Author name code: harra ADS astronomy entries on 2022-09-14 author:"Harra, Louise K." ------------------------------------------------------------------------ Title: What drives decayless kink oscillations in active region coronal loops on the Sun? Authors: Mandal, Sudip; Chitta, Lakshmi P.; Antolin, Patrick; Peter, Hardi; Solanki, Sami K.; Auchère, Frédéric; Berghmans, David; Zhukov, Andrei N.; Teriaca, Luca; Cuadrado, Regina A.; Schühle, Udo; Parenti, Susanna; Buchlin, Éric; Harra, Louise; Verbeeck, Cis; Kraaikamp, Emil; Long, David M.; Rodriguez, Luciano; Pelouze, Gabriel; Schwanitz, Conrad; Barczynski, Krzysztof; Smith, Phil J. Bibcode: 2022arXiv220904251M Altcode: We study here the phenomena of decayless kink oscillations in a system of active region (AR) coronal loops. Using high resolution observations from two different instruments, namely the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we follow these AR loops for an hour each on three consecutive days. Our results show significantly more resolved decayless waves in the higher-resolution EUI data compared with the AIA data. Furthermore, the same system of loops exhibits many of these decayless oscillations on Day-2, while on Day-3, we detect very few oscillations and on Day-1, we find none at all. Analysis of photospheric magnetic field data reveals that at most times, these loops were rooted in sunspots, where supergranular flows are generally absent. This suggests that supergranular flows, which are often invoked as drivers of decayless waves, are not necessarily driving such oscillations in our observations. Similarly, our findings also cast doubt on other possible drivers of these waves, such as a transient driver or mode conversion of longitudinal waves near the loop footpoints. In conclusion, through our analysis we find that none of the commonly suspected sources proposed to drive decayless oscillations in active region loops seems to be operating in this event and hence, the search for that elusive wave driver needs to continue. Title: Spatial distribution of jets in solar active regions Authors: Odermatt, J.; Barczynski, K.; Harra, L. K.; Schwanitz, C.; Krucker, S. Bibcode: 2022A&A...665A..29O Altcode: 2022arXiv220709923O Context. Solar active regions are known to have jets. These jets are associated with heating and the release of particles into the solar wind.
Aims: Our aim is to understand the spatial distribution of coronal jets within active regions to understand if there is a preferential location for them to occur.
Methods: We analysed five active regions using Solar Dynamics Observatory Atmospheric Imaging Assembly data over a period of 2-3.5 days when the active regions were close to disk centre. Each active region had a different age, magnetic field strength, and topology. We developed a methodology for determining the position and length of the jets.
Results: Jets are observed more frequently at the edges of the active regions and are more densely located around a strong leading sunspot. The number of coronal jets for our active regions is dependent on the age of the active region. The older active regions produce more jets than younger ones. Jets were observed dominantly at the edges of the active regions, and not as frequently in the centre. The number of jets is independent of the average unsigned magnetic field and total flux density in the whole active region. The jets are located around the edges of the strong leading sunspot. Title: The Solaris Solar Polar MIDEX-Class Mission Concept: Revealing the Mysteries of the Sun's Poles Authors: Hassler, Donald M.; Harra, Louise K.; Gibson, Sarah; Thompson, Barbara; Gusain, Sanjay; Berghmans, David; Linker, Jon; Basu, Sarbani; Featherstone, Nicholas; Hoeksema, J. Todd; Viall, Nicholeen; Newmark, Jeffrey; Munoz-Jaramillo, Andres; Upton, Lisa A. Bibcode: 2022cosp...44.1528H Altcode: Solaris is an exciting, innovative & bold mission of discovery to reveal the mysteries of the Sun's poles. Solaris was selected for Phase A development as part of NASA's MIDEX program. Solaris builds upon the legacy of Ulysses, which flew over the solar poles, but Solaris provides an entirely new feature remote sensing, or IMAGING. Solaris will be the first mission to image the poles of the Sun from ~75 degrees latitude and provide new insight into the workings of the solar dynamo and the solar cycle, which are at the foundation of our understanding of space weather and space climate. Solaris will also provide enabling observations for improved space weather research, modeling and prediction with time series of polar magnetograms and views of the ecliptic from above, providing a unique view of the corona, coronal dynamics, and CME eruption. To reach the Sun's poles, Solaris will first travel to Jupiter, and use Jupiter's gravity to slingshot out of the ecliptic plane, and fly over the Sun's poles at ~75 degrees latitude. Just as our understanding of Jupiter & Saturn were revolutionized by polar observations from Juno and Cassini, our understanding of the Sun will be revolutionized by Solaris. Title: Plasma flows in different magnetic environments on the Sun Authors: Harra, Louise K. Bibcode: 2022cosp...44.2408H Altcode: The Sun, as a magnetic star, has dynamics and complex structures on all scales. There are flows throughout the solar atmosphere from the surface to the outer solar atmosphere (and into the solar wind). In this review, we will discuss from the smallest scale flows seen, to the most dramatic flows in coronal mass ejections. The smallest scale phenomena such as jets, plumes and small brightenings such as those seen in the Solar Orbiter 'campfires' all have possibilities to flow into the solar wind. The latest results from Parker Solar Probe has provided tantalising predictions of when the magnetic switchbacks seen in the solar wind originate - on the network boundaries where many of these small-scale flows are seen. Moving to the large size scale flows, with the large flares, and coronal mass ejections, the flows start in the pre-trigger phase on a small size scale, and expand across the Sun, creating a huge impact in the solar wind. The current status will be reviewed. Title: A spectral solar irradiance monitor (SoSpIM) on the JAXA Solar-C (EUVST) space mission Authors: Harra, Louise K.; Watanabe, Kyoko; Haberreiter, Margit; Hori, Tomoaki; Hara, Hirohisa; Kretzschmar, Matthieu; Woods, Thomas; Shimizu, Toshifumi; Krucker, Samuel; Berghmans, David; Jin, Hidekatsu; Dominique, Marie; Eparvier, Francis G.; Gissot, Samuel; Leng Yeo, Kok; Pfiffner, Dany; Milligan, Ryan; Thiemann, Edward; Miyoshi, Yoshizumi; Imada, Shinsuke; Kawate, Tomoko; Chamberlin, Phillip; Rozanov, Eugene; Silvio Koller, -.; Barczynski, Krzysztof; Nozomu; Nishitani; Ieda, Akimasa; Langer, Patrick; Meier, Leandro; Tye, Daniel; Alberti, Andrea Bibcode: 2022cosp...44..834H Altcode: The JAXA Solar-C (EUVST) mission (Shimizu et al., 2020) is designed to comprehensively understand how mass and energy are transferred throughout the solar atmosphere. The EUV High-Throughput Spectroscopic Telescope (EUVST) onboard does this by observing all the temperature regimes of the atmosphere from the chromosphere to the corona simultaneously. To enhance the EUVST scientific capabilities, there will be a Solar Spectral Irradiance Monitor (SoSpIM). SoSpIM will work hand-in-hand scientifically with EUVST, by providing the full Sun irradiance at sub-second time cadence combined with the spatially resolved spectroscopy from EUVST. The SoSPIM instrument will specifically address two aspects. These are: · Understand how the solar atmosphere becomes unstable, releasing the energy that drives solar flares - achieved through probing fast time cadence solar flare variations. · Measuring solar irradiance that impacts the Earth's thermosphere and the mesosphere, linking to spatially resolved measurements of the solar atmosphere with EUVST. SoSpIM will provide high time resolution measurements in 2 channels (a) in the corona through channel 1 (EUV) and (b) in the lower atmosphere through channel 2 (Lyman alpha). Each channel impacts different layers of the Earth's atmosphere. Title: How Can Solar-C/SOSPIM Contribute to the Understanding of Quasi-Periodic Pulsations in Solar Flares? Authors: Dominique, Marie; Harra, Louise K.; Watanabe, Kyoko; Hara, Hirohisa; Zhukov, Andrei; Shimizu, Toshifumi; Berghmans, David; Dolla, Laurent; Gissot, Samuel; Pfiffner, Dany; Imada, Shinsuke; Silvio Koller, -.; Meier, Leandro; Tye, Daniel; Alberti, Andrea Bibcode: 2022cosp...44.2524D Altcode: Quasi-periodic pulsations (QPPs) refer to nearly-periodic oscillations that are often observed in irradiance time series during solar flares and have also been reported in several stellar flares. In the last years, several statistical studies based on Soft X-ray measurements have reached the conclusion that QPPs are present in most solar flares of class M and above. Still, as of today, we are still unsure of what causes QPPs. Several models could explain the presence of QPPs with periods matching the ones observed. More detailed analysis of the observational signatures of QPPs might help determine which of those models are actually playing a role in the generation of QPPs. However, as QPPs is a small timescale process (the period of QPPs is often reported to be less than a minute), such an analysis requires instruments with a good signal-to-noise and high sampling rate. In this context, the spectral solar irradiance monitor SOSPIM, that will be part of the JAXA SOLAR C mission and that will complement the EUVST spectrograph measurements, could be a valuable asset. SOSPIM will observe the solar chromosphere and corona in the Lyman-alpha and EUV spectral ranges at high cadence. In this presentation, we review the current knowledge of QPPs and describe what could be the contribution of SOSPIM to push their understanding one step forward. Title: Heating during small solar flares with Solar Orbiter STIX, Hinode and SDO. Authors: Harra, Louise K.; Reeves, Kathy; Krucker, Sam; Barczynski, Krzysztof; Battaglia, Andrea; Collier, Hannah Bibcode: 2022cosp...44.2525H Altcode: One of the key aspects of solar flares is how, where and how fast plasma is heated. Spectroscopic observations are constrained by the duration it takes to build up an image and hence the time resolution is often of the order of 5 minutes during a flare. To obtain higher cadence spectroscopic information, it is also possible to use the wide slot (260") - or 'overlappogram' data. An observing campaign (HOP361) was carried out in October using Hinode EIS, XRT and coordinating with Solar Orbiter STIX. The campaign was carried out at high time cadence and was telemetry intensive. SDO is also of key interest to these observations. On the 8th October, a B2 classfication flare took place, and was observed by all instruments. The EIS 'overlappogram' allows high time cadence observations (10 secs) of the whole active region. During this flare, it is possible to extract information on the hot plasma from Fe XXIV, STIX and XRT. There was a smaller flare which wasn't registered by GOES that followed, that provides a contrast example that doesn't show clear hot emission. Title: Automatic detection of small-scale EUV brightenings observed by the Solar Orbiter/EUI Authors: Alipour, N.; Safari, H.; Verbeeck, C.; Berghmans, D.; Auchère, F.; Chitta, L. P.; Antolin, P.; Barczynski, K.; Buchlin, É.; Aznar Cuadrado, R.; Dolla, L.; Georgoulis, M. K.; Gissot, S.; Harra, L.; Katsiyannis, A. C.; Long, D. M.; Mandal, S.; Parenti, S.; Podladchikova, O.; Petrova, E.; Soubrié, É.; Schühle, U.; Schwanitz, C.; Teriaca, L.; West, M. J.; Zhukov, A. N. Bibcode: 2022A&A...663A.128A Altcode: 2022arXiv220404027A Context. Accurate detections of frequent small-scale extreme ultraviolet (EUV) brightenings are essential to the investigation of the physical processes heating the corona.
Aims: We detected small-scale brightenings, termed campfires, using their morphological and intensity structures as observed in coronal EUV imaging observations for statistical analysis.
Methods: We applied a method based on Zernike moments and a support vector machine (SVM) classifier to automatically identify and track campfires observed by Solar Orbiter/Extreme Ultraviolet Imager (EUI) and Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA).
Results: This method detected 8678 campfires (with length scales between 400 km and 4000 km) from a sequence of 50 High Resolution EUV telescope (HRIEUV) 174 Å images. From 21 near co-temporal AIA images covering the same field of view as EUI, we found 1131 campfires, 58% of which were also detected in HRIEUV images. In contrast, about 16% of campfires recognized in HRIEUV were detected by AIA. We obtain a campfire birthrate of 2 × 10−16 m−2 s−1. About 40% of campfires show a duration longer than 5 s, having been observed in at least two HRIEUV images. We find that 27% of campfires were found in coronal bright points and the remaining 73% have occurred out of coronal bright points. We detected 23 EUI campfires with a duration greater than 245 s. We found that about 80% of campfires are formed at supergranular boundaries, and the features with the highest total intensities are generated at network junctions and intense H I Lyman-α emission regions observed by EUI/HRILya. The probability distribution functions for the total intensity, peak intensity, and projected area of campfires follow a power law behavior with absolute indices between 2 and 3. This self-similar behavior is a possible signature of self-organization, or even self-organized criticality, in the campfire formation process.

