trigger its release; and to understand how magnetic flux emerges, evolves, combines, and disappears on spatial scales of 400 to 100,000 km. SOUP is designed to study intensity, magnetic, and velocity fields in the photosphere and low chromosphere with 0.5 arcsec resolution, free of atmospheric disturbances. The instrument includes: a 30 cm Cassegrain telescope; an active mirror for image stabilization; broadband film and TV cameras; a birefringent filter, tunable over 5100 to 6600 A with 0.05 A bandpass; a 35 mm film camera and a digital CCD camera behind the filter; and a high-speed digital image processor. Title: Observations of f- and p-mode oscillations of high degree (500 < l < 2500) in quiet and active Sun. Authors: Tarbell, T. D.; Peri, M.; Frank, Z.; Shine, R.; Title, A. M. Bibcode: 1988ESASP.286..315T Altcode: 1988ssls.rept..315T Spectra (l-ν diagrams) from high resolution observations taken at the Vacuum Tower Telescope (NSO/Sunspot) are presented. The raw data are CCD images taken through the SOUP narrowband filter in Fe I 5576 Å. Four filtergrams spaced through the spectral line are combined to form velocity movies. Spectra for 80 minutes of data with 0.5 - 1.5 arcsecond resolution are presented for the entire field-of-view and for quiet and magnetic (plage) subregions. Ridges f and p1 - p5 are evident in velocity spectra, extending to l = 2500(f), l = 1800(p1), and l = 1200(p2). Much less power is seen in the magnetic region than in the quiet sun. Three-dimensional Fourier filtering shows that oscillation velocity amplitude drops sharply at the boundary of the active region for each family of modes considered. Title: High-resolution digital movies of emerging flux and horizontal flows in active regions on the sun Authors: Topka, K.; Ferguson, S.; Frank, Z.; Tarbell, T.; Title, A. Bibcode: 1988fnsm.work..283T Altcode: High-resolution observations of active regions in many wavelength bands obtained at the Vacuum Tower Telescope of NSO/Sunspot (Sacramento Peak) are presented. The SOUP tunable filter, HRSO 1024 x 1024 CCD camera, and a sunspot tracker for image stabilization were used. Subarrays of 512 x 512 pixels were processed digitally and recorded on videodisk in movie format. The movies with 0.5 to 1 arcsecond resolution of the following simultaneous observations were shown: green continuum, longitudinal magnetogram, Doppler velocity, Fe I 5576 A line center, H alpha wings, and H alpha line center. The best set of movies show a 90 x 90 arcsecond field-of-view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Flux emergence is most easily discovered in line center movies: an elongated dark feature appears first, followed soon after by bright points at one or both ends. A brief, strong upflow is seen when the dark feature first appears; downflow in the bright points persists much longer. The magnetic flux appears to increase gradually over this extended period. Some of the flux emergence events were studied in detail, with measurements of horizontal and vertical velocities and magnetic flux versus time within one footpoint of the loop. Title: Observations of photospheric magnetic fields and shear flows in flaring active regions Authors: Tarbell, T.; Ferguson, S.; Frank, Z.; Title, A.; Topka, K. Bibcode: 1988fnsm.work...50T Altcode: Horizontal flows in the photosphere and subsurface convection zone move the footpoints of coronal magnetic field lines. Magnetic energy to power flares can be stored in the corona if the flows drive the fields far from the potential configuration. Videodisk movies were shown with 0.5 to 1 arcsecond resolution of the following simultaneous observations: green continuum, longitudinal magnetogram, Fe I 5576 A line center (mid-photosphere), H alpha wings, and H alpha line center. The movies show a 90 x 90 arcsecond field of view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Magnetic bipoles are emerging over a large area, and the polarities are systematically flowing apart. The horizontal flows were mapped in detail from the continuum movies, and these may be used to predict the future evolution of the region. The horizontal flows are not discernable in H alpha. The H alpha movies strongly suggest reconnection processes in the fibrils joining opposite polarities. When viewed in combination with the magnetic movies, the cause for this evolution is apparent: opposite polarity fields collide and partially cancel, and the fibrils reconnect above the surface. This type of reconnection, driven by subphotospheric flows, complicates the chromospheric and coronal fields, causing visible braiding and twisting of the fibrils. Some of the transient emission events in the fibrils and adjacent plage may also be related. Title: Observations of Granulation in Quiet and Magnetic Sun from the Swedish Solar Observatory on LaPalma Authors: Topka, K.; Ferguson, S.