Supplementary material (S1-S3) is available at https://www.aanda.org Title: Searching for a Solar Source of Magnetic-Field Switchbacks in Parker Solar Probe's First Encounter Authors: de Pablos, D.; Samanta, T.; Badman, S. T.; Schwanitz, C.; Bahauddin, S. M.; Harra, L. K.; Petrie, G.; Mac Cormack, C.; Mandrini, C. H.; Raouafi, N. E.; Martinez Pillet, V.; Velli, M. Bibcode: 2022SoPh..297...90D Altcode: Parker Solar Probe observations show ubiquitous magnetic-field reversals closer to the Sun, often referred to as "switchbacks". The switchbacks have been observed before in the solar wind near 1 AU and beyond, but their occurrence was historically rare. PSP measurements below ∼ 0.2 AU show that switchbacks are, however, the most prominent structures in the "young" solar wind. In this work, we analyze remote-sensing observations of a small equatorial coronal hole to which PSP was connected during the perihelion of Encounter 1. We investigate whether some of the switchbacks captured during the encounter were of coronal origin by correlating common switchback in situ signatures with remote observations of their expected coronal footpoint. We find strong evidence that timescales present in the corona are relevant to the outflowing, switchback-filled solar wind, as illustrated by strong linear correlation. We also determine that spatial analysis of the observed region is optimal, as the implied average solar-wind speed more closely matches that observed by PSP at the time. We observe that hemispherical structures are strongly correlated with the radial proton velocity and the mass flux in the solar wind. The above findings suggest that a subpopulation of the switchbacks are seeded at the corona and travel into interplanetary space. Title: Constraining Global Coronal Models with Multiple Independent Observables Authors: Badman, Samuel T.; Brooks, David H.; Poirier, Nicolas; Warren, Harry P.; Petrie, Gordon; Rouillard, Alexis P.; Nick Arge, C.; Bale, Stuart D.; de Pablos Agüero, Diego; Harra, Louise; Jones, Shaela I.; Kouloumvakos, Athanasios; Riley, Pete; Panasenco, Olga; Velli, Marco; Wallace, Samantha Bibcode: 2022ApJ...932..135B Altcode: 2022arXiv220111818B Global coronal models seek to produce an accurate physical representation of the Sun's atmosphere that can be used, for example, to drive space-weather models. Assessing their accuracy is a complex task, and there are multiple observational pathways to provide constraints and tune model parameters. Here, we combine several such independent constraints, defining a model-agnostic framework for standardized comparison. We require models to predict the distribution of coronal holes at the photosphere, and neutral line topology at the model's outer boundary. We compare these predictions to extreme-ultraviolet (EUV) observations of coronal hole locations, white-light Carrington maps of the streamer belt, and the magnetic sector structure measured in situ by Parker Solar Probe and 1 au spacecraft. We study these metrics for potential field source surface (PFSS) models as a function of source surface height and magnetogram choice, as well as comparing to the more physical Wang-Sheeley-Arge (WSA) and the Magnetohydrodynamic Algorithm outside a Sphere (MAS) models. We find that simultaneous optimization of PFSS models to all three metrics is not currently possible, implying a trade-off between the quality of representation of coronal holes and streamer belt topology. WSA and MAS results show the additional physics that they include address this by flattening the streamer belt while maintaining coronal hole sizes, with MAS also improving coronal hole representation relative to WSA. We conclude that this framework is highly useful for inter- and intra-model comparisons. Integral to the framework is the standardization of observables required of each model, evaluating different model aspects. Title: Observation of Magnetic Switchback in the Solar Corona Authors: Telloni, Daniele; Zank, Gary P.; Stangalini, Marco; Downs, Cooper; Liang, Haoming; Nakanotani, Masaru; Andretta, Vincenzo; Antonucci, Ester; Sorriso-Valvo, Luca; Adhikari, Laxman; Zhao, Lingling; Marino, Raffaele; Susino, Roberto; Grimani, Catia; Fabi, Michele; D'Amicis, Raffaella; Perrone, Denise; Bruno, Roberto; Carbone, Francesco; Mancuso, Salvatore; Romoli, Marco; Da Deppo, Vania; Fineschi, Silvano; Heinzel, Petr; Moses, John D.; Naletto, Giampiero; Nicolini, Gianalfredo; Spadaro, Daniele; Teriaca, Luca; Frassati, Federica; Jerse, Giovanna; Landini, Federico; Pancrazzi, Maurizio; Russano, Giuliana; Sasso, Clementina; Berghmans, David; Auchère, Frédéric; Aznar Cuadrado, Regina; Chitta, Lakshmi P.; Harra, Louise; Kraaikamp, Emil; Long, David M.; Mandal, Sudip; Parenti, Susanna; Pelouze, Gabriel; Peter, Hardi; Rodriguez, Luciano; Schühle, Udo; Schwanitz, Conrad; Smith, Phil J.; Verbeeck, Cis; Zhukov, Andrei N. Bibcode: 2022arXiv220603090T Altcode: Switchbacks are sudden, large radial deflections of the solar wind magnetic field, widely revealed in interplanetary space by the Parker Solar Probe. The switchbacks' formation mechanism and sources are still unresolved, although candidate mechanisms include Alfvénic turbulence, shear-driven Kelvin-Helmholtz instabilities, interchange reconnection, and geometrical effects related to the Parker spiral. This Letter presents observations from the Metis coronagraph onboard Solar Orbiter of a single large propagating S-shaped vortex, interpreted as first evidence of a switchback in the solar corona. It originated above an active region with the related loop system bounded by open-field regions to the East and West. Observations, modeling, and theory provide strong arguments in favor of the interchange reconnection origin of switchbacks. Metis measurements suggest that the initiation of the switchback may also be an indicator of the origin of slow solar wind. Title: Stereoscopy of extreme UV quiet Sun brightenings observed by Solar Orbiter/EUI Authors: Zhukov, A. N.; Mierla, M.; Auchère, F.; Gissot, S.; Rodriguez, L.; Soubrié, E.; Thompson, W. T.; Inhester, B.; Nicula, B.; Antolin, P.; Parenti, S.; Buchlin, É.; Barczynski, K.; Verbeeck, C.; Kraaikamp, E.; Smith, P. J.; Stegen, K.; Dolla, L.; Harra, L.; Long, D. M.; Schühle, U.; Podladchikova, O.; Aznar Cuadrado, R.; Teriaca, L.; Haberreiter, M.; Katsiyannis, A. C.; Rochus, P.; Halain, J. -P.; Jacques, L.; Berghmans, D. Bibcode: 2021A&A...656A..35Z Altcode: 2021arXiv210902169Z Context. The three-dimensional fine structure of the solar atmosphere is still not fully understood as most of the available observations are taken from a single vantage point.
Aims: The goal of the paper is to study the three-dimensional distribution of the small-scale brightening events ("campfires") discovered in the extreme-UV quiet Sun by the Extreme Ultraviolet Imager (EUI) aboard Solar Orbiter.
Methods: We used a first commissioning data set acquired by the EUI's High Resolution EUV telescope on 30 May 2020 in the 174 Å passband and we combined it with simultaneous data taken by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory in a similar 171 Å passband. The two-pixel spatial resolution of the two telescopes is 400 km and 880 km, respectively, which is sufficient to identify the campfires in both data sets. The two spacecraft had an angular separation of around 31.5° (essentially in heliographic longitude), which allowed for the three-dimensional reconstruction of the campfire position. These observations represent the first time that stereoscopy was achieved for brightenings at such a small scale. Manual and automatic triangulation methods were used to characterize the campfire data.
Results: The height of the campfires is located between 1000 km and 5000 km above the photosphere and we find a good agreement between the manual and automatic methods. The internal structure of campfires is mostly unresolved by AIA; however, for a particularly large campfire, we were able to triangulate a few pixels, which are all in a narrow range between 2500 and 4500 km.
Conclusions: We conclude that the low height of EUI campfires suggests that they belong to the previously unresolved fine structure of the transition region and low corona of the quiet Sun. They are probably apexes of small-scale dynamic loops heated internally to coronal temperatures. This work demonstrates that high-resolution stereoscopy of structures in the solar atmosphere has become feasible. Title: Linking solar activity to solar wind: challenges and future observations. Authors: Harra, Louise Bibcode: 2021AGUFMSH15D2052H Altcode: The current era of solar physics missions is opening up new ways to view the Sun, from the sources of solar wind, to direct measurements at varying distances from the Sun. Parker Solar Probe (PSP) has already reached closer to the Sun than ever before. Solar Orbiter will start its nominal science mission in December 2021. In this review, I will discuss the activity on the Sun, from the smallest scales, that could be contributing to the solar wind. I will discuss the attempts made to link remote sensing and in-situ observations, and the challenges that are faced. Spectroscopic observations hold particular value due to the measurements of speeds and abundances, but have a small field of view. Combined with imaging data and modelling efforts, understanding what could flow into the solar wind is a key task for the solar and heliospheric communities in the next years. Higher resolutions, and new datatypes open new ways to explore the sources of the solar wind. Title: Probing Upflowing Regions in the Quiet Sun and Coronal Holes Authors: Schwanitz, Conrad; Harra, Louise; Raouafi, Nour E.; Sterling, Alphonse C.; Moreno Vacas, Alejandro; del Toro Iniesta, Jose Carlos; Orozco Suárez, David; Hara, Hirohisa Bibcode: 2021SoPh..296..175S Altcode: 2021arXiv211012753S Recent observations from Parker Solar Probe have revealed that the solar wind has a highly variable structure. How this complex behaviour is formed in the solar corona is not yet known, since it requires omnipresent fluctuations, which constantly emit material to feed the wind. In this article we analyse 14 upflow regions in the solar corona to find potential sources for plasma flow. The upflow regions are derived from spectroscopic data from the EUV Imaging Spectrometer (EIS) on board Hinode determining their Doppler velocity and defining regions which have blueshifts stronger than −6 kms−1. To identify the sources of these blueshift data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI), on board the Solar Dynamics Observatory (SDO), and the X-ray Telescope (XRT), on board Hinode, are used. The analysis reveals that only 5 out of 14 upflows are associated with frequent transients, like obvious jets or bright points. In contrast to that, seven events are associated with small-scale features, which show a large variety of dynamics. Some resemble small bright points, while others show an eruptive nature, all of which are faint and only live for a few minutes; we cannot rule out that several of these sources may be fainter and, hence, less obvious jets. Since the complex structure of the solar wind is known, this suggests that new sources have to be considered or better methods used to analyse the known sources. This work shows that small and frequent features, which were previously neglected, can cause strong upflows in the solar corona. These results emphasise the importance of the first observations from the Extreme-Ultraviolet Imager (EUI) on board Solar Orbiter, which revealed complex small-scale coronal structures. Title: How Can Solar-C/SOSPIM Contribute to the Understanding of Quasi-Periodic Pulsations in Solar Flares? Authors: Dominique, Marie; Dolla, Laurent; Zhukov, Andrei; Alberti, Andrea; Berghmans, David; Gissot, Samuel; Hara, Hirohisa; Harra, Louise; Imada, Shinsuke; Koller, Silvio; Meier, Leandro; Pfiffner, Daniel; Shimizu, Toshifumi; Tye, Daniel; Watanabe, Kyoko Bibcode: 2021AGUFMSH25E2124D Altcode: Quasi-periodic pulsations (QPPs) refer to nearly-periodic oscillations that are often observed in irradiance time series during solar flares and have also been reported in several stellar flares. In the last years, several statistical studies based on Soft X-ray measurements have reached the conclusion that QPPs are present in most solar flares of class M and above. Still, the mechanism at the origin of QPPs is under debate. Are they caused by waves or periodic fluctuations of the magnetic reconnection driving the flare? Analyzing the characteristics of QPPs and their evolution during the flare could help identifying their origin. However, QPPs sometimes exhibit very different periodicities, and do not always happen during the same phase of the flare. All this could point to the coexistence of QPPs with different origin mechanism, and indicates the need for more observations. In this context, the spectral solar irradiance monitor SOSPIM, that will be part of the JAXA SOLAR C mission and that will complement the EUVST spectrograph measurements, could be a valuable asset. SOSPIM will observe the solar chromosphere and corona in the Lyman-alpha and EUV spectral ranges at high cadence. In this presentation, we review the current knowledge of QPPs and describe what could be the contribution of SOSPIM to push their understanding one step forward. Title: Full Vector Velocity Reconstruction Using Solar Orbiter Doppler Map Observations. Authors: Podladchikova, Olena; Harra, Louise; Barczynski, Krzysztof; Mandrini, Cristina; Auchere, F.; Berghmans, David; Buchlin, Eric; Dolla, Laurent; Mierla, Marilena; Parenti, Susanna; Rodriguez, Luciano Bibcode: 2021AGUFMNG35B0432P Altcode: The Solar Orbiter mission opens up opportunities forthe combined analysis of measurements obtained by solar imagers and spectrometers. For the first time, different space spectrometerswill be located at wide angles to each other, allowing three-dimensional (3D) spectroscopy of the solar atmosphere.The aim of this work is to prepare the methodology to facilitate the reconstruction of 3D vector velocities from two stereoscopicLOS Doppler velocity measurements using the Spectral Imaging of the Coronal Environment (SPICE) on board the Solar Orbiter andthe near-Earth spectrometers, while widely separated in space. We develop the methodology using the libraries designed earlier for the STEREO mission but applied to spectroscopicdata from the Hinode mission and the Solar Dynamics Observatory. We use well-known methods of static and dynamic solar rotationstereoscopy and the methods of EUV stereoscopic triangulation for optically-thin coronal EUV plasma emissions. We develop new algorithms using analytical geometry in space to determine the 3D velocity in coronal loops. We demonstrate our approach with the reconstruction of 3D velocity vectors in plasma flows along "open" and "closed"magnetic loops. This technique will be applied first to an actual situation of two spacecraft at different separations with spectrometers onboard (SPICE versus the Interface Region Imaging Spectrograph (IRIS) and Hinode imaging spectrometer) during the Solar Orbiternominal phase. We summarise how these observations can be coordinated. Title: Stereoscopy of extreme UV quiet Sun brightenings observed by Solar Orbiter/EUI Authors: Zhukov, Andrei; Mierla, Marilena; Auchere, F.; Gissot, Samuel; Rodriguez, Luciano; Soubrie, Elie; Thompson, William; Inhester, Bernd; Nicula, Bogdan; Antolin, Patrick; Parenti, Susanna; Buchlin, Eric; Barczynski, Krzysztof; Verbeeck, Cis; Kraaikamp, Emil; Smith, Philip; Stegen, Koen; Dolla, Laurent; Harra, Louise; Long, David; Schuhle, Udo; Podladchikova, Olena; Aznar Cuadrado, Regina; Teriaca, Luca; Haberreiter, Margit; Katsiyannis, Athanassios; Rochus, Pierre; Halain, Jean-Philippe; Jacques, Lionel; Berghmans, David Bibcode: 2021AGUFMSH21A..03Z Altcode: We study the three-dimensional distribution of small-scale brightening events (campfires) discovered in the extreme-ultraviolet (EUV) quiet Sun by the EUI telescope onboard the Solar Orbiter mission. We use one of the first commissioning data sets acquired by the HRI_EUV telescope of EUI on 2020 May 30 in the 174 A passband, combined with the simultaneous SDO/AIA dataset taken in the very similar 171 A passband. The spatial resolution of the two telescopes is sufficient to identify the campfires in both datasets. The angular separation between the two spacecraft of around 31.5 degrees allowed for the three-dimensional reconstruction of the position of campfires. This is the first time that stereoscopy was achieved for structures at such a small scale. Manual and automatic triangulation methods were used. The height of campfires is between 1000 km and 5000 km above the photosphere, and there is a good agreement between the results of manual and automatic methods. The internal structure of campfires is mostly not resolved by AIA, but for a large campfire we could triangulate a few pixels, which are all in a narrow height range between 2500 and 4500 km. The low height of campfires suggests that they belong to the previously unresolved fine structure of the transition region and low corona of the quiet Sun. They are probably apexes of small-scale dynamic loops internally heated to coronal temperatures. This work demonstrates that high-resolution stereoscopy of structures in the solar atmosphere has become possible. Title: Extreme-UV quiet Sun brightenings observed by the Solar Orbiter/EUI Authors: Berghmans, D.; Auchère, F.; Long, D. M.; Soubrié, E.; Mierla, M.; Zhukov, A. N.; Schühle, U.; Antolin, P.; Harra, L.; Parenti, S.; Podladchikova, O.; Aznar Cuadrado, R.; Buchlin, É.; Dolla, L.; Verbeeck, C.; Gissot, S.; Teriaca, L.; Haberreiter, M.; Katsiyannis, A. C.; Rodriguez, L.; Kraaikamp, E.; Smith, P. J.; Stegen, K.; Rochus, P.; Halain, J. P.; Jacques, L.; Thompson, W. T.; Inhester, B. Bibcode: 2021A&A...656L...4B Altcode: 2021arXiv210403382B Context. The heating of the solar corona by small heating events requires an increasing number of such events at progressively smaller scales, with the bulk of the heating occurring at scales that are currently unresolved.
Aims: The goal of this work is to study the smallest brightening events observed in the extreme-UV quiet Sun.
Methods: We used commissioning data taken by the Extreme Ultraviolet Imager (EUI) on board the recently launched Solar Orbiter mission. On 30 May 2020, the EUI was situated at 0.556 AU from the Sun. Its High Resolution EUV telescope (HRIEUV, 17.4 nm passband) reached an exceptionally high two-pixel spatial resolution of 400 km. The size and duration of small-scale structures was determined by the HRIEUV data, while their height was estimated from triangulation with simultaneous images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory mission. This is the first stereoscopy of small-scale brightenings at high resolution.
Results: We observed small localised brightenings, also known as `campfires', in a quiet Sun region with length scales between 400 km and 4000 km and durations between 10 s and 200 s. The smallest and weakest of these HRIEUV brightenings have not been previously observed. Simultaneous observations from the EUI High-resolution Lyman-α telescope (HRILya) do not show localised brightening events, but the locations of the HRIEUV events clearly correspond to the chromospheric network. Comparisons with simultaneous AIA images shows that most events can also be identified in the 17.1 nm, 19.3 nm, 21.1 nm, and 30.4 nm pass-bands of AIA, although they appear weaker and blurred. Our differential emission measure analysis indicated coronal temperatures peaking at log T ≈ 6.1 − 6.15. We determined the height for a few of these campfires to be between 1000 and 5000 km above the photosphere.
Conclusions: We find that `campfires' are mostly coronal in nature and rooted in the magnetic flux concentrations of the chromospheric network. We interpret these events as a new extension to the flare-microflare-nanoflare family. Given their low height, the EUI `campfires' could stand as a new element of the fine structure of the transition region-low corona, that is, as apexes of small-scale loops that undergo internal heating all the way up to coronal temperatures. Title: First observations from the SPICE EUV spectrometer on Solar Orbiter Authors: Fludra, A.; Caldwell, M.; Giunta, A.; Grundy, T.; Guest, S.; Leeks, S.; Sidher, S.; Auchère, F.; Carlsson, M.; Hassler, D.; Peter, H.; Aznar Cuadrado, R.; Buchlin, É.; Caminade, S.; DeForest, C.; Fredvik, T.; Haberreiter, M.; Harra, L.; Janvier, M.; Kucera, T.; Müller, D.; Parenti, S.; Schmutz, W.; Schühle, U.; Solanki, S. K.; Teriaca, L.; Thompson, W. T.; Tustain, S.; Williams, D.; Young, P. R.; Chitta, L. P. Bibcode: 2021A&A...656A..38F Altcode: 2021arXiv211011252F
Aims: We present first science observations taken during the commissioning activities of the Spectral Imaging of the Coronal Environment (SPICE) instrument on the ESA/NASA Solar Orbiter mission. SPICE is a high-resolution imaging spectrometer operating at extreme ultraviolet (EUV) wavelengths. In this paper we illustrate the possible types of observations to give prospective users a better understanding of the science capabilities of SPICE.
Methods: We have reviewed the data obtained by SPICE between April and June 2020 and selected representative results obtained with different slits and a range of exposure times between 5 s and 180 s. Standard instrumental corrections have been applied to the raw data.
Results: The paper discusses the first observations of the Sun on different targets and presents an example of the full spectra from the quiet Sun, identifying over 40 spectral lines from neutral hydrogen and ions of carbon, oxygen, nitrogen, neon, sulphur, magnesium, and iron. These lines cover the temperature range between 20 000 K and 1 million K (10 MK in flares), providing slices of the Sun's atmosphere in narrow temperature intervals. We provide a list of count rates for the 23 brightest spectral lines. We show examples of raster images of the quiet Sun in several strong transition region lines, where we have found unusually bright, compact structures in the quiet Sun network, with extreme intensities up to 25 times greater than the average intensity across the image. The lifetimes of these structures can exceed 2.5 hours. We identify them as a transition region signature of coronal bright points and compare their areas and intensity enhancements. We also show the first above-limb measurements with SPICE above the polar limb in C III, O VI, and Ne VIII lines, and far off limb measurements in the equatorial plane in Mg IX, Ne VIII, and O VI lines. We discuss the potential to use abundance diagnostics methods to study the variability of the elemental composition that can be compared with in situ measurements to help confirm the magnetic connection between the spacecraft location and the Sun's surface, and locate the sources of the solar wind.
Conclusions: The SPICE instrument successfully performs measurements of EUV spectra and raster images that will make vital contributions to the scientific success of the Solar Orbiter mission. Title: Stereoscopic measurements of coronal Doppler velocities Authors: Podladchikova, O.; Harra, L.; Barczynski, K.; Mandrini, C. H.; Auchère, F.; Berghmans, D.; Buchlin, É.; Dolla, L.; Mierla, M.; Parenti, S.; Rodriguez, L. Bibcode: 2021A&A...655A..57P Altcode: 2021arXiv210802280P Context. The Solar Orbiter mission, with an orbit outside the Sun-Earth line and leaving the ecliptic plane, opens up opportunities for the combined analysis of measurements obtained by solar imagers and spectrometers. For the first time different space spectrometers will be located at wide angles to each other, allowing three-dimensional (3D) spectroscopy of the solar atmosphere.
Aims: The aim of this work is to prepare a methodology to facilitate the reconstruction of 3D vector velocities from two stereoscopic line of sight (LOS) Doppler velocity measurements using the Spectral Imaging of the Coronal Environment (SPICE) on board the Solar Orbiter and the near-Earth spectrometers, while widely separated in space.
Methods: We developed the methodology using the libraries designed earlier for the STEREO mission, but applied to spectroscopic data from the Hinode mission and the Solar Dynamics Observatory. We used well-known methods of static and dynamic solar rotation stereoscopy and the methods of extreme ultraviolet (EUV) stereoscopic triangulation for optically thin coronal EUV plasma emissions. We developed new algorithms using analytical geometry in space to determine the 3D velocity in coronal loops.
Results: We demonstrate our approach with the reconstruction of 3D velocity vectors in plasma flows along `open' and `closed' magnetic loops. This technique will be applied to an actual situation of two spacecraft at different separations with spectrometers on board during the Solar Orbiter nominal phase: SPICE versus the Interface Region Imaging Spectrograph (IRIS) and Hinode imaging spectrometer. We summarise how these observations can be coordinated.