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Wolfson, J.; Scharmer, G.; Brandt, P. Bibcode: 1988BAAS...20S1010T Altcode: No abstract at ADS Title: Solar Activity and Flare Observations from the Swedish Solar Observatory on La Palma Authors: Wolfson, J.; Ferguson, S.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Topka, K.; Scharmer, G.; Brandt, P.; Gurman, J. Bibcode: 1988BAAS...20..978W Altcode: No abstract at ADS Title: Observations of F-and P-Mode Oscillations of High Degree (500< <3500) in Quiet and Active Sun Authors: Peri, M.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A. Bibcode: 1988BAAS...20..702P Altcode: No abstract at ADS Title: Observations of Photospheric Magnetic Fields and Shear Flows in Flaring Active Regions Authors: Tarbell, T.; Ferguson, S.; Frank, Z.; Title, A.; Topka, K. Bibcode: 1988BAAS...20..744T Altcode: No abstract at ADS Title: High-Resolution Digital Movies of Emerging Flux and Horizontal Flows in Active Regions on the Sun Authors: Tarbell, T.; Ferguson, S.; Frank, Z.; Title, A.; Topka, K. Bibcode: 1988BAAS...20..680T Altcode: No abstract at ADS Title: Correlation Lifetimes of Quiet and Magnetic Granulation from the SOUP Instrument on Spacelab 2 Authors: Title, A.; Tarbell, T.; Topka, K.; Acton, L.; Duncan, D.; Ferguson, S.; Finch, M.; Frank, Z.; Kelly, G.; Lindgren, R.; Morrill, M.; Pope, T.; Reeves, R.; Rehse, R.; Shine, R.; Simon, G.; Harvey, J.; Leibacher, J.; Livingston, W.; November, L.; Zirker, J. Bibcode: 1988ApL&C..27..141T Altcode: The time sequences of diffraction limited granulation images obtained by the Solar Optical Universal Polarimeter on Spacelab 2 are presented. The uncorrection autocorrelation limetime in magnetic regions is dominated by the 5-min oscillation. The removal of this oscillation causes the autocorrelation lifetime to increase by more than a factor of 2. The results suggest that a significant fraction of granule lifetimes are terminated by nearby explosions. Horizontal displacements and transverse velocities in the intensity field are measured. Lower limits to the lifetime in the quiet and magnetic sun are set at 440 s and 950 s, respectively. Title: High-Resolution CCD Observations of Doppler and Magnetic Images in the Solar Photosphere Authors: Tarbell, T. D.; Frank, Z. A.; Morrill, M. E.; Shine, R. A.; Topka, K. P.; Title, A. M. Bibcode: 1987BAAS...19.1117T Altcode: No abstract at ADS Title: Sunspot observations from the SOUP instrument on Spacelab 2. Authors: Shine, R. A.; Title, A. M.; Tarbell, T. D.; Acton, L.; Duncan, D.; Ferguson, S. H.; Finch, M.; Frank, Z.; Kelly, G.; Lindgren, R. Bibcode: 1987NASCP2483..133S Altcode: 1987tphr.conf..133S A series of white light images obtained by the SOUP instrument on Spacelab 2 of active region 4682 on August 5, 1985 were analyzed in the area containing sunspots. Although the umbra of the spot is underexposed, the film is well exposed in the penumbral regions. These data were digitally processed to remove noise and to separate p-mode oscillations from low velocity material motions. The results of this preliminary investigation include: (1) proper motion measurements of a radial outflow in the photospheric granulation pattern just outside the penumbra; (2) discovery of occasional bright structures (streakers) that appear to be ejected outward from the penumbra; (3) broad dark clouds moving outward in the penumbra in addition to the well known bright penumbral grains moving inward; (4) apparent extensions and contractions of penumbral filaments over the photosphere; and (5) observation of a faint bubble or loop-like structure which seems to expand from two bright penumbral filaments into the photosphere. Title: First results on quiet and magnetic granulation from SOUP. Authors: Title, A. M.; Tarbell, T. D.; Acton, L.; Duncan, D.; Ferguson, S. H.; Finch, M.; Frank, Z.; Kelly, G.; Lindgren, R.; Morrill, M. Bibcode: 1987NASCP2483...55T Altcode: 1987tphr.conf...55T The flight of Solar Optical Universal Polarimeter (SOUP) on Spacelab 2 