Movies associated to Fig. 1 are available at https://www.aanda.org Title: The Formation and Lifetime of Outflows in a Solar Active Region Authors: Brooks, David H.; Harra, Louise; Bale, Stuart D.; Barczynski, Krzysztof; Mandrini, Cristina; Polito, Vanessa; Warren, Harry P. Bibcode: 2021ApJ...917...25B Altcode: 2021arXiv210603318B Active regions are thought to be one contributor to the slow solar wind. Upflows in EUV coronal spectral lines are routinely observed at their boundaries, and provide the most direct way for upflowing material to escape into the heliosphere. The mechanisms that form and drive these upflows, however, remain to be fully characterized. It is unclear how quickly they form, or how long they exist during their lifetimes. They could be initiated low in the atmosphere during magnetic flux emergence, or as a response to processes occurring high in the corona when the active region is fully developed. On 2019 March 31 a simple bipolar active region (AR 12737) emerged and upflows developed on each side. We used observations from Hinode, SDO, IRIS, and Parker Solar Probe (PSP) to investigate the formation and development of the upflows from the eastern side. We used the spectroscopic data to detect the upflow, and then used the imaging data to try to trace its signature back to earlier in the active region emergence phase. We find that the upflow forms quickly, low down in the atmosphere, and that its initiation appears associated with a small field-opening eruption and the onset of a radio noise storm detected by PSP. We also confirmed that the upflows existed for the vast majority of the time the active region was observed. These results suggest that the contribution to the solar wind occurs even when the region is small, and continues for most of its lifetime. Title: A journey of exploration to the polar regions of a star: probing the solar poles and the heliosphere from high helio-latitude Authors: Harra, Louise; Andretta, Vincenzo; Appourchaux, Thierry; Baudin, Frédéric; Bellot-Rubio, Luis; Birch, Aaron C.; Boumier, Patrick; Cameron, Robert H.; Carlsson, Matts; Corbard, Thierry; Davies, Jackie; Fazakerley, Andrew; Fineschi, Silvano; Finsterle, Wolfgang; Gizon, Laurent; Harrison, Richard; Hassler, Donald M.; Leibacher, John; Liewer, Paulett; Macdonald, Malcolm; Maksimovic, Milan; Murphy, Neil; Naletto, Giampiero; Nigro, Giuseppina; Owen, Christopher; Martínez-Pillet, Valentín; Rochus, Pierre; Romoli, Marco; Sekii, Takashi; Spadaro, Daniele; Veronig, Astrid; Schmutz, W. Bibcode: 2021ExA...tmp...93H Altcode: 2021arXiv210410876H A mission to view the solar poles from high helio-latitudes (above 60°) will build on the experience of Solar Orbiter as well as a long heritage of successful solar missions and instrumentation (e.g. SOHO Domingo et al. (Solar Phys. 162(1-2), 1-37 1995), STEREO Howard et al. (Space Sci. Rev. 136(1-4), 67-115 2008), Hinode Kosugi et al. (Solar Phys. 243(1), 3-17 2007), Pesnell et al. Solar Phys. 275(1-2), 3-15 2012), but will focus for the first time on the solar poles, enabling scientific investigations that cannot be done by any other mission. One of the major mysteries of the Sun is the solar cycle. The activity cycle of the Sun drives the structure and behaviour of the heliosphere and of course, the driver of space weather. In addition, solar activity and variability provides fluctuating input into the Earth climate models, and these same physical processes are applicable to stellar systems hosting exoplanets. One of the main obstructions to understanding the solar cycle, and hence all solar activity, is our current lack of understanding of the polar regions. In this White Paper, submitted to the European Space Agency in response to the Voyage 2050 call, we describe a mission concept that aims to address this fundamental issue. In parallel, we recognise that viewing the Sun from above the polar regions enables further scientific advantages, beyond those related to the solar cycle, such as unique and powerful studies of coronal mass ejection processes, from a global perspective, and studies of coronal structure and activity in polar regions. Not only will these provide important scientific advances for fundamental stellar physics research, they will feed into our understanding of impacts on the Earth and other planets' space environment. Title: Comparison of active region upflow and core properties using simultaneous spectroscopic observations from IRIS and Hinode Authors: Barczynski, Krzysztof; Harra, Louise; Kleint, Lucia; Panos, Brandon; Brooks, David H. Bibcode: 2021A&A...651A.112B Altcode: 2021arXiv210410234B Context. The origin of the slow solar wind is still an open issue. It has been suggested that upflows at the edge of active regions are a possible source of the plasma outflow and therefore contribute to the slow solar wind.
Aims: We investigate the origin and morphology of the upflow regions and compare the upflow region and the active region core properties.
Methods: We studied how the plasma properties of flux, Doppler velocity, and non-thermal velocity change throughout the solar atmosphere, from the chromosphere via the transition region to the corona in the upflow region and the core of an active region. We studied limb-to-limb observations of the active region (NOAA 12687) obtained from 14 to 25 November 2017. We analysed spectroscopic data simultaneously obtained from IRIS and Hinode/EIS in the six emission lines Mg II 2796.4Å, C II 1335.71Å, Si IV 1393.76Å, Fe XII 195.12Å, Fe XIII 202.04Å, and Fe XIV 270.52Å and 274.20Å. We studied the mutual relationships between the plasma properties for each emission line, and we compared the plasma properties between the neighbouring formation temperature lines. To find the most characteristic spectra, we classified the spectra in each wavelength using the machine learning technique k-means.
Results: We find that in the upflow region the Doppler velocities of the coronal lines are strongly correlated, but the transition region and coronal lines show no correlation. However, their fluxes are strongly correlated. The upflow region has a lower density and lower temperature than the active region core. In the upflow region, the Doppler velocity and non-thermal velocity show a strong correlation in the coronal lines, but the correlation is not seen in the active region core. At the boundary between the upflow region and the active region core, the upflow region shows an increase in the coronal non-thermal velocity, the emission obtained from the DEM, and the domination of the redshifted regions in the chromosphere.
Conclusions: The obtained results suggest that at least three parallel mechanisms generate the plasma upflow: (1) The reconnection between closed loops and open magnetic field lines in the lower corona or upper chromosphere; (2) the reconnection between the chromospheric small-scale loops and open magnetic field; and (3) the expansion of the magnetic field lines that allows the chromospheric plasma to escape to the solar corona. Title: Vector Velocities Measurements with the Solar Orbiter SPICE Spectrometer Authors: Podladchikova, O.; Harra, L.; Barczynski, K.; Mandrini, C.; Auchère, F.; Berghmans, D.; Buchlin, E.; Dolla, L.; Mierla, M.; Parenti, S.; Rodriguez, L. Bibcode: 2021AAS...23831312P Altcode: The Solar Orbiter mission, with an orbit outside the Sun-Earth line and leaving the ecliptic plane, opens up opportunities for the combined analysis of measurements obtained by solar imagers and spectrometers. For the first time, different spectrometers will be located at wide angles to each other, allowing three-dimensional (3D) spectroscopy of the solar atmosphere. Here we develop a methodology to prepare for this kind of analysis, by using data from the Hinode mission and the Solar Dynamics Observatory, respectively. We employ solar rotation to simulate measurements of spectrometers with different views of the solar corona. The resulting data allow us to apply stereoscopic tie-pointing and triangulation techniques designed for the STEREO spacecraft pair, and to perform 3D analysis of the Doppler shifts of a quasi-stationary active region. Our approach allows the accurate reconstruction of 3D velocity vectors in plasma flows along "open" and "closed" magnetic loops. This technique will be applied to the actual situation of two spacecraft at different separations with spectrometers on board (the Solar Orbiter Spectral Imaging of the Coronal Environment versus the Interface Region Imaging Spectrograph (IRIS) and Hinode imaging spectrometer) and we summarise how these observations can be coordinated to assess vector velocity measurements. This 3D spectroscopy method will facilitate the understanding of the complex flows that take place throughout the solar atmosphere. Title: The active region source of a type III radio storm observed by Parker Solar Probe during encounter 2 Authors: Harra, L.; Brooks, D. H.; Bale, S. D.; Mandrini, C. H.; Barczynski, K.; Sharma, R.; Badman, S. T.; Vargas Domínguez, S.; Pulupa, M. Bibcode: 2021A&A...650A...7H Altcode: 2021arXiv210204964H Context. We investigated the source of a type III radio burst storm during encounter 2 of NASA's Parker Solar Probe (PSP) mission.
Aims: It was observed that in encounter 2 of NASA's PSP mission there was a large amount of radio activity and, in particular, a noise storm of frequent, small type III bursts from 31 March to 6 April 2019. Our aim is to investigate the source of these small and frequent bursts.
Methods: In order to do this, we analysed data from the Hinode EUV Imaging Spectrometer, PSP FIELDS, and the Solar Dynamics Observatory Atmospheric Imaging Assembly. We studied the behaviour of active region 12737, whose emergence and evolution coincides with the timing of the radio noise storm and determined the possible origins of the electron beams within the active region. To do this, we probed the dynamics, Doppler velocity, non-thermal velocity, FIP bias, and densities, and carried out magnetic modelling.
Results: We demonstrate that although the active region on the disc produces no significant flares, its evolution indicates it is a source of the electron beams causing the radio storm. They most likely originate from the area at the edge of the active region that shows strong blue-shifted plasma. We demonstrate that as the active region grows and expands, the area of the blue-shifted region at the edge increases, which is also consistent with the increasing area where large-scale or expanding magnetic field lines from our modelling are anchored. This expansion is most significant between 1 and 4 April 2019, coinciding with the onset of the type III storm and the decrease of the individual burst's peak frequency, indicating that the height at which the peak radiation is emitted increases as the active region evolves. Title: Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST) Authors: Rast, Mark P.; Bello González, Nazaret; Bellot Rubio, Luis; Cao, Wenda; Cauzzi, Gianna; Deluca, Edward; de Pontieu, Bart; Fletcher, Lyndsay; Gibson, Sarah E.; Judge, Philip G.; Katsukawa, Yukio; Kazachenko, Maria D.; Khomenko, Elena; Landi, Enrico; Martínez Pillet, Valentín; Petrie, Gordon J. D.; Qiu, Jiong; Rachmeler, Laurel A.; Rempel, Matthias; Schmidt, Wolfgang; Scullion, Eamon; Sun, Xudong; Welsch, Brian T.; Andretta, Vincenzo; Antolin, Patrick; Ayres, Thomas R.; Balasubramaniam, K. S.; Ballai, Istvan; Berger, Thomas E.; Bradshaw, Stephen J.; Campbell, Ryan J.; Carlsson, Mats; Casini, Roberto; Centeno, Rebecca; Cranmer, Steven R.; Criscuoli, Serena; Deforest, Craig; Deng, Yuanyong; Erdélyi, Robertus; Fedun, Viktor; Fischer, Catherine E.; González Manrique, Sergio J.; Hahn, Michael; Harra, Louise; Henriques, Vasco M. J.; Hurlburt, Neal E.; Jaeggli, Sarah; Jafarzadeh, Shahin; Jain, Rekha; Jefferies, Stuart M.; Keys, Peter H.; Kowalski, Adam F.; Kuckein, Christoph; Kuhn, Jeffrey R.; Kuridze, David; Liu, Jiajia; Liu, Wei; Longcope, Dana; Mathioudakis, Mihalis; McAteer, R. T. James; McIntosh, Scott W.; McKenzie, David E.; Miralles, Mari Paz; Morton, Richard J.; Muglach, Karin; Nelson, Chris J.; Panesar, Navdeep K.; Parenti, Susanna; Parnell, Clare E.; Poduval, Bala; Reardon, Kevin P.; Reep, Jeffrey W.; Schad, Thomas A.; Schmit, Donald; Sharma, Rahul; Socas-Navarro, Hector; Srivastava, Abhishek K.; Sterling, Alphonse C.; Suematsu, Yoshinori; Tarr, Lucas A.; Tiwari, Sanjiv; Tritschler, Alexandra; Verth, Gary; Vourlidas, Angelos; Wang, Haimin; Wang, Yi-Ming; NSO and DKIST Project; DKIST Instrument Scientists; DKIST Science Working Group; DKIST Critical Science Plan Community Bibcode: 2021SoPh..296...70R Altcode: 2020arXiv200808203R The National Science Foundation's Daniel K. Inouye Solar Telescope (DKIST) will revolutionize our ability to measure, understand, and model the basic physical processes that control the structure and dynamics of the Sun and its atmosphere. The first-light DKIST images, released publicly on 29 January 2020, only hint at the extraordinary capabilities that will accompany full commissioning of the five facility instruments. With this Critical Science Plan (CSP) we attempt to anticipate some of what those capabilities will enable, providing a snapshot of some of the scientific pursuits that the DKIST hopes to engage as start-of-operations nears. The work builds on the combined contributions of the DKIST Science Working Group (SWG) and CSP Community members, who generously shared their experiences, plans, knowledge, and dreams. Discussion is primarily focused on those issues to which DKIST will uniquely contribute. Title: Matching Temporal Signatures of Solar Features to Their Corresponding Solar-Wind Outflows Authors: de Pablos, D.; Long, D. M.; Owen, C. J.; Valori, G.; Nicolaou, G.; Harra, L. K. Bibcode: 2021SoPh..296...68D Altcode: 2021arXiv210309077D The role of small-scale coronal eruptive phenomena in the generation and heating of the solar wind remains an open question. Here, we investigate the role played by coronal jets in forming the solar wind by testing whether temporal variations associated with jetting in EUV intensity can be identified in the outflowing solar-wind plasma. This type of comparison is challenging due to inherent differences between remote-sensing observations of the source and in-situ observations of the outflowing plasma, as well as travel time and evolution of the solar wind throughout the heliosphere. To overcome these, we propose a novel algorithm combining signal filtering, two-step solar-wind ballistic back-mapping, window shifting, and Empirical Mode Decomposition. We first validate the method using synthetic data, before applying it to measurements from the Solar Dynamics Observatory and Wind spacecraft. The algorithm enables the direct comparison of remote-sensing observations of eruptive phenomena in the corona to in-situ measurements of solar-wind parameters, among other potential uses. After application to these datasets, we find several time windows where signatures of dynamics found in the corona are embedded in the solar-wind stream, at a time significantly earlier than expected from simple ballistic back-mapping, with the best-performing in-situ parameter being the solar-wind mass flux. Title: Upflows in the Upper Solar Atmosphere Authors: Tian, Hui; Harra, Louise; Baker, Deborah; Brooks, David H.; Xia, Lidong Bibcode: 2021SoPh..296...47T Altcode: 2021arXiv210202429T Spectroscopic observations at extreme- and far-ultraviolet wavelengths have revealed systematic upflows in the solar transition region and corona. These upflows are best seen in the network structures of the quiet Sun and coronal holes, boundaries of active regions, and dimming regions associated with coronal mass ejections. They have been intensively studied in the past two decades because they are likely to be closely related to the formation of the solar wind and heating of the upper solar atmosphere. We present an overview of the characteristics of these upflows, introduce their possible formation mechanisms, and discuss their potential roles in the mass and energy transport in the solar atmosphere. Although past investigations have greatly improved our understanding of these upflows, they have left us with several outstanding questions and unresolved issues that should be addressed in the future. New observations from the Solar Orbiter mission, the Daniel K. Inouye Solar Telescope, and the Parker Solar Probe will likely provide critical information to advance our understanding of the generation, propagation, and energization of these upflows. Title: Stereoscopic Measurements of Coronal Doppler Velocities aboard Solar Orbiter Authors: Podladchikova, Olena; Harra, Louise K.; Mandrini, Cristina H.; Rodriguez, Luciano; Parenti, Susanna; Dolla, Laurent; Buchlin, Eric; Auchere, Frederic; Mierla, Marilena; Barczynski, Krzysztof Bibcode: 2021cosp...43E.957P Altcode: The Solar Orbiter mission, whose orbit is outside the Sun-Earth line, opens up novel opportunities for the combined analysis of measurements by solar imagers and spectrometers. For the first time different spectrometers will be located at wide angles with each other allowing 3D spectroscopy in the solar atmosphere. In order to develop a methodology for these opportunities we make use of the Hinode EUV Imaging Spectrometer (EIS) and Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) and by employing solar rotation we simulate the measurements of spectrometers that have different views of solar corona. The resulting data allows us to apply stereoscopic tie-pointing and triangulation techniques designed for SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) imaging suite on the STEREO (Solar Terrestrial Relations Observatory) spacecraft pair and perform three-dimensional analysis of Doppler shifts of quasi-stationary active region.We present a technique that allows the accurate reconstruction of the 3D velocity vector in plasma flows along open and closed magnetic loops. This technique will be applied to the real situation of two spacecraft at different separations with spectrometers onboard. This will include the Solar Orbiter Spectral Imaging of the Coronal Environment (SPICE), the Solar Orbiter Extreme Ultraviolet Imager (EUI), the Interface Region Imaging Spectrograph (IRIS) and Hinode EIS spectrometers and we summarise how these can be coordinated. This 3D spectroscopy is a new research domain that will aid the understanding of the complex flows that take place throughout the solar atmosphere. Title: Coronal 'camp-fires' in the quiet Sun as observed by Solar Orbiter EUV Imagers Authors: Harra, Louise K. Bibcode: 2021cosp...43E.950H Altcode: The quiet Sun is known to be extremely dynamic, with an array of small-scale energy releases occurring in features such as network and internetwork, bright points, and are observed throughout the solar atmosphere - from the photosphere to the corona. The Interface Region Imaging Spectrograph (IRIS) data shows UV bursts (e.g. Young et al., 2018), that have at least an order of magnitude enhancement in intensity, show strong flows, and are on spatial scales of 500-1000km. These are often associated with opposite polarity magnetic fragments that cancel, and are observed in the transition region. Similar phenomena are seen in the optical bands called Ellerman bombs or more recently quiet Sun Ellerman-like brightenings (QSEB, van der Voort et al., 2016). Coronal brightenings are also readily observed and there is significant interest in these, to understand whether they contribute to the heating of the corona. Statistical studies of these coronal brightenings have shown a power-law behaviour, and this has found to be around 1.8 (e.g. Aschwanden et al., 2000). There is a strong interesting in understanding the smaller-scale events to determine if they can indeed heat the corona. To do this the spatial resolution must be high. The Hi-C rocket flights have observed with spatial resolutions of 100 km, and small-scale brightenings have been seen at the se size scales (e.g. Winbarger et al., 2013). The EUV Imagers (EUI) on Solar Orbiter has taken the first commissioning data in 2020, and in this presentation, we describe the smallest features yet seen in the EUV that have been coined 'camp-fires'. We describe their characteristics, and discuss future observations once we're in the true science phase of the mission at the end of 2021. Title: The Extreme ultraviolet imager onboard Solar Orbiter Authors: Berghmans, David; Harra, Louise K.; Zhukov, Andrei; Auchere, Frederic; Long, David; Schuehle, Udo; Rochus, Pierre Bibcode: 2021cosp...43E.949B Altcode: The Extreme Ultraviolet Imager (EUI) is part of the remote sensing instrument package of the ESA/NASA Solar Orbiter mission that will explore the inner heliosphere and observe the Sun from vantage points close to the Sun and out of the ecliptic. With EUI we aim to improve our understanding of the structure and dynamics of the solar atmosphere, globally as well as at high resolution, and from high solar latitude perspectives. The EUI consists of three telescopes, the Full Sun Imager (FSI) and two High Resolution Imagers (HRIs), which are optimised to image in Lyman-$\alpha$ and EUV (174 \AA, 304 \AA) to provide a coverage from chromosphere up to corona. The EUI instrument design will be reviewed, and its scientific objectives and plans will be discussed. Early results of the EUI commissioning will be presented. Title: The creation of blue-shifted regions in an active region that lead to the onset of a radio nise storm. Authors: Harra, Louise K. Bibcode: 2021cosp...43E.958H Altcode: On 31st March 2019, a new simple bipolar active region emerged in the NE of the Sun. This region formed from a small bright point, and developed through expansion. For the first time, we observe the development and expansion of the loops with time, and with magnetic modelling see how the region at the edge of the active region form an increasing number of open magnetic field lines. We see the development of the region where blue-shifts form. These blue-shifted regions are always seen at the edges of active regions as observed by the Hinode EUV Imagining Spectrometer (EIS), and we discuss how they are formed. Alongside these observations, Parker Solar Probe observed a radio noise storm. We track how the blue-shifted and the radio data increase as the active region develops in its first few days of life. The blue-shifted regions on the active region seems to be the source of the radio noise storm, confirming their importance as a contributor to the solar wind. Title: Relative coronal abundance diagnostics with Solar Orbiter/SPICE Authors: Zambrana Prado, N.; Buchlin, E.; Peter, H.; Young, P. R.; Auchere, F.; Carlsson, M.; Fludra, A.; Hassler, D.; Aznar Cuadrado, R.; Caminade, S.; Caldwell, M.; DeForest, C.; Fredvik, T.; Harra, L.; Janvier, M.; Kucera, T. A.; Giunta, A. S.; Grundy, T.; Müller, D.; Parenti, S.; Schmutz, W. K.; Schühle, U.; Sidher, S.; Teriaca, L.; Thompson, W. T.; Williams, D. Bibcode: 2020AGUFMSH038..09Z Altcode: Linking solar activity on the surface and in the corona to the inner heliosphere is one of Solar Orbiter's main goals. Its UV spectrometer SPICE (SPectral Imaging of the Coronal Environment) will provide relative abundance measurements which will be key in this quest as different structures on the Sun have different abundances as a consequence of the FIP (First Ionization Potential) effect. Solar Orbiter's unique combination of remote sensing and in-situ instruments coupled with observation from other missions such as Parker Solar Probe will allow us to compare in-situ and remote sensing composition data. With the addition of modeling, these new results will allow us to trace back the source of heliospheric plasma. As high telemetry will not always be available with SPICE, we have developed a method for measuring relative abundances that is both telemetry efficient and reliable. Unlike methods based on Differential Emission Measure (DEM) inversion, the Linear Combination Ratio (LCR) method does not require a large number of spectral lines. This new method is based on linear combinations of UV spectral lines. The coefficients of the combinations are optimized such that the ratio of two linear combinations of radiances would yield the relative abundance of two elements. We present some abundance diagnostics tested on different combinations of spectral lines observable by SPICE. Title: Dynamics and thermal structure in the quiet Sun seen by SPICE Authors: Peter, H.; Aznar Cuadrado, R.; Schühle, U.; Teriaca, L.; Auchere, F.; Carlsson, M.; Fludra, A.; Hassler, D.; Buchlin, E.; Caminade, S.; Caldwell, M.; DeForest, C.; Fredvik, T.; Harra, L. K.; Janvier, M.; Kucera, T. A.; Giunta, A. S.; Grundy, T.; Müller, D.; Parenti, S.; Schmutz, W. K.; Sidher, S.; Thompson, W. T.; Williams, D.; Young, P. R. Bibcode: 2020AGUFMSH038..03P Altcode: We will present some of the early data of the Spectral Imaging of the Coronal Environment (SPICE) instrument on Solar Orbiter. One of the unique features of SPICE is its capability to record a wide range of wavelengths in the extreme UV with the possibility to record spectral lines giving access to a continuous plasma temperature range from 10.000 K to well above 1 MK. The data taken so far were for commissioning purposes and they can be used for a preliminary evaluation of the science performance of the instrument. Here we will concentrate on sample spectra covering the whole wavelength region and on the early raster maps acquired in bright lines in the quiet Sun close to disk center. Looking at different quiet Sun features we investigate the thermal structure of the atmosphere and flow structures. For this we apply fits to the spectral profiles and check the performance in terms of Doppler shifts and line widths to retrieve the structure of the network in terms of dynamics. While the amount of data available so far is limited, we will have a first look on how quiet Sun plasma responds to heating events. For this, we will compare spectral lines forming at different temperatures recorded at strictly the same time. Title: A Journey of Exploration to the Polar Regions of a Star: Probing the Solar Poles and the Heliosphere from High Helio-Latitude Authors: Finsterle, W.; Harra, L.; Andretta, V.; Appourchaux, T.; Baudin, F.; Bellot Rubio, L.; Birch, A.; Boumier, P.; Cameron, R. H.; Carlsson, M.; Corbard, T.; Davies, J. A.; Fazakerley, A. N.; Fineschi, S.; Gizon, L. C.; Harrison, R. A.; Hassler, D.; Leibacher, J. W.; Liewer, P. C.; Macdonald, M.; Maksimovic, M.; Murphy, N.; Naletto, G.; Nigro, G.; Owen, C. J.; Martinez-Pillet, V.; Rochus, P. L.; Romoli, M.; Sekii, T.; Spadaro, D.; Veronig, A. Bibcode: 2020AGUFMSH0110005F Altcode: A mission to view the solar poles from high helio-latitudes (above 60°) will build on the experience of Solar Orbiter as well as a long heritage of successful solar missions and instrumentation (e.g. SOHO, STEREO, Hinode, SDO), but will focus for the first time on the solar poles, enabling scientific investigations that cannot be done by any other mission. One of the major mysteries of the Sun is the solar cycle. The activity cycle of the Sun drives the structure and behaviour of the heliosphere and is, of course, the driver of space weather. In addition, solar activity and variability provides fluctuating input into the Earth climate models, and these same physical processes are applicable to stellar systems hosting exoplanets. One of the main obstructions to understanding the solar cycle, and hence all solar activity, is our current lack of understanding of the polar regions. We describe a mission concept that aims to address this fundamental issue. In parallel, we recognise that viewing the Sun from above the polar regions enables further scientific advantages, beyond those related to the solar cycle, such as unique and powerful studies of coronal mass ejection processes, from a global perspective, and studies of coronal structure and activity in polar regions. Not only will these provide important scientific advances for fundamental stellar physics research, they will feed into our understanding of impacts on the Earth and other planets' space environment. Title: A Comparison of the Active Region Upflow and Core Morphologies Using Simultaneous Spectroscopic Observations from IRIS and Hinode. Authors: Barczynski, K.; Harra, L. K.; Kleint, L.; Panos, B. Bibcode: 2020AGUFMSH004..05B Altcode: The origin of the slow solar wind is still an open issue. It has been suggested that upflows at the edge of the active region are the source of the plasma outflow, and therefore contribute to the slow solar wind . However, the origin and morphology of the upflow region remain open questions. We investigated how the plasma properties (flux, Doppler velocity, and non-thermal velocity) change throughout the solar atmosphere, from the chromosphere via the transition region to the corona. We compared the upflow region and the core of an active region. We studied limb-to-limb observation of the active region (NOAA 12687) obtained between 14th and 25th November 2017. We analyzed spectroscopic data simultaneously obtained from Hinode/EIS and IRIS in six wavelengths (MgII, CII, SiIV, FeXII, FeXIII, and FeXIV). After the high-precision alignment (accuracy of the Hinode pixel size) of the raster maps, we studied the mutual relation between the plasma properties for each line, as well as compared the plasma properties in the close formation temperature lines. To find the most characteristic spectra, we classified the spectra in each wavelength using the machine learning technique k-means . We found that the fluxes of the lines formed in the close temperatures are highly correlated in the chromosphere via transition region to the corona. In the corona, the Doppler velocities are well correlated too. Despite high-correlation between the transition region and coronal fluxes, the Doppler velocities are independent in our active region. In coronal lines, the average non-thermal velocity is higher in the upflow region than the active region core. In the transition region, the velocities are similar; thus the non-thermal motions are essential in the coronal upflow. We found several mutual relations between the plasma parameters in different spectral lines. These relations and the spectra classification results suggest that the plasma upflow begins in the solar corona, but the nature of the upflow region can be determined from the underlying layers. Title: Analysis of time-domain correlations between EUV and in-situ observations of coronal jets Authors: de Pablos, D.; Owen, C. J.; Long, D.; Harra, L. K.; Valori, G.; Nicolaou, G. Bibcode: 2020AGUFMSH0290018D Altcode: The role of small-scale coronal eruptive phenomena in the origin and heating of the solar wind remains an open question. In this work we attempt to determine the role played by coronal jets in forming the solar wind. This is a challenging problem due to inherent differences between remote-sensing observations of the source and in-situ observations of the outflowing plasma, as well as its travel time and evolution throughout the heliosphere. To overcome these challenges, we propose the use of Empirical Mode Decomposition to enable direct comparison of temporal signatures within remote sensing observations of eruptive phenomena in the corona and in-situ measurements of the solar wind. The technique is first validated using artificial data before being applied to measurements from the Solar Dynamics Observatory and Wind spacecraft. We discuss the potential reasons for discrepancies between results from the artificial data and observations at 1 AU, and their implications on the solar wind nature. Title: Observation of Smallest Ever Detected Brightening Events with the Solar Orbiter EUI HRI-EUV Imager Authors: Parenti, S.; Berghmans, D.; Buchlin, E.; Teriaca, L.; Auchere, F.; Harra, L.; Long, D.; Rochus, P. L.; Schühle, U.; Aznar Cuadrado, R.; Gissot, S.; Kraaikamp, E.; Smith, P.; Stegen, K.; Verbeeck, C. Bibcode: 2020AGUFMSH038..01P Altcode: The Extreme Ultraviolet Imager (EUI) suite on board Solar Orbiter acquired its first images in May 2020. The passband of the 17.4 nm High Resolution Imager (HRI-EUV) is dominated by emission lines of Fe IX and Fe X, that is the 1 million degree solar corona. The solar atmosphere at this temperature is dynamic at all scales, down to the highest spatial resolution available from instruments priori to Solar Orbiter. During the Commissioning phase, HRI-EUV acquired several high temporal resolution (a few seconds) sequences at quiet Sun regions at disk center. The instrument revealed a multitude of brightenings at the smallest-ever detectable spatial scales which, at that time, was about 400 km (two pixels). These events appear to be present everywhere all the time. We present the first results of the analysis of these sequences with the aim of understanding the role of these small scale events in the heating of the solar corona. Title: Stereoscopic Measurements of Coronal Doppler Velocities Authors: Podladchikova, O.; Harra, L. K.; Barczynski, K.; Mandrini, C. H.; Auchere, F.; Buchlin, E.; Dolla, L.; Mierla, M.; Rodriguez, L. Bibcode: 2020AGUFMSH038..07P Altcode: The Solar Orbiter mission, whose orbit is outside the Sun-Earth line, opens up novel opportunities for the combined analysis of measurements by solar imagers and spectrometers. For the first time different spectrometers will be located at wide angles with each other allowing 3D spectroscopy in the solar atmosphere. In order to develop a methodology for these opportunities we make use of the Hinode EUV Imaging Spectrometer (EIS) and Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) and by employing solar rotation we simulate the measurements of two spectrometers that have different views of solar corona. The resulting data allows us to apply stereoscopic tie-pointing and triangulation techniques designed for SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) imaging suite on the STEREO (Solar Terrestrial Relations Observatory) spacecraft pair and perform three-dimensional analysis of Doppler shifts of quasi-stationary active region. We present a technique that allows the accurate reconstruction of the 3D velocity vector in plasma flows along open and closed magnetic loops. This technique will be applied to the real situation of two spacecraft at different separations with spectrometers onboard. This will include the Solar Orbiter Spectral Imaging of the Coronal Environment (SPICE), the Solar Orbiter Extreme Ultraviolet Imager (EUI),the Interface Region Imaging Spectrograph (IRIS) and Hinode EIS spectrometers and we summarise how these can be coordinated. This 3D spectroscopy is a new research domain that will aid the understanding of the complex flows that take place throughout the solar atmosphere. Title: Constraining Global Coronal Models with Multiple Independent Observables Authors: Badman, S. T.; Brooks, D.; Petrie, G. J. D.; Poirier, N.; Warren, H.; Bale, S. D.; de Pablos, D.; Harra, L.; Rouillard, A. P.; Panasenco, O.; Velli, M. C. M. Bibcode: 2020AGUFMSH032..08B Altcode: Global coronal models seek to produce an accurate physical representation of the Sun's atmosphere which can be used to probe the dominant plasma physics processes, to connect remote and in situ observations and operationally to predict space weather events which can impact the Earth. Assessing their accuracy and usefulness is a complex task and there are multiple observational pathways to provide constraints on such models and tune their input parameters. In this work, we aim to combine several such independent constraints in a systematic fashion on coronal models. We study the intervals of Parker Solar Probe's early solar encounters to leverage the unique in situ observations taken close to the Sun, and the wealth of supporting observations and prior work analyzing these time intervals. We require our coronal models to predict the distribution of coronal holes on the solar surface, and the neutral line topology. We compare these predictions to (1) direct Extreme Ultraviolet (EUV) observations of coronal hole locations, (2) white light Carrington maps of the probable neutral line location at a few solar radii, (3) the magnetic sector structure measured in situ by Parker Solar Probe as well as 1AU assets. For each of these constraints we compute a simple metric to evaluate model agreement and compare and contrast these metrics to evaluate and rank the overall accuracy of the models over a range of input parameters. Initial results using the coronal hole metric to analyze Potential Field Source Surface (PFSS) models indicate the optimum source surface height (Rss) parameter varied from encounter to encounter. Rss = 1.5 - 2.0 R_sun is shown to work best for Encounters 1 and 3, but higher (2.0-2.5 R_sun) for encounter 2, in agreement with the magnetic sector structure metric and previous work (e.g. Panasenco et al. 2020). We discuss the extension of these results to all three metrics, assess differences in model accuracy among input photospheric boundary conditions and investigate models with more physics than PFSS. Title: First Results From SPICE EUV Spectrometer on Solar Orbiter Authors: Fludra, A.; Caldwell, M.; Giunta, A. S.; Grundy, T.; Guest, S.; Sidher, S.; Auchere, F.; Carlsson, M.; Hassler, D.; Peter, H.; Aznar Cuadrado, R.; Buchlin, E.; Caminade, S.; DeForest, C.; Fredvik, T.; Harra, L. K.; Janvier, M.; Kucera, T. A.; Leeks, S.; Mueller, D.; Parenti, S.; Schmutz, W. K.; Schühle, U.; Teriaca, L.; Thompson, W. T.; Tustain, S.; Williams, D.; Young, P. R. Bibcode: 2020AGUFMSH038..02F Altcode: SPICE (Spectral Imaging of Coronal Environment) is one of the remote sensing instruments onboard Solar Orbiter. It is an EUV imaging spectrometer observing the Sun in two wavelength bands: 69.6-79.4 nm and 96.6-105.1 nm. SPICE is capable of recording full spectra in these bands with exposures as short as 1s. SPICE is the only Solar Orbiter instrument that can measure EUV spectra from the disk and low corona of the Sun and record all spectral lines simultaneously. SPICE uses one of three narrow slits, 2"x11', 4''x11', 6''x11', or a wide slit 30''x14'. The primary mirror can be scanned in a direction perpendicular to the slit, allowing raster images of up to 16' in size.

We present an overview of the first SPICE data taken on several days during the instrument commissioning carried out by the RAL Space team between 2020 April 21 and 2020 June 14. We also include results from SPICE observations at the first Solar Orbiter perihelion at 0.52AU, taken between June 16-21st. We give examples of full spectra from the quiet Sun near disk centre and provide a list of key spectral lines emitted in a range of temperatures between 10,000 K and over 1 million K, from neutral hydrogen and ions of carbon, oxygen, nitrogen, neon, sulphur and magnesium. We show examples of first raster images in several strong lines, obtained with different slits and a range of exposure times between 5s and 180s. We describe the temperature coverage and density diagnostics, determination of plasma flows, and discuss possible applications to studies of the elemental abundances in the corona. We also show the first off-limb measurements with SPICE, as obtained when the spacecraft pointed at the limb. Title: The Solar-C (EUVST) mission: the latest status Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kawate, Tomoko; Suematsu, Yoshinori; Hara, Hirohisa; Tsuzuki, Toshihiro; Katsukawa, Yukio; Kubo, Masahito; Ishikawa, Ryoko; Watanabe, Tetsuya; Toriumi, Shin; Ichimoto, Kiyoshi; Nagata, Shin'ichi; Hasegawa, Takahiro; Yokoyama, Takaaki; Watanabe, Kyoko; Tsuno, Katsuhiko; Korendyke, Clarence M.; Warren, Harry; De Pontieu, Bart; Boerner, Paul; Solanki, Sami K.; Teriaca, Luca; Schuehle, Udo; Matthews, Sarah; Long, David; Thomas, William; Hancock, Barry; Reid, Hamish; Fludra, Andrzej; Auchère, Frederic; Andretta, Vincenzo; Naletto, Giampiero; Poletto, Luca; Harra, Louise Bibcode: 2020SPIE11444E..0NS Altcode: Solar-C (EUVST) is the next Japanese solar physics mission to be developed with significant contributions from US and European countries. The mission carries an EUV imaging spectrometer with slit-jaw imaging system called EUVST (EUV High-Throughput Spectroscopic Telescope) as the mission payload, to take a fundamental step towards answering how the plasma universe is created and evolves and how the Sun influences the Earth and other planets in our solar system. In April 2020, ISAS (Institute of Space and Astronautical Science) of JAXA (Japan Aerospace Exploration Agency) has made the final down-selection for this mission as the 4th in the series of competitively chosen M-class mission to be launched with an Epsilon launch vehicle in mid 2020s. NASA (National Aeronautics and Space Administration) has selected this mission concept for Phase A concept study in September 2019 and is in the process leading to final selection. For European countries, the team has (or is in the process of confirming) confirmed endorsement for hardware contributions to the EUVST from the national agencies. A recent update to the mission instrumentation is to add a UV spectral irradiance monitor capability for EUVST calibration and scientific purpose. This presentation provides the latest status of the mission with an overall description of the mission concept emphasizing on key roles of the mission in heliophysics research from mid 2020s. Title: Dynamics and Flows in Active Region NOAA12737 that can contribute to Type III Bursts observed by Parker Solar Probe during Encounter 2. Authors: Harra, L.; Brooks, D.; Barczynski, K.; Mandrini, C. H.; Vargas-Dominguez, S.; Bale, S.; Badman, S. T.; Raouafi, N. E.; Rouillard, A. P. Bibcode: 2020AGUFMSH0240001H Altcode: We have analysed solar activity on the Sun during encounter 2 of the Parker Solar Probe mission. We studied the period from 30th March to 4th April when a small active region (NOAA 12737) emerged. This active region showed no significant flaring. During this time period there were however, an increasing number of type III bursts measured by the FIELDS instrument. We analyse solar data from SDO-AIA, SDO-HMI and Hinode EIS to determine what the potential sources of the type III bursts could be, which occur on timescales of tens of seconds. The active region core shows small brightenings in EUV and X-ray wavebands, but these are not continuous, and seem unlikely to be connected. There are magnetic field changes due to the active region emergence, which occur on timescales of hours rather than seconds. There are small scale magnetic flux emergences but these are not frequent enough to be linked to the continuous type III bursts. As the active region emerges, we track the upflows at the edge of the active region as they are created and evolve. We show evidence of variations in the upflows that seem to be the most likely candidates for the sources of the type III bursts. Title: Current Status of the Solar-C_EUVST Mission Authors: Imada, S.; Shimizu, T.; Kawate, T.; Toriumi, S.; Katsukawa, Y.; Kubo, M.; Hara, H.; Suematsu, Y.; Ichimoto, K.; Watanabe, T.; Watanabe, K.; Yokoyama, T.; Warren, H.; Long, D.; Harra, L. K.; Teriaca, L. Bibcode: 2020AGUFMSH056..05I Altcode: Solar-C_EUVST (EUV High-Throughput Spectroscopic Telescope) is designed to comprehensively understand the energy and mass transfer from the solar surface to the solar corona and interplanetary space, and to investigate the elementary processes that take place universally in cosmic plasmas. As a fundamental step towards answering how the plasma universe is created and evolves, and how the Sun influences the Earth and other planets in our solar system, the proposed mission is designed to comprehensively understand how mass and energy are transferred throughout the solar atmosphere. Understanding the solar atmosphere, which connects to the heliosphere via radiation, the solar wind and coronal mass ejections, and energetic particles is pivotal for establishing the conditions for life and habitability in the solar system.

The two primary science objectives for Solar-C_EUVST are : I) Understand how fundamental processes lead to the formation of the solar atmosphere and the solar wind, II) Understand how the solar atmosphere becomes unstable, releasing the energy that drives solar flares and eruptions. Solar-C_EUVST will, A) seamlessly observe all the temperature regimes of the solar atmosphere from the chromosphere to the corona at the same time, B) resolve elemental structures of the solar atmosphere with high spatial resolution and cadence to track their evolution, and C) obtain spectroscopic information on the dynamics of elementary processes taking place in the solar atmosphere.

In this talk, we will first discuss the science target of the Solar-C_EUVST, and then discuss the current status of the Solar-C_EUVST mission. Title: Calibrating optical distortions in the Solar Orbiter SPICE spectrograph Authors: Thompson, W. T.; Schühle, U.; Young, P. R.; Auchere, F.; Carlsson, M.; Fludra, A.; Hassler, D.; Peter, H.; Aznar Cuadrado, R.; Buchlin, E.; Caldwell, M.; DeForest, C.; Fredvik, T.; Harra, L. K.; Janvier, M.; Kucera, T. A.; Giunta, A. S.; Grundy, T.; Müller, D.; Parenti, S.; Caminade, S.; Schmutz, W. K.; Teriaca, L.; Williams, D.; Sidher, S. Bibcode: 2020AGUFMSH0360029T Altcode: The Spectral Imaging of the Coronal Environment (SPICE) instrument on Solar Orbiter is a high-resolution imaging spectrometer operating at extreme ultraviolet (EUV) wavelengths from 70.4-79.0 nm and 97.3-104.9 nm. A single-mirror off-axis paraboloid focuses the solar image onto the entrance slit of the spectrometer section. A Toroidal Variable Line Space (TVLS) grating images the entrance slit onto a pair of MCP-intensified APS detectors. Ray-tracing analysis prior to launch showed that the instrument was subject to a number of small image distortions which need to be corrected in the final data product. We compare the ray tracing results with measurements made in flight. Co-alignment with other telescopes on Solar Orbiter will also be examined. Title: First results from the EUI and SPICE observations of Alpha Leo near Solar Orbiter first perihelion Authors: Buchlin, E.; Teriaca, L.; Giunta, A. S.; Grundy, T.; Andretta, V.; Auchere, F.; Peter, H.; Berghmans, D.; Carlsson, M.; Fludra, A.; Harra, L.; Hassler, D.; Long, D.; Rochus, P. L.; Schühle, U.; Aznar Cuadrado, R.; Caldwell, M.; Caminade, S.; DeForest, C.; Fredvik, T.; Gissot, S.; Heerlein, K.; Janvier, M.; Kraaikamp, E.; Kucera, T. A.; Müller, D.; Parenti, S.; Schmutz, W. K.; Sidher, S.; Smith, P.; Stegen, K.; Thompson, W. T.; Verbeeck, C.; Williams, D.; Young, P. R. Bibcode: 2020AGUFMSH0360024B Altcode: On June 16th 2020 Solar Orbiter made a dedicated observing campaign where the spacecraft pointed to the solar limb to allow some of the high resolution instruments to observe the ingress (at the east limb) and later the egress (west limb) of the occultation of the star Alpha Leonis by the solar disk. The star was chosen because its luminosity and early spectral type ensure high and stable flux at wavelengths between 100 and 122 nanometers, a range observed by the High Resolution EUI Lyman alpha telescope (HRI-LYA) and by the long wavelength channel of the SPICE spectrograph. Star observations, when feasible, allow to gather a great deal of information on the instrument performances, such as the radiometric performance and the instrument optical point spread function (PSF).

We report here the first results from the above campaign for the two instruments. Title: Probing Upflowing Plasma in Solar Coronal Holes to Categorise the most frequent Events Authors: Schwanitz, C.; Harra, L. Bibcode: 2020AGUFMSH0110002S Altcode: Coronal holes have many dynamic events in them, such as jets, plumes, and small filament eruptions. In addition, a class of jets has been observed [Young P., 2015] that are only visible in line-of-sight Doppler velocity measurements and tend to appear in the vicinity of coronal holes. In this work solar polar blue-shifted regions are explored and their sources classified. Doppler velocity maps are derived from the Fe XII 195.2Å emission line in Hinode/EIS measurements and analysed in combination with imaging data from SDO/AIA and SDO/XRT to characterise the regions of upflowing plasma. Of the analysed blue-shift events, some could be explained by weak standard jets, while other events are connected to small flaring bright points. Some blue-shift events do not leave any significant trace in the imaging instruments. Their contribution to the solar wind is unknown yet, however recent findings from Parker Solar Probe data show that there are frequent small-scale dynamics in the wind, even during quiet times [Bale S.D., Badman S.T., Bonnell J.W. et al., 2019]. These findings emphasise the importance of understanding all upflowing plasma events in coronal holes. Finally future Solar Orbiter observations of polar coronal holes, particularly during the out of ecliptic phase, are discussed. Title: Solar Orbiter: connecting remote sensing and in situ measurements Authors: Horbury, T. S.; Auchere, F.; Antonucci, E.; Berghmans, D.; Bruno, R.; Carlsson, M.; del Toro Iniesta, J. C.; Fludra, A.; Harra, L.; Hassler, D.; Heinzel, P.; Howard, R. A.; Krucker, S.; Livi, S. A.; Long, D.; Louarn, P.; Maksimovic, M.; Mueller, D.; Owen, C. J.; Peter, H.; Rochus, P. L.; Rodriguez-Pacheco, J.; Romoli, M.; Schühle, U.; Solanki, S. K.; Teriaca, L.; Wimmer-Schweingruber, R. F.; Zouganelis, Y.; Laker, R. Bibcode: 2020AGUFMSH038..10H Altcode: A key science goal of the Solar Orbiter mission is to make connections between phenomena on the Sun and their manifestations in interplanetary space. To that end, the spacecraft carries a carefully tailored payload of six remote sensing instruments and four making in situ measurements. During June 2020, while the spacecraft was around 0.5 AU from the Sun, the remote sensing instruments operated for several days. While this was primarily an engineering activity, the resulting observations provided outstanding measurements and represent the ideal first opportunity to investigate the potential for making connections between the remote sensing and in situ payloads on Solar Orbiter.