allowed the collection of time sequences of diffraction limited (0.5 arc sec) granulation images with excellent pointing (0.003 arc sec) and completely free of the distortion that plagues groundbased images. The p-mode oscillations are clearly seen in the data. Using Fourier transforms in the temporal and spatial domain, it was shown that the p-modes dominate the autocorrelation lifetime in magnetic regions. When these oscillations are removed the autocorrelation lifetime is found to be 500 sec in quiet and 950 sec in magnetic regions. In quiet areas exploding granules are seen to be common. It is speculated that a significant fraction of granule lifetimes are terminated by nearby explosions. Using local correlation tracking techniques it was able to measure horizontal displacements, and thus transverse velocities, in the magnetic field. In quiet sun it is possible to detect both super and mesogranulation. Horizontal velocities are as great as 1000 m/s and the average velocity is 400 m/s. In magnetic regions horizontal velocities are much less, about 100 m/s. Title: White-light movies of the solar photosphere from the soup instrument on spacelab 2 Authors: Title, A. M.; Tarbell, T. D.; Simon, G. W.; Acton, L.; Duncan, D.; Ferguson, S.; Finch, M.; Frank, Z.; Kelly, G.; Lindgren, R.; Morrill, M.; Pope, T.; Reeves, R.; Rehse, R.; Shine, R.; Topka, K.; Harvey, J.; Leibacher, J.; Livingston, W.; November, L. Bibcode: 1986AdSpR...6h.253T Altcode: 1986AdSpR...6..253T We present initial results on solar granulation, pores and sunspots from the white-light films obtained by the Solar Optical Universal Polarimeter (SOUP) instrument on Spacelab 2. SOUP contains a 30-cm Cassegrain telescope, an active secondary mirror for image stabilization, and a white-light optical system with 35-mm film and video cameras. Outputs from the fine guidance servo provided engineering data on the performance of the ESA Instrument Pointing System (IPS). Several hours of movies were taken at various disk and limb positions in quiet and active regions. The images are diffraction-limited at 0.5 arc second resolution and are, of course, free of atmospheric seeing and distortion. Properties of the granulation in magnetic and non-magnetic regions are compared and are found to differ significantly in size, rate of intensity variation, and lifetime. In quiet sun on the order of fifty percent of the area has at least one ``exploding granule'' occurring in it during a 25 minute period. Local correlation tracking has detected several types of transverse flows, including systematic outflow from the penumbral boundary of a spot, motion of penumbral filaments, and cellular flow patterns of supergranular and mesogranular size. Feature tracking has shown that in quiet sun the average granule fragment has a velocity of about one kilometer per second. Title: The helium 10830 angstrom line in early-type stars : an atlas of Fabry-Perot scans. Authors: Meisel, D. D.; Saunders, B. A.; Frank, Z. A.; Packard, M. L. Bibcode: 1982ApJ...263..759M Altcode: Representative profiles of He I 10830 A in 65 early-type (O6-A1) stars over a wide range of luminosity are presented. The atlas scans were obtained using the Vaughan Fabry-Perot interferometer on the C. E. K. Mees 0.6 m and KPNO 0.9 m telescopes and usually cover a range of plus or minus 15 A at 1 A resolution with sampling distances between 0.5 A and 2 A depending on the photometer integration time required to reach reasonable Poisson counting statistics. The majority of the scans show very shallow, broad features which do not agree with plane-parallel NLTE model atmosphere calculations of the 10830 line by Auer and Mihalas (1972). Difficulties connected with previous theoretical studies of this line are briefly discussed, and suggestions for possible future modifications to the theory are made. Title: He I lambda 10830 in some O6 - B3 III, IV, V stars. Authors: Frank, Z.; Meisel, D. D.; Saunders, B. Bibcode: 1980BAAS...12Q.751F Altcode: No abstract at ADS Title: Very wideband corrugated horns. Authors: Frank, Z. Bibcode: 1975ElL....11..131F Altcode: An expression for the input impedance of a short-circuited, linearly-tapered transmission line is derived. The use of tapered slots in a corrugated horn is proposed as a means of broadening their bandwidth to greater than 3:1. Test results are presented for an experimental horn operating over the full 7.5-18 GHz range of DR14 waveguide.