We present a preliminary analysis of the available remote sensing and in situ observations, showing how connections can be made, and discuss the potential for further, more precise mapping to be performed as the mission progresses. Title: First Images and Initial In-Flight Performance of the Extreme Ultraviolet Imager On-Board Solar Orbiter. Authors: Auchere, F.; Gissot, S.; Teriaca, L.; Berghmans, D.; Harra, L.; Long, D.; Rochus, P. L.; Smith, P.; Schühle, U.; Stegen, K.; Aznar Cuadrado, R.; Heerlein, K.; Kraaikamp, E.; Verbeeck, C. Bibcode: 2020AGUFMSH0360025A Altcode: The Extreme Ultraviolet Imager (EUI) on board Solar Orbiter is composed of two High Resolution Imagers working at 121.6 (HRI-LYA, H I, chromosphere) and 17.4 nm (HRI-EUV, Fe IX/X, corona) and one dual-band Full Sun Imager (FSI) working at 30.4 nm (He II, transition region) and 17.4 nm (Fe IX/X, corona). During the commissioning period following the launch of Solar Orbiter and two and a half months of outgassing, EUI acquired its first solar images on May 12th, 2020 at about 0.67 AU. Most of the capabilities of the instrument have been tested during the following weeks, which revealed excellent overall performance. HRI-EUV already provided images with an angular resolution equivalent to ~0.6" (2 pixels) at 1 A.U. HRI-LYA will routinely provide images of the Sun at Lyman alpha, which have been otherwise relatively rare, with sub-second cadence capability. FSI will provide context for connection science but it will also explore regions of the corona never imaged before at EUV wavelengths, owing to its 3.8° field of view. EUI uses a complex on-board image processing system including advanced image compression and event detection algorithms. In particular, commissioning tests confirm the good performance of the compression, which is critical given the limited total telemetry volume imposed by the mission profile. In this paper, we present the main characteristics of the first images taken in each channel and we provide an initial assessment of the in-flight performance. Title: First results from combined EUI and SPICE observations of Lyman lines of Hydrogen and He II Authors: Teriaca, L.; Aznar Cuadrado, R.; Giunta, A. S.; Grundy, T.; Parenti, S.; Auchere, F.; Vial, J. C.; Fludra, A.; Berghmans, D.; Carlsson, M.; Harra, L.; Hassler, D.; Long, D.; Peter, H.; Rochus, P. L.; Schühle, U.; Buchlin, E.; Caldwell, M.; Caminade, S.; DeForest, C.; Fredvik, T.; Gissot, S.; Heerlein, K.; Janvier, M.; Kraaikamp, E.; Kucera, T. A.; Mueller, D.; Schmutz, W. K.; Sidher, S.; Smith, P.; Stegen, K.; Thompson, W. T.; Verbeeck, C.; Williams, D.; Young, P. R. Bibcode: 2020AGUFMSH0360003T Altcode: The Solar Orbiter spacecraft carries a powerful set of remote sensing instruments that allow studying the solar atmosphere with unprecedented diagnostic capabilities. Many such diagnostics require the simultaneous usage of more than one instrument. One example of that is the capability, for the first time, to obtain (near) simultaneous spatially resolved observations of the emission from the first three lines of the Lyman series of hydrogen and of He II Lyman alpha. In fact, the SPectral Imaging of the Coronal Environment (SPICE) spectrometer can observe the Lyman beta and gamma lines in its long wavelength (SPICE-LW) channel, the High Resolution Lyman Alpha (HRI-LYA) telescope of the Extreme Ultraviolet Imager (EUI) acquires narrow band images in the Lyman alpha line while the Full Disk Imager (FSI) of EUI can take images dominated by the Lyman alpha line of ionized Helium at 30.4 nm (FSI-304). Being hydrogen and helium the main components of our star, these very bright transitions play an important role in the energy budget of the outer atmosphere via radiative losses and the measurement of their profiles and radiance ratios is a fundamental constraint to any comprehensive modelization effort of the upper solar chromosphere and transition region. Additionally, monitoring their average ratios can serve as a check out for the relative radiometric performance of the two instruments throughout the mission. Although the engineering data acquired so far are far from ideal in terms of time simultaneity (often only within about 1 h) and line coverage (often only Lyman beta was acquired by SPICE and not always near simultaneous images from all three telescopes are available) the analysis we present here still offers a great opportunity to have a first look at the potential of this diagnostic from the two instruments. In fact, we have identified a series of datasets obtained at disk center and at various positions at the solar limb that allow studying the Lyman alpha to beta radiance ratio and their relation to He II 30.4 as a function of the position on the Sun (disk center versus limb and quiet Sun versus coronal holes). Title: Very high-resolution observations of the solar atmosphere in H I Lyman alpha and Fe IX-X at 17.4 nm as seen by EUI aboard Solar Orbiter Authors: Aznar Cuadrado, R.; Berghmans, D.; Teriaca, L.; Gissot, S.; Schühle, U.; Auchere, F.; Harra, L.; Long, D.; Rochus, P. L.; Heerlein, K.; Kraaikamp, E.; Smith, P.; Stegen, K.; Verbeeck, C. Bibcode: 2020AGUFMSH0360026A Altcode: The Extreme Ultraviolet Imager (EUI) aboard Solar Orbiter consists of three telescopes, the Full Sun Imager (FSI) and two High Resolution Imagers (HRIs). The two HRI telescopes provide images of the base of the corona, near to the chromosphere, and of the 1 million K corona. In fact, the HRI-EUV telescope operates around 17.4 nm to obtain images dominated by emission from lines generated from Fe-IX and X ions, formed at about 1 MK, while the HRI-LYA telescope provides narrow band images dominated by the H I Lyman alpha line at 121.6 nm, formed in the upper chromosphere/lower transition region of the solar atmosphere around 20,000 K. Thus, the two imagers provide a powerful diagnostics of the solar structural organization, in terms of loop hierarchies and connectivity. Here we present an analysis of the first two near-simultaneous (within 15s) high-resolution images of the solar quiet atmosphere obtained near disk center by the two high-resolution telescopes on May 30th 2020, during the commissioning phase of the mission , when Solar Orbiter was at about 0.56 AU from the Sun. Title: Coordination within the remote sensing payload on the Solar Orbiter mission Authors: Auchère, F.; Andretta, V.; Antonucci, E.; Bach, N.; Battaglia, M.; Bemporad, A.; Berghmans, D.; Buchlin, E.; Caminade, S.; Carlsson, M.; Carlyle, J.; Cerullo, J. J.; Chamberlin, P. C.; Colaninno, R. C.; Davila, J. M.; De Groof, A.; Etesi, L.; Fahmy, S.; Fineschi, S.; Fludra, A.; Gilbert, H. R.; Giunta, A.; Grundy, T.; Haberreiter, M.; Harra, L. K.; Hassler, D. M.; Hirzberger, J.; Howard, R. A.; Hurford, G.; Kleint, L.; Kolleck, M.; Krucker, S.; Lagg, A.; Landini, F.; Long, D. M.; Lefort, J.; Lodiot, S.; Mampaey, B.; Maloney, S.; Marliani, F.; Martinez-Pillet, V.; McMullin, D. R.; Müller, D.; Nicolini, G.; Orozco Suarez, D.; Pacros, A.; Pancrazzi, M.; Parenti, S.; Peter, H.; Philippon, A.; Plunkett, S.; Rich, N.; Rochus, P.; Rouillard, A.; Romoli, M.; Sanchez, L.; Schühle, U.; Sidher, S.; Solanki, S. K.; Spadaro, D.; St Cyr, O. C.; Straus, T.; Tanco, I.; Teriaca, L.; Thompson, W. T.; del Toro Iniesta, J. C.; Verbeeck, C.; Vourlidas, A.; Watson, C.; Wiegelmann, T.; Williams, D.; Woch, J.; Zhukov, A. N.; Zouganelis, I. Bibcode: 2020A&A...642A...6A Altcode: Context. To meet the scientific objectives of the mission, the Solar Orbiter spacecraft carries a suite of in-situ (IS) and remote sensing (RS) instruments designed for joint operations with inter-instrument communication capabilities. Indeed, previous missions have shown that the Sun (imaged by the RS instruments) and the heliosphere (mainly sampled by the IS instruments) should be considered as an integrated system rather than separate entities. Many of the advances expected from Solar Orbiter rely on this synergistic approach between IS and RS measurements.
Aims: Many aspects of hardware development, integration, testing, and operations are common to two or more RS instruments. In this paper, we describe the coordination effort initiated from the early mission phases by the Remote Sensing Working Group. We review the scientific goals and challenges, and give an overview of the technical solutions devised to successfully operate these instruments together.
Methods: A major constraint for the RS instruments is the limited telemetry (TM) bandwidth of the Solar Orbiter deep-space mission compared to missions in Earth orbit. Hence, many of the strategies developed to maximise the scientific return from these instruments revolve around the optimisation of TM usage, relying for example on onboard autonomy for data processing, compression, and selection for downlink. The planning process itself has been optimised to alleviate the dynamic nature of the targets, and an inter-instrument communication scheme has been implemented which can be used to autonomously alter the observing modes. We also outline the plans for in-flight cross-calibration, which will be essential to the joint data reduction and analysis.
Results: The RS instrument package on Solar Orbiter will carry out comprehensive measurements from the solar interior to the inner heliosphere. Thanks to the close coordination between the instrument teams and the European Space Agency, several challenges specific to the RS suite were identified and addressed in a timely manner. Title: The Solar Orbiter Science Activity Plan. Translating solar and heliospheric physics questions into action Authors: Zouganelis, I.; De Groof, A.; Walsh, A. P.; Williams, D. R.; Müller, D.; St Cyr, O. C.; Auchère, F.; Berghmans, D.; Fludra, A.; Horbury, T. S.; Howard, R. A.; Krucker, S.; Maksimovic, M.; Owen, C. J.; Rodríguez-Pacheco, J.; Romoli, M.; Solanki, S. K.; Watson, C.; Sanchez, L.; Lefort, J.; Osuna, P.; Gilbert, H. R.; Nieves-Chinchilla, T.; Abbo, L.; Alexandrova, O.; Anastasiadis, A.; Andretta, V.; Antonucci, E.; Appourchaux, T.; Aran, A.; Arge, C. N.; Aulanier, G.; Baker, D.; Bale, S. D.; Battaglia, M.; Bellot Rubio, L.; Bemporad, A.; Berthomier, M.; Bocchialini, K.; Bonnin, X.; Brun, A. S.; Bruno, R.; Buchlin, E.; Büchner, J.; Bucik, R.; Carcaboso, F.; Carr, R.; Carrasco-Blázquez, I.; Cecconi, B.; Cernuda Cangas, I.; Chen, C. H. K.; Chitta, L. P.; Chust, T.; Dalmasse, K.; D'Amicis, R.; Da Deppo, V.; De Marco, R.; Dolei, S.; Dolla, L.; Dudok de Wit, T.; van Driel-Gesztelyi, L.; Eastwood, J. P.; Espinosa Lara, F.; Etesi, L.; Fedorov, A.; Félix-Redondo, F.; Fineschi, S.; Fleck, B.; Fontaine, D.; Fox, N. J.; Gandorfer, A.; Génot, V.; Georgoulis, M. K.; Gissot, S.; Giunta, A.; Gizon, L.; Gómez-Herrero, R.; Gontikakis, C.; Graham, G.; Green, L.; Grundy, T.; Haberreiter, M.; Harra, L. K.; Hassler, D. M.; Hirzberger, J.; Ho, G. C.; Hurford, G.; Innes, D.; Issautier, K.; James, A. W.; Janitzek, N.; Janvier, M.; Jeffrey, N.; Jenkins, J.; Khotyaintsev, Y.; Klein, K. -L.; Kontar, E. P.; Kontogiannis, I.; Krafft, C.; Krasnoselskikh, V.; Kretzschmar, M.; Labrosse, N.; Lagg, A.; Landini, F.; Lavraud, B.; Leon, I.; Lepri, S. T.; Lewis, G. R.; Liewer, P.; Linker, J.; Livi, S.; Long, D. M.; Louarn, P.; Malandraki, O.; Maloney, S.; Martinez-Pillet, V.; Martinovic, M.; Masson, A.; Matthews, S.; Matteini, L.; Meyer-Vernet, N.; Moraitis, K.; Morton, R. J.; Musset, S.; Nicolaou, G.; Nindos, A.; O'Brien, H.; Orozco Suarez, D.; Owens, M.; Pancrazzi, M.; Papaioannou, A.; Parenti, S.; Pariat, E.; Patsourakos, S.; Perrone, D.; Peter, H.; Pinto, R. F.; Plainaki, C.; Plettemeier, D.; Plunkett, S. P.; Raines, J. M.; Raouafi, N.; Reid, H.; Retino, A.; Rezeau, L.; Rochus, P.; Rodriguez, L.; Rodriguez-Garcia, L.; Roth, M.; Rouillard, A. P.; Sahraoui, F.; Sasso, C.; Schou, J.; Schühle, U.; Sorriso-Valvo, L.; Soucek, J.; Spadaro, D.; Stangalini, M.; Stansby, D.; Steller, M.; Strugarek, A.; Štverák, Š.; Susino, R.; Telloni, D.; Terasa, C.; Teriaca, L.; Toledo-Redondo, S.; del Toro Iniesta, J. C.; Tsiropoula, G.; Tsounis, A.; Tziotziou, K.; Valentini, F.; Vaivads, A.; Vecchio, A.; Velli, M.; Verbeeck, C.; Verdini, A.; Verscharen, D.; Vilmer, N.; Vourlidas, A.; Wicks, R.; Wimmer-Schweingruber, R. F.; Wiegelmann, T.; Young, P. R.; Zhukov, A. N. Bibcode: 2020A&A...642A...3Z Altcode: 2020arXiv200910772Z Solar Orbiter is the first space mission observing the solar plasma both in situ and remotely, from a close distance, in and out of the ecliptic. The ultimate goal is to understand how the Sun produces and controls the heliosphere, filling the Solar System and driving the planetary environments. With six remote-sensing and four in-situ instrument suites, the coordination and planning of the operations are essential to address the following four top-level science questions: (1) What drives the solar wind and where does the coronal magnetic field originate?; (2) How do solar transients drive heliospheric variability?; (3) How do solar eruptions produce energetic particle radiation that fills the heliosphere?; (4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? Maximising the mission's science return requires considering the characteristics of each orbit, including the relative position of the spacecraft to Earth (affecting downlink rates), trajectory events (such as gravitational assist manoeuvres), and the phase of the solar activity cycle. Furthermore, since each orbit's science telemetry will be downloaded over the course of the following orbit, science operations must be planned at mission level, rather than at the level of individual orbits. It is important to explore the way in which those science questions are translated into an actual plan of observations that fits into the mission, thus ensuring that no opportunities are missed. First, the overarching goals are broken down into specific, answerable questions along with the required observations and the so-called Science Activity Plan (SAP) is developed to achieve this. The SAP groups objectives that require similar observations into Solar Orbiter Observing Plans, resulting in a strategic, top-level view of the optimal opportunities for science observations during the mission lifetime. This allows for all four mission goals to be addressed. In this paper, we introduce Solar Orbiter's SAP through a series of examples and the strategy being followed. Title: Observations of the Solar Corona from Space Authors: Antonucci, Ester; Harra, Louise; Susino, Roberto; Telloni, Daniele Bibcode: 2020SSRv..216..117A Altcode: Space observations of the atmosphere of the Sun, obtained in half a century of dedicated space missions, provide a well established picture of the medium and large-scale solar corona, which is highly variable with the level of solar activity through a solar cycle and evolves with the long-term evolution of the magnetic cycles. In this review, we summarize the physical properties and dynamics of the medium and large-scale corona, consisting primarily of active regions, streamers and coronal holes; describe the dependence of coronal patterns on the magnetic field patterns changing through the solar cycle and the properties of the regions of open magnetic flux channeling the solar wind; the ubiquitous presence of fluctuations in the outer corona; the rotational properties of the large-scale corona; and the persistent hemispheric asymmetries in the emergence of magnetic fields and the distribution of the coronal emission. Title: Understanding the origins of the heliosphere: integrating observations and measurements from Parker Solar Probe, Solar Orbiter, and other space- and ground-based observatories Authors: Velli, M.; Harra, L. K.; Vourlidas, A.; Schwadron, N.; Panasenco, O.; Liewer, P. C.; Müller, D.; Zouganelis, I.; St Cyr, O. C.; Gilbert, H.; Nieves-Chinchilla, T.; Auchère, F.; Berghmans, D.; Fludra, A.; Horbury, T. S.; Howard, R. A.; Krucker, S.; Maksimovic, M.; Owen, C. J.; Rodríguez-Pacheco, J.; Romoli, M.; Solanki, S. K.; Wimmer-Schweingruber, R. F.; Bale, S.; Kasper, J.; McComas, D. J.; Raouafi, N.; Martinez-Pillet, V.; Walsh, A. P.; De Groof, A.; Williams, D. Bibcode: 2020A&A...642A...4V Altcode: Context. The launch of Parker Solar Probe (PSP) in 2018, followed by Solar Orbiter (SO) in February 2020, has opened a new window in the exploration of solar magnetic activity and the origin of the heliosphere. These missions, together with other space observatories dedicated to solar observations, such as the Solar Dynamics Observatory, Hinode, IRIS, STEREO, and SOHO, with complementary in situ observations from WIND and ACE, and ground based multi-wavelength observations including the DKIST observatory that has just seen first light, promise to revolutionize our understanding of the solar atmosphere and of solar activity, from the generation and emergence of the Sun's magnetic field to the creation of the solar wind and the acceleration of solar energetic particles.
Aims: Here we describe the scientific objectives of the PSP and SO missions, and highlight the potential for discovery arising from synergistic observations. Here we put particular emphasis on how the combined remote sensing and in situ observations of SO, that bracket the outer coronal and inner heliospheric observations by PSP, may provide a reconstruction of the solar wind and magnetic field expansion from the Sun out to beyond the orbit of Mercury in the first phases of the mission. In the later, out-of-ecliptic portions of the SO mission, the solar surface magnetic field measurements from SO and the multi-point white-light observations from both PSP and SO will shed light on the dynamic, intermittent solar wind escaping from helmet streamers, pseudo-streamers, and the confined coronal plasma, and on solar energetic particle transport.
Methods: Joint measurements during PSP-SO alignments, and magnetic connections along the same flux tube complemented by alignments with Earth, dual PSP-Earth, and SO-Earth, as well as with STEREO-A, SOHO, and BepiColumbo will allow a better understanding of the in situ evolution of solar-wind plasma flows and the full three-dimensional distribution of the solar wind from a purely observational point of view. Spectroscopic observations of the corona, and optical and radio observations, combined with direct in situ observations of the accelerating solar wind will provide a new foundation for understanding the fundamental physical processes leading to the energy transformations from solar photospheric flows and magnetic fields into the hot coronal plasma and magnetic fields and finally into the bulk kinetic energy of the solar wind and solar energetic particles.
Results: We discuss the initial PSP observations, which already provide a compelling rationale for new measurement campaigns by SO, along with ground- and space-based assets within the synergistic context described above. Title: The Solar Orbiter mission. Science overview Authors: Müller, D.; St. Cyr, O. C.; Zouganelis, I.; Gilbert, H. R.; Marsden, R.; Nieves-Chinchilla, T.; Antonucci, E.; Auchère, F.; Berghmans, D.; Horbury, T. S.; Howard, R. A.; Krucker, S.; Maksimovic, M.; Owen, C. J.; Rochus, P.; Rodriguez-Pacheco, J.; Romoli, M.; Solanki, S. K.; Bruno, R.; Carlsson, M.; Fludra, A.; Harra, L.; Hassler, D. M.; Livi, S.; Louarn, P.; Peter, H.; Schühle, U.; Teriaca, L.; del Toro Iniesta, J. C.; Wimmer-Schweingruber, R. F.; Marsch, E.; Velli, M.; De Groof, A.; Walsh, A.; Williams, D. Bibcode: 2020A&A...642A...1M Altcode: 2020arXiv200900861M
Aims: Solar Orbiter, the first mission of ESA's Cosmic Vision 2015-2025 programme and a mission of international collaboration between ESA and NASA, will explore the Sun and heliosphere from close up and out of the ecliptic plane. It was launched on 10 February 2020 04:03 UTC from Cape Canaveral and aims to address key questions of solar and heliospheric physics pertaining to how the Sun creates and controls the Heliosphere, and why solar activity changes with time. To answer these, the mission carries six remote-sensing instruments to observe the Sun and the solar corona, and four in-situ instruments to measure the solar wind, energetic particles, and electromagnetic fields. In this paper, we describe the science objectives of the mission, and how these will be addressed by the joint observations of the instruments onboard.
Methods: The paper first summarises the mission-level science objectives, followed by an overview of the spacecraft and payload. We report the observables and performance figures of each instrument, as well as the trajectory design. This is followed by a summary of the science operations concept. The paper concludes with a more detailed description of the science objectives.
Results: Solar Orbiter will combine in-situ measurements in the heliosphere with high-resolution remote-sensing observations of the Sun to address fundamental questions of solar and heliospheric physics. The performance of the Solar Orbiter payload meets the requirements derived from the mission's science objectives. Its science return will be augmented further by coordinated observations with other space missions and ground-based observatories.

ARRAY(0x207ce98) Title: The Solar Orbiter EUI instrument: The Extreme Ultraviolet Imager Authors: Rochus, P.; Auchère, F.; Berghmans, D.; Harra, L.; Schmutz, W.; Schühle, U.; Addison, P.; Appourchaux, T.; Aznar Cuadrado, R.; Baker, D.; Barbay, J.; Bates, D.; BenMoussa, A.; Bergmann, M.; Beurthe, C.; Borgo, B.; Bonte, K.; Bouzit, M.; Bradley, L.; Büchel, V.; Buchlin, E.; Büchner, J.; Cabé, F.; Cadiergues, L.; Chaigneau, M.; Chares, B.; Choque Cortez, C.; Coker, P.; Condamin, M.; Coumar, S.; Curdt, W.; Cutler, J.; Davies, D.; Davison, G.; Defise, J. -M.; Del Zanna, G.; Delmotte, F.; Delouille, V.; Dolla, L.; Dumesnil, C.; Dürig, F.; Enge, R.; François, S.; Fourmond, J. -J.; Gillis, J. -M.; Giordanengo, B.; Gissot, S.; Green, L. M.; Guerreiro, N.; Guilbaud, A.; Gyo, M.; Haberreiter, M.; Hafiz, A.; Hailey, M.; Halain, J. -P.; Hansotte, J.; Hecquet, C.; Heerlein, K.; Hellin, M. -L.; Hemsley, S.; Hermans, A.; Hervier, V.; Hochedez, J. -F.; Houbrechts, Y.; Ihsan, K.; Jacques, L.; Jérôme, A.; Jones, J.; Kahle, M.; Kennedy, T.; Klaproth, M.; Kolleck, M.; Koller, S.; Kotsialos, E.; Kraaikamp, E.; Langer, P.; Lawrenson, A.; Le Clech', J. -C.; Lenaerts, C.; Liebecq, S.; Linder, D.; Long, D. M.; Mampaey, B.; Markiewicz-Innes, D.; Marquet, B.; Marsch, E.; Matthews, S.; Mazy, E.; Mazzoli, A.; Meining, S.; Meltchakov, E.; Mercier, R.; Meyer, S.; Monecke, M.; Monfort, F.; Morinaud, G.; Moron, F.; Mountney, L.; Müller, R.; Nicula, B.; Parenti, S.; Peter, H.; Pfiffner, D.; Philippon, A.; Phillips, I.; Plesseria, J. -Y.; Pylyser, E.; Rabecki, F.; Ravet-Krill, M. -F.; Rebellato, J.; Renotte, E.; Rodriguez, L.; Roose, S.; Rosin, J.; Rossi, L.; Roth, P.; Rouesnel, F.; Roulliay, M.; Rousseau, A.; Ruane, K.; Scanlan, J.; Schlatter, P.; Seaton, D. B.; Silliman, K.; Smit, S.; Smith, P. J.; Solanki, S. K.; Spescha, M.; Spencer, A.; Stegen, K.; Stockman, Y.; Szwec, N.; Tamiatto, C.; Tandy, J.; Teriaca, L.; Theobald, C.; Tychon, I.; van Driel-Gesztelyi, L.; Verbeeck, C.; Vial, J. -C.; Werner, S.; West, M. J.; Westwood, D.; Wiegelmann, T.; Willis, G.; Winter, B.; Zerr, A.; Zhang, X.; Zhukov, A. N. Bibcode: 2020A&A...642A...8R Altcode: Context. The Extreme Ultraviolet Imager (EUI) is part of the remote sensing instrument package of the ESA/NASA Solar Orbiter mission that will explore the inner heliosphere and observe the Sun from vantage points close to the Sun and out of the ecliptic. Solar Orbiter will advance the "connection science" between solar activity and the heliosphere.
Aims: With EUI we aim to improve our understanding of the structure and dynamics of the solar atmosphere, globally as well as at high resolution, and from high solar latitude perspectives.
Methods: The EUI consists of three telescopes, the Full Sun Imager and two High Resolution Imagers, which are optimised to image in Lyman-α and EUV (17.4 nm, 30.4 nm) to provide a coverage from chromosphere up to corona. The EUI is designed to cope with the strong constraints imposed by the Solar Orbiter mission characteristics. Limited telemetry availability is compensated by state-of-the-art image compression, onboard image processing, and event selection. The imposed power limitations and potentially harsh radiation environment necessitate the use of novel CMOS sensors. As the unobstructed field of view of the telescopes needs to protrude through the spacecraft's heat shield, the apertures have been kept as small as possible, without compromising optical performance. This led to a systematic effort to optimise the throughput of every optical element and the reduction of noise levels in the sensor.
Results: In this paper we review the design of the two elements of the EUI instrument: the Optical Bench System and the Common Electronic Box. Particular attention is also given to the onboard software, the intended operations, the ground software, and the foreseen data products.
Conclusions: The EUI will bring unique science opportunities thanks to its specific design, its viewpoint, and to the planned synergies with the other Solar Orbiter instruments. In particular, we highlight science opportunities brought by the out-of-ecliptic vantage point of the solar poles, the high-resolution imaging of the high chromosphere and corona, and the connection to the outer corona as observed by coronagraphs. Title: The Solaris Solar Polar Mission Authors: Hassler, Donald M.; Newmark, Jeff; Gibson, Sarah; Harra, Louise; Appourchaux, Thierry; Auchere, Frederic; Berghmans, David; Colaninno, Robin; Fineschi, Silvano; Gizon, Laurent; Gosain, Sanjay; Hoeksema, Todd; Kintziger, Christian; Linker, John; Rochus, Pierre; Schou, Jesper; Viall, Nicholeen; West, Matt; Woods, Tom; Wuelser, Jean-Pierre Bibcode: 2020EGUGA..2217703H Altcode: The solar poles are one of the last unexplored regions of the solar system. Although Ulysses flew over the poles in the 1990s, it did not have remote sensing instruments onboard to probe the Sun's polar magnetic field or surface/sub-surface flows.We will discuss Solaris, a proposed Solar Polar MIDEX mission to revolutionize our understanding of the Sun by addressing fundamental questions that can only be answered from a polar vantage point. Solaris uses a Jupiter gravity assist to escape the ecliptic plane and fly over both poles of the Sun to >75 deg. inclination, obtaining the first high-latitude, multi-month-long, continuous remote-sensing solar observations. Solaris will address key outstanding, breakthrough problems in solar physics and fill holes in our scientific understanding that will not be addressed by current missions.With focused science and a simple, elegant mission design, Solaris will also provide enabling observations for space weather research (e.g. polar view of CMEs), and stimulate future research through new unanticipated discoveries. Title: Earth Energy Imbalance Authors: Finsterle, W.; Haberreiter, M.; Harra, L. Bibcode: 2020LPICo2241.5126F Altcode: We will present requirement studies regarding accuracy and precision to successfully measure the Earth's outgoing radiation from the lunar south polar area and discuss the technical challenges to achieve this with an absolute radiometer. Title: Solar physics in the 2020s: DKIST, parker solar probe, and solar orbiter as a multi-messenger constellation Authors: Martinez Pillet, V.; Tritschler, A.; Harra, L.; Andretta, V.; Vourlidas, A.; Raouafi, N.; Alterman, B. L.; Bellot Rubio, L.; Cauzzi, G.; Cranmer, S. R.; Gibson, S.; Habbal, S.; Ko, Y. K.; Lepri, S. T.; Linker, J.; Malaspina, D. M.; Matthews, S.; Parenti, S.; Petrie, G.; Spadaro, D.; Ugarte-Urra, I.; Warren, H.; Winslow, R. Bibcode: 2020arXiv200408632M Altcode: The National Science Foundation (NSF) Daniel K. Inouye Solar Telescope (DKIST) is about to start operations at the summit of Haleakala (Hawaii). DKIST will join the early science phases of the NASA and ESA Parker Solar Probe and Solar Orbiter encounter missions. By combining in-situ measurements of the near-sun plasma environment and detail remote observations of multiple layers of the Sun, the three observatories form an unprecedented multi-messenger constellation to study the magnetic connectivity inside the solar system. This white paper outlines the synergistic science that this multi-messenger suite enables. Title: Serial Flaring in an Active Region: Exploring Why Only One Flare Is Eruptive Authors: Woods, Magnus M.; Inoue, Satoshi; Harra, Louise K.; Matthews, Sarah A.; Kusano, Kanya Bibcode: 2020ApJ...890...84W Altcode: Over a four hour period between 2014 June 12-13 a series of three flares were observed within AR 12087. This sequence of flares started with a non-eruptive M-class flare, followed by a non-eruptive C-class flare, and finally ended with a second C-class flare that had an associated filament eruption. In this paper we combine spectroscopic analysis of Interface Region Imaging Spectrometer observations of the Si IV line during the three flares along with a series of nonlinear force-free field (NLFFF) extrapolations in order to investigate the conditions that lead the final flare to be eruptive. From this analysis it is found to be unlikely that the eruption was triggered by either kink instability or by tether-cutting reconnection, allowing the flux rope to rise into a region where it would be susceptible to the torus instability. The NLFFF modeling does, however, suggest that the overlying magnetic field has a fan-spine topology, raising the possibility that breakout reconnection occurring during the first two flares weakened the overlying field, allowing the flux rope to erupt in the subsequent third flare. Title: Locating Hot Plasma in Small Flares using Spectroscopic Overlappogram Data from the Hinode EUV Imaging Spectrometer Authors: Harra, Louise; Matthews, Sarah; Long, David; Hasegawa, Takahiro; Lee, Kyoung-Sun; Reeves, Katharine K.; Shimizu, Toshifumi; Hara, Hirohisa; Woods, Magnus Bibcode: 2020SoPh..295...34H Altcode: 2020arXiv200302908H One of the key processes associated with the "standard" flare model is chromospheric evaporation, a process during which plasma heated to high temperatures by energy deposition at the flare footpoints is driven upwards into the corona. Despite several decades of study, a number of open questions remain, including the relationship between plasma produced during this process and observations of earlier "superhot" plasma. The Extreme ultraviolet Imaging Spectrometer (EIS) onboard Hinode has a wide slot, which is often used as a flare trigger in the He II emission-line band. Once the intensity passes a threshold level, the study will switch to one focussed on the flaring region. However, when the intensity is not high enough to reach the flare trigger threshold, these datasets are then available during the entire flare period and provide high-cadence spectroscopic observations over a large field of view. We make use of data from two such studies of a C4.7 flare and a C1.6 flare to probe the relationship between hot Fe XXIV plasma and plasmas observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the X-ray Telescope (XRT) to track where the emission comes from and when it begins. The flare trigger slot data used in our analysis has one-minute cadence. Although the spatial and spectral information are merged in the wide-slot data, it is still possible to extract when the hot plasma appears, through the appearance of the Fe Xxiv spectral image. It is also possible to derive spectrally pure Fe XXIV light curves from the EIS data, and compare them with those derived from hard X-rays, enabling a full exploration of the evolution of hot emission. The Fe XXIV emission peaks just after the peak in the hard X-ray lightcurve; consistent with an origin in the evaporation of heated plasma following the transfer of energy to the lower atmosphere. A peak was also found for the C4.7 flare in the RHESSI peak temperature, which occurred before the hard X-rays peaked. This suggests that the first peak in hot-plasma emission is likely to be directly related to the energy-release process. Title: A Two-Sided-Loop X-Ray Solar Coronal Jet and a Sudden Photospheric Magnetic-field Change, Both Driven by a Minifilament Eruption Authors: Sterling, A. C.; Harra, L. K.; Moore, R. L.; Falconer, D. A. Bibcode: 2019AGUFMSH11D3382S Altcode: Most of the commonly discussed solar coronal jets are of the type consisting of a

single spire extending approximately vertically from near the solar surface into the

corona. Recent research shows that eruption of a miniature filament (minifilament)

drives at least many such single-spire jets, and concurrently generates a miniflare at the

eruption site. A different type of coronal jet, identified in X-ray images during the

Yohkoh era, are two-sided-loop jets, which extend from a central excitation location

in opposite directions, along two opposite low-lying coronal loops that are more-or-less

horizontal to the surface. We observe such a two-sided-loop jet from the edge of active

region (AR) 12473, using data from Hinode XRT and EIS, and SDO AIA and HMI. Similar

to single-spire jets, this two-sided-loop jet results from eruption of a minifilament, which

accelerates to over 140 km/s before abruptly stopping upon striking overlying

nearly-horizontal magnetic field at ∼ 30,000 km altitude and producing the two-sided-loop

jet via interchange reconnection. Analysis of EIS raster scans show that a hot

brightening, consistent with a small flare, develops in the aftermath of the eruption,

and that Doppler motions (∼ 40 km/s) occur near the jet-formation region. As with

many single-spire jets, the trigger of the eruption here is apparently magnetic

flux cancelation, which occurs at a rate of ∼ 4×10^18 Mx/hr, comparable to the rate

observed in some single-spire AR jets. An apparent increase in the (line-of-sight)

flux occurs within minutes of onset of the minifilament eruption, consistent with the

apparent increase being due to a rapid reconfiguration of low-lying magnetic field

during the minifilament eruption. Details appear in Sterling et al. (2019, ApJ, 871, 220). Title: Genesis and impulsive evolution of the fast CME associated with the X8.2 flare on 2017 September 10 Authors: Veronig, A.; Podladchikova, T.; Dissauer, K.; Temmer, M.; Seaton, D. B.; Long, D.; Guo, J.; Vrsnak, B.; Harra, L. K.; Kliem, B. Bibcode: 2019AGUFMSH13A..02V Altcode: The X8.2 event of 2017 September 10 provides unique observations to study the genesis, magnetic morphology, impulsive dynamics and shock formation in a very fast coronal mass ejection (CME). As will be discussed in this presentation, fundamental insight in the processes of magnetic reconnection, CME acceleration and shock formation are provided through EUV observations of the middle corona.

Combining the large field-of-view and high-cadence imagery from GOES-16/SUVI and SDO/AIA EUV, respectively, we identify a hot (T ≈ 10-15 MK) bright rim around a quickly expanding cavity, embedded inside a much larger CME shell (T ≈ 1-2 MK). The CME shell develops from a dense set of large AR loops (>0.5Rs) and seamlessly evolves into the CME front observed in LASCO C2. The strong lateral overexpansion of the CME shell acts as a piston initiating the fast and globally propagating EUV shock wave. The hot cavity rim is demonstrated to be a manifestation of the dominantly poloidal flux and frozen-in plasma added to the rising flux rope by magnetic reconnection in the current sheet beneath. The same structure is later observed as the core of the white-light CME, challenging the traditional interpretation of the CME three-part morphology (Veronig et al. 2018).

The large amount of added magnetic flux suggested by these observations can explain the extreme accelerations of the radial and lateral expansion of the CME shell and cavity, all reaching values up to 5-10 km s-2. The acceleration peaks occur simultaneously with the first RHESSI 100-300 keV hard X-ray burst of the associated flare, further underlining the importance of the reconnection process for the impulsive CME evolution in the low and middle corona. Title: The Solar Orbiter EUI instrument: The Extreme Ultraviolet Imager Authors: Rochus, P. L.; Auchere, F.; Berghmans, D.; Harra, L.; Schmutz, W. K.; Schühle, U. Bibcode: 2019AGUFMSH21D3291R Altcode: The Extreme Ultraviolet Imager (EUI) is part of the remote sensing instrument package of the ESA/NASA Solar Orbiter mission that will explore the inner heliosphere and observe the Sun from vantage points close to the Sun and out-of-the-ecliptic.

EUI aims at improving our understanding of the structure and dynamics of the solar atmosphere. EUI will take images of the solar atmosphere, globally as well as at high resolution, and from high solar latitude perspectives.

EUI consists of 3 telescopes that are optimized to image in Lyman-a and EUV 17.4nm and 30.4 nm to provide a coverage from chromosphere up to corona. EUI is designed to cope with the strong constraints that Solar Orbiter has as a deep space mission. Limited telemetry availability is compensated by state-of-the-art image compression, on board image processing and event selection. The imposed power limitations and potentially harsh radiation environment lead to the usage of novel CMOS sensors. As the unobstructed field of view of the telescopes needs to protrude through the spacecraft heat shield, the apertures were kept as small as possible. This lead to a systematic effort to optimize the throughput of every optical element and the reduction of noise levels in the sensor.

In this paper we review the design of the two elements of the EUI instrument: the Optical Bench System and the Common Electronic Box. Particular attention is also given to the on board software, the intended operations, the ground software and the foreseen data products.

EUI will bring unique science opportunities thanks to its specific design, its viewpoint and thanks to the planned synergies with the other Solar Orbiter instruments. We highlight in particular science opportunities brought by the out-of-ecliptic vantage point of the solar poles, the high resolution imaging of the high chromosphere and corona, and the connection to the outer corona as observed by coronagraphs. Title: Active Region Modulation of Coronal Hole Solar Wind Authors: Macneil, Allan R.; Owen, Christopher J.; Baker, Deborah; Brooks, David H.; Harra, Louise K.; Long, David M.; Wicks, Robert T. Bibcode: 2019ApJ...887..146M Altcode: Active regions (ARs) are a candidate source of the slow solar wind (SW), the origins of which are a topic of ongoing research. We present a case study that examines the processes by which SW is modulated in the presence of an AR in the vicinity of the SW source. We compare properties of SW associated with a coronal hole (CH)-quiet Sun boundary to SW associated with the same CH but one Carrington rotation later, when this region bordered the newly emerged NOAA AR 12532. Differences found in a range of in situ parameters are compared between these rotations in the context of source region mapping and remote sensing observations. Marked changes exist in the structure and composition of the SW, which we attribute to the influence of the AR on SW production from the CH boundary. These unique observations suggest that the features that emerge in the AR-associated wind are consistent with an increased occurrence of interchange reconnection during SW production, compared with the initial quiet Sun case. Title: Achievements of Hinode in the first eleven years Authors: Hinode Review Team; Al-Janabi, Khalid; Antolin, Patrick; Baker, Deborah; Bellot Rubio, Luis R.; Bradley, Louisa; Brooks, David H.; Centeno, Rebecca; Culhane, J. Leonard; Del Zanna, Giulio; Doschek, George A.; Fletcher, Lyndsay; Hara, Hirohisa; Harra, Louise K.; Hillier, Andrew S.; Imada, Shinsuke; Klimchuk, James A.; Mariska, John T.; Pereira, Tiago M. D.; Reeves, Katharine K.; Sakao, Taro; Sakurai, Takashi; Shimizu, Toshifumi; Shimojo, Masumi; Shiota, Daikou; Solanki, Sami K.; Sterling, Alphonse C.; Su, Yingna; Suematsu, Yoshinori; Tarbell, Theodore D.; Tiwari, Sanjiv K.; Toriumi, Shin; Ugarte-Urra, Ignacio; Warren, Harry P.; Watanabe, Tetsuya; Young, Peter R. Bibcode: 2019PASJ...71R...1H Altcode: Hinode is Japan's third solar mission following Hinotori (1981-1982) and Yohkoh (1991-2001): it was launched on 2006 September 22 and is in operation currently. Hinode carries three instruments: the Solar Optical Telescope, the X-Ray Telescope, and the EUV Imaging Spectrometer. These instruments were built under international collaboration with the National Aeronautics and Space Administration and the UK Science and Technology Facilities Council, and its operation has been contributed to by the European Space Agency and the Norwegian Space Center. After describing the satellite operations and giving a performance evaluation of the three instruments, reviews are presented on major scientific discoveries by Hinode in the first eleven years (one solar cycle long) of its operation. This review article concludes with future prospects for solar physics research based on the achievements of Hinode. Title: The Solar-C_EUVST mission Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kawate, Tomoko; Ichimoto, Kiyoshi; Suematsu, Yoshinori; Hara, Hirohisa; Katsukawa, Yukio; Kubo, Masahito; Toriumi, Shin; Watanabe, Tetsuya; Yokoyama, Takaaki; Korendyke, Clarence M.; Warren, Harry P.; Tarbell, Ted; De Pontieu, Bart; Teriaca, Luca; Schühle, Udo H.; Solanki, Sami; Harra, Louise K.; Matthews, Sarah; Fludra, A.; Auchère, F.; Andretta, V.; Naletto, G.; Zhukov, A. Bibcode: 2019SPIE11118E..07S Altcode: Solar-C EUVST (EUV High-Throughput Spectroscopic Telescope) is a solar physics mission concept that was selected as a candidate for JAXA competitive M-class missions in July 2018. The onboard science instrument, EUVST, is an EUV spectrometer with slit-jaw imaging system that will simultaneously observe the solar atmosphere from the photosphere/chromosphere up to the corona with seamless temperature coverage, high spatial resolution, and high throughput for the first time. The mission is designed to provide a conclusive answer to the most fundamental questions in solar physics: how fundamental processes lead to the formation of the solar atmosphere and the solar wind, and how the solar atmosphere becomes unstable, releasing the energy that drives solar flares and eruptions. The entire instrument structure and the primary mirror assembly with scanning and tip-tilt fine pointing capability for the EUVST are being developed in Japan, with spectrograph and slit-jaw imaging hardware and science contributions from US and European countries. The mission will be launched and installed in a sun-synchronous polar orbit by a JAXA Epsilon vehicle in 2025. ISAS/JAXA coordinates the conceptual study activities during the current mission definition phase in collaboration with NAOJ and other universities. The team is currently working towards the JAXA final down-selection expected at the end of 2019, with strong support from US and European colleagues. The paper provides an overall description of the mission concept, key technologies, and the latest status. Title: A Two-Sided-Loop X-Ray Solar Coronal Jet and a Sudden Photospheric Magnetic-field Change, Both Driven by a Minifilament Eruption Authors: Sterling, Alphonse C.; Harra, Louise; Moore, Ronald L.; Falconer, David Bibcode: 2019AAS...23431701S Altcode: Most of the commonly discussed solar coronal jets are of the type consisting of a single spire extending approximately vertically from near the solar surface into the corona. Recent research shows that eruption of a miniature filament (minifilament) drives at least many such single-spire jets, and concurrently generates a miniflare at the eruption site. A different type of coronal jet, identified in X-ray images during the Yohkoh era, are two-sided-loop jets, which extend from a central excitation location in opposite directions, along two opposite low-lying coronal loops that are more-or-less horizontal to the surface. We observe such a two-sided-loop jet from the edge of active region (AR) 12473, using data from Hinode XRT and EIS, and SDO AIA and HMI. Similar to single-spire jets, this two-sided-loop jet results from eruption of a minifilament, which accelerates to over 140 km/s before abruptly stopping upon striking overlying nearly-horizontal magnetic field at ∼30,000 km altitude and producing the two-sided-loop jet via interchange reconnection. Analysis of EIS raster scans show that a hot brightening, consistent with a small flare, develops in the aftermath of the eruption, and that Doppler motions (∼40 km/s) occur near the jet-formation region. As with many single-spire jets, the trigger of the eruption here is apparently magnetic flux cancelation, which occurs at a rate of ∼4×1018 Mx/hr, comparable to the rate observed in some single-spire AR jets. An apparent increase in the (line-of-sight) flux occurs within minutes of onset of the minifilament eruption, consistent with the apparent increase being due to a rapid reconfiguration of low-lying magnetic field during the minifilament eruption. Details appear in Sterling et al. (2019, ApJ, 871, 220). Title: Comprehensive Determination of the Hinode/EIS Roll Angle Authors: Pelouze, Gabriel; Auchère, Frédéric; Bocchialini, Karine; Harra, Louise; Baker, Deborah; Warren, Harry P.; Brooks, David H.; Mariska, John T. Bibcode: 2019SoPh..294...59P Altcode: 2019arXiv190311923P We present a new coalignment method for the EUV Imaging Spectrometer (EIS) on board the Hinode spacecraft. In addition to the pointing offset and spacecraft jitter, this method determines the roll angle of the instrument, which has never been systematically measured, and which is therefore usually not corrected. The optimal pointing for EIS is computed by maximizing the cross-correlations of the Fe XII 195.119 Å line with images from the 193 Å band of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). By coaligning 3336 rasters with high signal-to-noise ratio, we estimate the rotation angle between EIS and AIA and explore the distribution of its values. We report an average value of (−0.387±0.007 ) ∘. We also provide a software implementation of this method that can be used to coalign any EIS raster. Title: Genesis, magnetic morphology and impulsive evolution of the coronal mass ejection associated with the X8.2 flare on 2017 September 10 Authors: Veronig, Astrid; Podladchikova, Tatiana; Dissauer, Karin; Temmer, Manuela; Seaton, Daniel; Long, David; Guo, Jingnan; Vrsnak, Bojan; Harra, Louise; Kliem, Bernhard Bibcode: 2019EGUGA..21.9243V Altcode: The extreme X8.2 event of 2017 September 10 provides unique observations to study the genesis, magnetic morphology, impulsive dynamics and shock formation in a very fast coronal mass ejection (CME). Combining GOES-16/SUVI and SDO/AIA EUV imagery, we identify a hot (T ≈ 10-15 MK) bright rim around a quickly expanding cavity, embedded inside a much larger CME shell (T ≈ 1-2 MK). The CME shell develops from a dense set of large AR loops (>0.5Rs) and seamlessly evolves into the CME front observed in LASCO C2. The strong lateral overexpansion of the CME shell acts as a piston initiating the fast EUV shock wave. The hot cavity rim is demonstrated to be a manifestation of the dominantly poloidal flux and frozen-in plasma added to the rising flux rope by magnetic reconnection in the current sheet beneath. The same structure is later observed as the core of the white-light CME, challenging the traditional interpretation of the CME three-part morphology. The large amount of added magnetic flux suggested by these observations explains the extreme accelerations of the radial and lateral expansion of the CME shell and cavity, all reaching values up to 5-10 km s-2. The acceleration peaks occur simultaneously with the first RHESSI 100-300 keV hard X-ray burst of the associated flare, further underlining the importance of the reconnection process for the impulsive CME evolution. Finally, the much higher radial propagation speed of the flux rope in relation to the CME shell causes a distinct deformation of the white-light CME front and shock. Title: Origins and Properties of Active Region Solar Wind Authors: Macneil, Allan; Owen, Christopher; Baker, Deborah; Harra, Louise; Long, David; Wicks, Robert Bibcode: 2019EGUGA..21.9712M Altcode: A primary goal of both the recently-launched Parker Solar Probe (PSP) and upcoming Solar Orbiter (SolO) missions is to identify and explain the origins of the solar wind. Recent studies have suggested that active regions (ARs) are the source of a significant fraction of the solar wind. Of particular interest is the AR contribution to the slow solar wind; the origins of which are still largely unknown. We present a case study of a rare opportunity to explain how the solar wind may emerge from, or be otherwise altered by, an AR, and also to identify the properties resulting from such a process. A simple backmapping procedure is applied to combine EUV remote sensing (SDO-AIA and Hinode-EIS) and in situ (ACE and WIND) observations of the corona and solar wind for two consecutive Carrington rotations. Contrasting observations during the latter rotation, when an AR is present at a trailing coronal hole (CH) boundary, to those during the former, when the AR is yet to emerge, allows us to isolate the influence of the AR on the solar wind from the CH boundary in a unique way. This observational strategy is particularly timely, as the combination of in situ and remote sensing observations, often from multiple spacecraft, will be critical to the identification of solar wind origins with PSP and SolO. With this methodology we find that, as a result of the presence of the AR, there is significant alteration of solar wind features such as velocity, composition, structure, and magnetic field orientation. The changes observed when the AR is present are consistent with the occurrence of interchange reconnection between AR and CH magnetic fields, which we argue is the likely mechanism by which the AR solar wind is produced. Title: A Two-sided Loop X-Ray Solar Coronal Jet Driven by a Minifilament Eruption Authors: Sterling, Alphonse C.; Harra, Louise K.; Moore, Ronald L.; Falconer, David A. Bibcode: 2019ApJ...871..220S Altcode: 2018arXiv181105557S Most of the commonly discussed solar coronal jets are the type that consist of a single spire extending approximately vertically from near the solar surface into the corona. Recent research supports that eruption of a miniature filament (minifilament) drives many such single-spire jets and concurrently generates a miniflare at the eruption site. A different type of coronal jet, identified in X-ray images during the Yohkoh era, are two-sided loop jets, which extend from a central excitation location in opposite directions, along low-lying coronal loops that are more-or-less horizontal to the surface. We observe such a two-sided loop jet from the edge of active region (AR) 12473, using data from Hinode X-Ray Telescope (XRT) and Extreme Ultraviolet Imaging Spectrometer (EIS), and from Solar Dynamics Observatory’s (SDO) Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI). Similar to single-spire jets, this two-sided loop jet results from eruption of a minifilament, which accelerates to over 140 km s-1 before abruptly stopping after striking an overlying nearly horizontal-loop field at ∼30,000 km in altitude and producing the two-sided loop jet. An analysis of EIS raster scans shows that a hot brightening, consistent with a small flare, develops in the aftermath of the eruption, and that Doppler motions (∼40 km s-1) occur near the jet formation region. As with many single-spire jets, the magnetic trigger here is apparently flux cancelation, which occurs at a rate of ∼4 × 1018 Mx hr-1, broadly similar to the rates observed in some single-spire quiet-Sun and AR jets. An apparent increase in the (line-of-sight) flux occurs within minutes of the onset of the minifilament eruption, consistent with the apparent increase being due to a rapid reconfiguration of low-lying fields during and soon after the minifilament-eruption onset. Title: Genesis and Impulsive Evolution of the 2017 September 10 Coronal Mass Ejection Authors: Veronig, Astrid M.; Podladchikova, Tatiana; Dissauer, Karin; Temmer, Manuela; Seaton, Daniel B.; Long, David; Guo, Jingnan; Vršnak, Bojan; Harra, Louise; Kliem, Bernhard Bibcode: 2018ApJ...868..107V Altcode: 2018arXiv181009320V The X8.2 event of 2017 September 10 provides unique observations to study the genesis, magnetic morphology, and impulsive dynamics of a very fast coronal mass ejection (CME). Combining GOES-16/SUVI and SDO/AIA EUV imagery, we identify a hot (T ≈ 10-15 MK) bright rim around a quickly expanding cavity, embedded inside a much larger CME shell (T ≈ 1-2 MK). The CME shell develops from a dense set of large AR loops (≳0.5R s ) and seamlessly evolves into the CME front observed in LASCO C2. The strong lateral overexpansion of the CME shell acts as a piston initiating the fast EUV wave. The hot cavity rim is demonstrated to be a manifestation of the dominantly poloidal flux and frozen-in plasma added to the rising flux rope by magnetic reconnection in the current sheet beneath. The same structure is later observed as the core of the white-light CME, challenging the traditional interpretation of the CME three-part morphology. The large amount of added magnetic flux suggested by these observations explains the extreme accelerations of the radial and lateral expansion of the CME shell and cavity, all reaching values of 5-10 km s-2. The acceleration peaks occur simultaneously with the first RHESSI 100-300 keV hard X-ray burst of the associated flare, further underlining the importance of the reconnection process for the impulsive CME evolution. Finally, the much higher radial propagation speed of the flux rope in relation to the CME shell causes a distinct deformation of the white-light CME front and shock. Title: The EUI instrument onboard Solar Orbiter: the EUV corona imaged differently Authors: Berghmans, David; Rochus, Pierre; Auchère, Frédéric; Harra, Louise; Schmutz, Werner; Schühle, Udo Bibcode: 2018csc..confE..73B Altcode: The ESA Solar Orbiter mission is designed to determine how the Sun creates and controls the heliosphere. The spacecraft will bring a combination of in situ and remote sensing instruments out of the ecliptic (>30°) and close to the sun (0.3 solar-radii). The launch of Solar Orbiter is expected (not earlier than) Feb 2019. The Extreme Ultraviolet Imager is part of the remote-sensing package of Solar Orbiter, to be operating during 3 ten-day periods of each orbit around the Sun, which last roughly half a year. These 3 periods will correspond to perihelion and maximal solar latitude north and south. The Extreme Ultraviolet Imager is itself a suite of three UV and EUV telescopes that observe the solar atmosphere both globally as well as at very high resolution. The two high-resolution imagers (HRIs) will image the solar atmosphere in the chromospheric Lyman alpha line and the coronal 17nm pass band with a resolution of 0.5 arcsec. From perihelion, this will correspond to a pixel footprint on the solar disc of (110km)^2 . The Full Sun Imager (FSI), working at the 17.4 nm and 30.4 nm EUV passbands, will provide a global view of the solar atmosphere and is therefore an essential building block for the "connection science" of the Solar Orbiter mission. The FSI field of view is large enough (228arcmin) that, even at perihelion and at maximal off-points by Solar Orbiter, the full solar disk remains in the field of view. This large FOV and the FSI's high sensitivity will allow to image the "transition corona" where the topology of streamers and pseudo-streamers fades in the solar wind. Furthermore, FSI will be the first to image all this from out of the ecliptic. In this talk we will give an overview of the EUI instrument. We will focus on the novel aspects of EUI that will allow it to image beyond what previous EUV imagers could show us: EUV imaging from the highest solar latitude, with the widest field-of-view and at highest spatial resolution. Title: Evolution of flux rope, CME and associated EUV wave in the 10-Sep-2018 X8.2 event Authors: Podladchikova, Tatiana; Veronig, Astrid M.; Dissauer, Karin; Temmer, Manuela; Seaton, Daniel B.; Long, David; Guo, Jingnan; Vršnak, Bojan; Harra, Louise; Kliem, Bernhard Bibcode: 2018csc..confE..38P Altcode: We combine the high-cadence and large field-of-view EUV imagery of the Atmospheric Imaging Assembly (AIA) onboard SDO and the Solar Ultraviolet Imager (SUVI) onboard GOES-16 to study the origin and impulsive evolution of the fast CME that originated in the September 10th 2017 X8.2 event as well as the initiation of the associated EUV wave. In the LASCO field-of-view, the CME reveals speeds >3000 km/s. In the low-to-mid corona, it shows a distinct bubble in the EUV imagery that reveals a significant lateral overexpansion. In addition, is also shows a distinct expanding cavity that is interpreted as manifestation of the flux rope driving the eruption. We present a method to automatically identify and segment the CME bubble in SUVI images and to derive its radial and lateral evolution up to about 2 solar radii, in terms of velocity and acceleration. These measurements are set into context with the evolution of the embedded flux rope/cavity observed by AIA. The observations show clear signatures of new poloidal flux added to the flux rope by magnetic reconnection in the current sheet beneath the eruptive structure, which is important for the high accelerations observed in this event. The radial propagation of the CME shell revealed a peak value of the acceleration of about 5.3 km/s2, whereas the lateral expansion reached a peak value of 10.1 km/s2, which is the largest value reported so far. The flux rope/cavity reveals a radial acceleration of 6.7 km/s2 and lateral acceleration of 5.3 km/s2. We note that at this early evolution phase, the speed of the cavity/flux rope is higher than that of the CME bubble (front). The EUV wave associated with this eruption was observed by AIA, SUVI and STEREO-A EUVI, which had a separation angle with Earth of 128°, and the common field of view of the spacecraft was 52°. AIA and SUVI images above the solar limb reveal the initiation of the EUV wave by the accelerating flanks of the CME bubble, followed by detachment and propagation of the wave with a speed of 1100 km/s. The EUV wave shows a global propagation over the full hemisphere visible to Earth view as well as into the STEREO-A field-of-view. We study the propagation and kinematics of the direct as well as the various reflected and refracted EUV wave components on the solar sphere, finding speeds in the range from 370 to 1010 km/s. Finally, we note that this EUV wave is also distinct as it reveals propagation and transmission through the polar coronal holes. Title: Coronal and chromospheric observations of pre- and post-flare plasma evolution Authors: Long, David; Reid, Aaron; Harra, Louise; Mathioudakis, Mihalis Bibcode: 2018csc..confE..16L Altcode: Solar flares are among the most energetic and spectacular events occurring in our solar system, produced by the release of stored magnetic energy in the solar atmosphere through the reconnection of twisted magnetic fields. Although the magnetic field itself is difficult to observe in the solar atmosphere, we can gain vital insights into the reconnection process by studying the evolution of solar plasma prior to and following the flare. Here we present contemporaneous spectroscopic and imaging observations of an X9.3 solar flare from 2017-September-6. This was the largest flare of the current solar cycle to date, and was well observed in the corona by SDO/AIA and Hinode/EIS as well as in the chromosphere by instruments at the ground-based Swedish Solar Telescope. This combination of observations provides spectroscopic information throughout the solar atmosphere, giving a unique insight into the evolution of plasma in the lead-up to and following the flare. Title: Probing the evolution of a coronal cavity within a solar coronal mass ejection. Authors: Harra, Louise K.; Doschek, G. A.; Hara, Hirohisa; Long, David; Warren, Harry; Matthews, Sarah; Lee, Kyoung-Sun; Jenkins, Jack Bibcode: 2018cosp...42E1381H Altcode: On the 10 September 2017, an X-class solar flare erupted at the solar limb. The associated coronal mass ejection (CME) had the classic three part structure with a bright core surrounded by a dark cavity. This event was captured perfectly by the Hinode EUV imaging spectrometer (EIS). The EIS instrument captured spectroscopically the flaring loops, the current sheet and the cavity for the first time. In the 'standard flare model', magnetic reconnection of coronal loops occurs following the eruption of a magnetic flux rope. The flux rope is a key element of the flare process and eruption but is inherently difficult to observe. Dark cavities observed within a CME are assumed to be flux ropes. The observations we describe here, provide an insight into the characteristics of a cavity, and how the rapid injection of energy from the flare underneath forces the rapid expansion of the flux rope resulting in the eruption. Doppler shifts of over 200 km/s are measured at either end of the cavity. There is mixed temperature plasma - cool material in the centre that also has strong flows, and hot FeXXIV emission being observed. SDO Atmospheric Imaging Assembly (AIA) data shows that the cavity erupts rapidly, and is being driven by the non-thermal energy input from the flare below as measured from Fermi data. Title: The EUI flight instrument of Solar Orbiter: from optical alignment to end-to-end calibration Authors: Halain, J. -P.; Renotte, E.; Auchère, F.; Berghmans, D.; Delmotte, F.; Harra, L.; Schmutz, W.; Schühle, U.; Aznar Cuadrado, R.; Dumesnil, C.; Gyo, M.; Kennedy, T.; Verbeeck, C.; Barbay, J.; Giordanengo, B.; Gissot, S.; Gottwald, A.; Heerlein, K.; Hellin, M. -L.; Hermans, A.; Hervier, V.; Jacques, L.; Laubis, C.; Mazzoli, A.; Meining, S.; Mercier, R.; Philippon, A.; Roose, S.; Rossi, L.; Scholze, F.; Smith, P.; Teriaca, L.; Zhang, X.; Rochus, P. Bibcode: 2018SPIE10699E..0HH Altcode: The Extreme Ultraviolet Imager (EUI) instrument for the Solar Orbiter mission will image the solar corona in the extreme ultraviolet (17.1 nm and 30.4 nm) and in the vacuum ultraviolet (121.6 nm) spectral ranges. The development of the EUI instrument has been successfully completed with the optical alignment of its three channels' telescope, the thermal and mechanical environmental verification, the electrical and software validations, and an end-toend on-ground calibration of the two-units' flight instrument at the operating wavelengths. The instrument has been delivered and installed on the Solar Orbiter spacecraft, which is now undergoing all preparatory activities before launch. Title: The Triggering of the 2014 March 29 Filament Eruption Authors: Woods, Magnus M.; Inoue, Satoshi; Harra, Louise K.; Matthews, Sarah A.; Kusano, Kanya; Kalmoni, Nadine M. E. Bibcode: 2018ApJ...860..163W Altcode: 2018arXiv180505976W The X1 flare and associated filament eruption occurring in NOAA Active Region 12017 on SOL2014-03-29 has been a source of intense study. In this work, we analyze the results of a series of nonlinear force-free field extrapolations of the flare’s pre- and post-flare periods. In combination with observational data provided by the IRIS, Hinode, and Solar Dynamics Observatory missions, we have confirmed the existence of two flux ropes present within the active region prior to flaring. Of these two flux ropes, we find that intriguingly only one erupts during the X1 flare. We propose that the reason for this is due to tether cutting reconnection allowing one of the flux ropes to rise to a torus unstable region prior to flaring, thus allowing it to erupt during the subsequent flare. Title: Mapping the Solar Wind to Its Source to Compare Coronal and Heliospheric Boundaries Authors: Macneil, Allan; Owen, Christopher; Wicks, Robert; Harra, Louise; Long, David Bibcode: 2018EGUGA..2015465M Altcode: We aim to understand the relationship between the observational properties of coronal holes, particularly their boundaries, and the composition of their associated solar wind. These are anomalous in that while the coronal boundaries appear sharp, the associated transition in solar wind ionisation and elemental abundance appears quite smooth. To do so we employ the standard two-step solar wind mapping technique; first assuming a constant and purely radial solar wind to map back to the source surface of a potential field source surface (PFSS) model, and then using field lines derived from this to select the likely source region at 1 solar radius. Such mapping techniques are of increasing importance as we approach the launch of Solar Orbiter, which aims to establish an unprecedented link between in situ and remote sensing observations. We find that despite its simplicity this technique maps compositionally cool (low charge-state) solar wind plasma back to the anticipated coronal hole source regions. Further, we test the agreement of features in the solar wind with both structure from EUV coronal images and the modelled magnetic field direction to test the quality of the backmapping and make adjustments to the technique. We directly compare heavy ion charge states observed in situ to coronal properties inferred from EUV data. We will present results and offer explanations for the evolution of solar wind charge state relative to the properties across source regions, in particular for the anomalous coronal hole boundaries. We will also analyse the viability of the chosen mapping technique for this study, and for others with Solar Orbiter. Title: Plasma Evolution within an Erupting Coronal Cavity Authors: Long, David M.; Harra, Louise K.; Matthews, Sarah A.; Warren, Harry P.; Lee, Kyoung-Sun; Doschek, George A.; Hara, Hirohisa; Jenkins, Jack M. Bibcode: 2018ApJ...855...74L Altcode: 2018arXiv180201391L Coronal cavities have previously been observed to be associated with long-lived quiescent filaments and are thought to correspond to the associated magnetic flux rope. Although the standard flare model predicts a coronal cavity corresponding to the erupting flux rope, these have only been observed using broadband imaging data, restricting an analysis to the plane-of-sky. We present a unique set of spectroscopic observations of an active region filament seen erupting at the solar limb in the extreme ultraviolet. The cavity erupted and expanded rapidly, with the change in rise phase contemporaneous with an increase in nonthermal electron energy flux of the associated flare. Hot and cool filamentary material was observed to rise with the erupting flux rope, disappearing suddenly as the cavity appeared. Although strongly blueshifted plasma continued to be observed flowing from the apex of the erupting flux rope, this outflow soon ceased. These results indicate that the sudden injection of energy from the flare beneath forced the rapid eruption and expansion of the flux rope, driving strong plasma flows, which resulted in the eruption of an under-dense filamentary flux rope. Title: Photospheric and Coronal Abundances in an X8.3 Class Limb Flare Authors: Doschek, G. A.; Warren, H. P.; Harra, L. K.; Culhane, J. L.; Watanabe, T.; Hara, H. Bibcode: 2018ApJ...853..178D Altcode: We analyze solar elemental abundances in coronal post-flare loops of an X8.3 flare (SOL2017-09-10T16:06) observed on the west limb on 2017 September 10 near 18 UT using spectra recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The abundances in the corona can differ from photospheric abundances due to the first ionization potential (FIP) effect. In some loops of this flare, we find that the abundances appear to be coronal at the loop apices or cusps, but steadily transform from coronal to photospheric as the loop footpoint is approached. This result is found from the intensity ratio of a low-FIP ion spectral line (Ca XIV) to a high-FIP ion spectral line (Ar XIV) formed at about the same temperature (4-5 MK). Both lines are observed close in wavelength. Temperature, which could alter the interpretation, does not appear to be a factor based on intensity ratios of Ca XV lines to a Ca XIV line. We discuss the abundance result in terms of the Laming model of the FIP effect, which is explained by the action of the ponderomotive force in magnetohydrodynamic (MHD) waves in coronal loops and in the underlying chromosphere. Title: The First Decade of Hinode: Understanding Coronal Mass Ejections Authors: Harra, Louise Bibcode: 2018ASSL..449..149H Altcode: No abstract at ADS Title: Non-thermal distributions and energy transport in the solar flares Authors: Matthews, Sarah; del Zanna, Guilio; Calcines, Ariadna; Mason, Helen; Mathioudakis, Mihalis; Culhane, Len; Harra, Louise; van Driel-Gesztelyi, Lidia; Green, Lucie; Long, David; Baker, Deb; Valori, Gherardo Bibcode: 2017arXiv171200773M Altcode: Determining the energy transport mechanisms in flares remains a central goal in solar flares physics that is still not adequately answered by the 'standard flare model'. In particular, the relative roles of particles and/or waves as transport mechanisms, the contributions of low energy protons and ions to the overall flare budget, and the limits of low energy non-thermal electron distribution are questions that still cannot be adequately reconciled with current instrumentation. In this 'White Paper' submitted in response to the call for inputs to the Next Generation Solar Physics Mission review process initiated by JAXA, NASA and ESA in 2016, we outline the open questions in this area and possible instrumentation that could provide the required observations to help answer these and other flare-related questions. Title: Fine Structure and Dynamics of the Solar Atmosphere Authors: Vargas Domínguez, S.; Kosovichev, A. G.; Antolin, P.; Harra, L. Bibcode: 2017IAUS..327.....V Altcode: No abstract at ADS Title: Magnetic Properties of Solar Active Regions that Govern Large Solar Flares and Eruptions Authors: Toriumi, Shin; Schrijver, Carolus J.; Harra, Louise; Hudson, Hugh S.; Nagashima, Kaori Bibcode: 2017SPD....4820001T Altcode: Strong flares and CMEs are often produced from active regions (ARs). In order to better understand the magnetic properties and evolutions of such ARs, we conducted statistical investigations on the SDO/HMI and AIA data of all flare events with GOES levels >M5.0 within 45 deg from the disk center for 6 years from May 2010 (from the beginning to the declining phase of solar cycle 24). Out of the total of 51 flares from 29 ARs, more than 80% have delta-sunspots and about 15% violate Hale’s polarity rule. We obtained several key findings including (1) the flare duration is linearly proportional to the separation of the flare ribbons (i.e., scale of reconnecting magnetic fields) and (2) CME-eruptive events have smaller sunspot areas. Depending on the magnetic properties, flaring ARs can be categorized into several groups, such as spot-spot, in which a highly-sheared polarity inversion line is formed between two large sunspots, and spot-satellite, where a newly-emerging flux next to a mature sunspot triggers a compact flare event. These results point to the possibility that magnetic structures of the ARs determine the characteristics of flares and CMEs. In the presentation, we will also show new results from the systematic flux emergence simulations of delta-sunspot formation and discuss the evolution processes of flaring ARs. Title: Measuring Velocities in the Early Stage of an Eruption: Using “Overlappogram” Data from Hinode EIS Authors: Harra, Louise K.; Hara, Hirohisa; Doschek, George A.; Matthews, Sarah; Warren, Harry; Culhane, J. Leonard; Woods, Magnus M. Bibcode: 2017ApJ...842...58H Altcode: In order to understand the onset phase of a solar eruption, plasma parameter measurements in the early phases are key to constraining models. There are two current instrument types that allow us to make such measurements: narrow-band imagers and spectrometers. In the former case, even narrow-band filters contain multiple emission lines, creating some temperature confusion. With imagers, however, rapid cadences are achievable and the field of view can be large. Velocities of the erupting structures can be measured by feature tracking. In the spectrometer case, slit spectrometers can provide spectrally pure images by “rastering” the slit to build up an image. This method provides limited temporal resolution, but the plasma parameters can be accurately measured, including velocities along the line of sight. Both methods have benefits and are often used in tandem. In this paper we demonstrate for the first time that data from the wide slot on the Hinode EUV Imaging Spectrometer, along with imaging data from AIA, can be used to deconvolve velocity information at the start of an eruption, providing line-of-sight velocities across an extended field of view. Using He II 256 Å slot data at flare onset, we observe broadening or shift(s) of the emission line of up to ±280 km s-1. These are seen at different locations—the redshifted plasma is seen where the hard X-ray source is later seen (energy deposition site). In addition, blueshifted plasma shows the very early onset of the fast rise of the filament. Title: A study of the long term evolution in active region upflows Authors: Harra, Louise K.; Ugarte-Urra, Ignacio; De Rosa, Marc; Mandrini, Cristina; van Driel-Gesztelyi, Lidia; Baker, Deborah; Culhane, J. Leonard; Démoulin, Pascal Bibcode: 2017PASJ...69...47H Altcode: Since their discovery, upflows at the edges of active regions have attracted a lot of interest, primarily as they could potentially contribute to the slow solar wind. One aspect that has not been studied yet is how the long term evolution of active regions impacts the upflows. In this work, we analyze one active region that survives three solar rotations. We track how the flows change with time. We use local and global modeling of the decaying active region to determine how the age of the active region will impact the extent of the open magnetic fields, and then how some of the upflows could become outflows. We finish with a discussion of how these results, set in a broader context, can be further developed with the Solar Orbiter mission. Title: Turbulent Kinetic Energy in the Energy Balance of a Solar Flare Authors: Kontar, E. P.; Perez, J. E.; Harra, L. K.; Kuznetsov, A. A.; Emslie, A. G.; Jeffrey, N. L. S.; Bian, N. H.; Dennis, B. R. Bibcode: 2017PhRvL.118o5101K Altcode: 2017arXiv170302392K The energy released in solar flares derives from a reconfiguration of magnetic fields to a lower energy state, and is manifested in several forms, including bulk kinetic energy of the coronal mass ejection, acceleration of electrons and ions, and enhanced thermal energy that is ultimately radiated away across the electromagnetic spectrum from optical to x rays. Using an unprecedented set of coordinated observations, from a suite of instruments, we here report on a hitherto largely overlooked energy component—the kinetic energy associated with small-scale turbulent mass motions. We show that the spatial location of, and timing of the peak in, turbulent kinetic energy together provide persuasive evidence that turbulent energy may play a key role in the transfer of energy in solar flares. Although the kinetic energy of turbulent motions accounts, at any given time, for only ∼(0.5 - 1 )% of the energy released, its relatively rapid (∼1 - 10 s ) energization and dissipation causes the associated throughput of energy (i.e., power) to rival that of major components of the released energy in solar flares, and thus presumably in other astrophysical acceleration sites. Title: Observations and Modelling of the Pre-flare Period of the 29 March 2014 X1 Flare Authors: Woods, M. M.; Harra, L. K.; Matthews, S. A.; Mackay, D. H.; Dacie, S.; Long, D. M. Bibcode: 2017SoPh..292...38W Altcode: 2017arXiv170106457W On 29 March 2014, NOAA Active Region (AR) 12017 produced an X1 flare that was simultaneously observed by an unprecedented number of observatories. We have investigated the pre-flare period of this flare from 14:00 UT until 19:00 UT using joint observations made by the Interface Region Imaging Spectrometer (IRIS) and the Hinode Extreme Ultraviolet Imaging Spectrometer (EIS). Spectral lines providing coverage of the solar atmosphere from the chromosphere to the corona were analysed to investigate pre-flare activity within the AR. The results of the investigation have revealed evidence of strongly blue-shifted plasma flows, with velocities up to 200 kms−1, being observed 40 minutes prior to flaring. These flows are located along the filament present in the active region and are both spatially discrete and transient. In order to constrain the possible explanations for this activity, we undertake non-potential magnetic field modelling of the active region. This modelling indicates the existence of a weakly twisted flux rope along the polarity inversion line in the region where a filament and the strong pre-flare flows are observed. We then discuss how these observations relate to the current models of flare triggering. We conclude that the most likely drivers of the observed activity are internal reconnection in the flux rope, early onset of the flare reconnection, or tether-cutting reconnection along the filament. Title: Magnetic Properties of Solar Active Regions That Govern Large Solar Flares and Eruptions Authors: Toriumi, Shin; Schrijver, Carolus J.; Harra, Louise K.; Hudson, Hugh; Nagashima, Kaori Bibcode: 2017ApJ...834...56T Altcode: 2016arXiv161105047T Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim of understanding the magnetic properties that govern such flares and eruptions, we systematically survey all flare events with Geostationary Orbiting Environmental Satellite levels of ≥M5.0 within 45° from disk center between 2010 May and 2016 April. These criteria lead to a total of 51 flares from 29 ARs, for which we analyze the observational data obtained by the Solar Dynamics Observatory. More than 80% of the 29 ARs are found to exhibit δ-sunspots, and at least three ARs violate Hale’s polarity rule. The flare durations are approximately proportional to the distance between the two flare ribbons, to the total magnetic flux inside the ribbons, and to the ribbon area. From our study, one of the parameters that clearly determine whether a given flare event is CME-eruptive or not is the ribbon area normalized by the sunspot area, which may indicate that the structural relationship between the flaring region and the entire AR controls CME productivity. AR characterization shows that even X-class events do not require δ-sunspots or strong-field, high-gradient polarity inversion lines. An investigation of historical observational data suggests the possibility that the largest solar ARs, with magnetic flux of 2 × 1023 Mx, might be able to produce “superflares” with energies of the order of 1034 erg. The proportionality between the flare durations and magnetic energies is consistent with stellar flare observations, suggesting a common physical background for solar and stellar flares. Title: Fundamental Physics of the Slow Solar Wind - What do we Know? Authors: Ofman, L.; Abbo, L.; Antiochos, S. K.; Hansteen, V. H.; Harra, L.; Ko, Y. K.; Lapenta, G.; Li, B.; Riley, P.; Strachan, L.; von Steiger, R.; Wang, Y. M. Bibcode: 2016AGUFMSH42A..01O Altcode: Fundamental physical properties of the slow solar wind (SSW), such as density, temperature, outflow speed, heavy ion abundances and charges states were obtained from in-situ measurements at 1AU in the past from WIND, ACE, and other spacecraft. Plasma and magnetic field measurement are available as close as 0.3 AU from Helios data, Spektr-R, and MESSENGER spacecraft. Remote sensing spectroscopic measurements are available in the corona and below from SOHO/UVCS, Hinode, and other missions. One of the major objectives of the Solar Orbiter and Solar Probe Plus missions is to study the sources of the SSW close to the Sun. The present state of understanding of the physics of the SSW is based on the combination of the existing observations, theoretical and numerical 3D MHD and multi-fluid models, that connect between the SSW sources in the corona and the heliosphere. Recently, hybrid models that combine fluid electrons and kinetic ions of the expanding solar wind were developed, and provide further insights of the local SSW plasma heating processes that related to turbulent magnetic fluctuations spectra and kinetic ion instabilities observed in the SSW plasma. These models produce the velocity distribution functions (VDFs) of the protons and heavier ions as well as the ion anisotropic temperatures. I will discuss the results of the above observations and models, and review the current status of our understanding of the fundamental physics of the SSW. I will review the open questions, and discuss how they could be addressed with near future observations and models. Title: Slow Solar Wind: Observations and Modeling Authors: Abbo, L.; Ofman, L.; Antiochos, S. K.; Hansteen, V. H.; Harra, L.; Ko, Y. -K.; Lapenta, G.; Li, B.; Riley, P.; Strachan, L.; von Steiger, R.; Wang, Y. -M. Bibcode: 2016SSRv..201...55A Altcode: 2016SSRv..tmp...34A While it is certain that the fast solar wind originates from coronal holes, where and how the slow solar wind (SSW) is formed remains an outstanding question in solar physics even in the post-SOHO era. The quest for the SSW origin forms a major objective for the planned future missions such as the Solar Orbiter and Solar Probe Plus. Nonetheless, results from spacecraft data, combined with theoretical modeling, have helped to investigate many aspects of the SSW. Fundamental physical properties of the coronal plasma have been derived from spectroscopic and imaging remote-sensing data and in situ data, and these results have provided crucial insights for a deeper understanding of the origin and acceleration of the SSW. Advanced models of the SSW in coronal streamers and other structures have been developed using 3D MHD and multi-fluid equations. Title: Properties and Developments of Flaring Active Regions Authors: Toriumi, Shin; Schrijver, Carolus J.; Harra, Louise K.; Hudson, Hugh; Nagashima, Kaori Bibcode: 2016usc..confE..15T Altcode: Larger flares and CMEs are often produced from active regions (ARs). In order to better understand the magnetic properties and evolutions of such ARs, we picked up all flare events with GOES levels >M5.0 with heliocentric angles of <45 deg in the period of May 2010 to April 2016, which led to a total of 29 ARs with 51 flares. We analyzed the observational data obtained by SDO and found that more than 80% of the 29 ARs have delta-sunspots. Most of them can be classified depending on their magnetic structures into (1) spot-spot, where a long sheared polarity inversion line (PIL: characterized by flare ribbons) is formed between two major sunspots, and (2) spot-satellite, where a newly-emerging minor bipole next to a pre-existing spot creates a compact PIL. The remaining minor groups are (3) quadrupole, where two emerging bipoles produce a PIL in between, and (4) inter-AR, which produces flares not from delta-spots but from between two separated ARs. From statistical investigations we found for example that the spot-spot group generally shows long-duration events due to large coronal structures, while the spot-satellite has impulsive events because of their compact magnetic nature. We will also present flux emergence simulations and discuss their formation processes. Title: The Characteristics of Solar X-Class Flares and CMEs: A Paradigm for Stellar Superflares and Eruptions? Authors: Harra, Louise K.; Schrijver, Carolus J.; Janvier, Miho; Toriumi, Shin; Hudson, Hugh; Matthews, Sarah; Woods, Magnus M.; Hara, Hirohisa; Guedel, Manuel; Kowalski, Adam; Osten, Rachel; Kusano, Kanya; Lueftinger, Theresa Bibcode: 2016SoPh..291.1761H Altcode: 2016SoPh..tmp..111H This paper explores the characteristics of 42 solar X-class flares that were observed between February 2011 and November 2014, with data from the Solar Dynamics Observatory (SDO) and other sources. This flare list includes nine X-class flares that had no associated CMEs. In particular our aim was to determine whether a clear signature could be identified to differentiate powerful flares that have coronal mass ejections (CMEs) from those that do not. Part of the motivation for this study is the characterization of the solar paradigm for flare/CME occurrence as a possible guide to the stellar observations; hence we emphasize spectroscopic signatures. To do this we ask the following questions: Do all eruptive flares have long durations? Do CME-related flares stand out in terms of active-region size vs. flare duration? Do flare magnitudes correlate with sunspot areas, and, if so, are eruptive events distinguished? Is the occurrence of CMEs related to the fraction of the active-region area involved? Do X-class flares with no eruptions have weaker non-thermal signatures? Is the temperature dependence of evaporation different in eruptive and non-eruptive flares? Is EUV dimming only seen in eruptive flares? We find only one feature consistently associated with CME-related flares specifically: coronal dimming in lines characteristic of the quiet-Sun corona, i.e. 1 - 2 MK. We do not find a correlation between flare magnitude and sunspot areas. Although challenging, it will be of importance to model dimming for stellar cases and make suitable future plans for observations in the appropriate wavelength range in order to identify stellar CMEs consistently. Title: The qualification campaign of the EUI instrument of Solar Orbiter Authors: Halain, J. -P.; Rochus, P.; Renotte, E.; Hermans, A.; Jacques, L.; Mazzoli, A.; Auchère, F.; Berghmans, D.; Harra, L.; Schühle, U.; Schmutz, W.; Aznar Cuadrado, R.; Dumesnil, C.; Gyo, M.; Kennedy, T.; Verbeeck, C.; Smith, P. Bibcode: 2016SPIE.9905E..2XH Altcode: The Extreme Ultraviolet Imager (EUI) instrument is one of the ten scientific instruments on board the Solar Orbiter mission to be launched in October 2018. It will provide full-sun and high-resolution images of the solar corona in the extreme ultraviolet (17.1 nm and 30.4 nm) and in the vacuum ultraviolet (121.6 nm). The validation of the EUI instrument design has been completed with the Assembly, Integration and Test (AIT) of the instrument two-units Qualification Model (QM). Optical, electrical, electro-magnetic compatibility, thermal and mechanical environmental verifications were conducted and are summarized here. The integration and test procedures for the Flight Model (FM) instrument and sub-systems were also verified. Following the Qualification Review, the flight instrument activities were started with the assembly of the flight units. The mechanical and thermal acceptance tests and an end-to-end final calibration in the (E)UV will then be conducted before delivery for integration on the Solar Orbiter Spacecraft by end of 2016. Title: An Investigation of the Sources of Earth-directed Solar Wind during Carrington Rotation 2053 Authors: Fazakerley, A. N.; Harra, L. K.; van Driel-Gesztelyi, L. Bibcode: 2016ApJ...823..145F Altcode: In this work we analyze multiple sources of solar wind through a full Carrington Rotation (CR 2053) by analyzing the solar data through spectroscopic observations of the plasma upflow regions and the in situ data of the wind itself. Following earlier authors, we link solar and in situ observations by a combination of ballistic backmapping and potential-field source-surface modeling. We find three sources of fast solar wind that are low-latitude coronal holes. The coronal holes do not produce a steady fast wind, but rather a wind with rapid fluctuations. The coronal spectroscopic data from Hinode’s Extreme Ultraviolet Imaging Spectrometer show a mixture of upflow and downflow regions highlighting the complexity of the coronal hole, with the upflows being dominant. There is a mix of open and multi-scale closed magnetic fields in this region whose (interchange) reconnections are consistent with the up- and downflows they generate being viewed through an optically thin corona, and with the strahl directions and freeze-in temperatures found in in situ data. At the boundary of slow and fast wind streams there are three short periods of enhanced-velocity solar wind, which we term intermediate based on their in situ characteristics. These are related to active regions that are located beside coronal holes. The active regions have different magnetic configurations, from bipolar through tripolar to quadrupolar, and we discuss the mechanisms to produce this intermediate wind, and the important role that the open field of coronal holes adjacent to closed-field active regions plays in the process. Title: A Comparison of Global Magnetic Field Skeletons and Active-Region Upflows Authors: Edwards, S. J.; Parnell, C. E.; Harra, L. K.; Culhane, J. L.; Brooks, D. H. Bibcode: 2016SoPh..291..117E Altcode: 2015SoPh..tmp..161E Plasma upflows have been detected in active regions using Doppler velocity maps. The origin and nature of these upflows is not well known with many of their characteristics determined from the examination of single events. In particular, some studies suggest these upflows occur along open field lines and, hence, are linked to sources of the solar wind. To investigate the relationship these upflows may have with the solar wind, and to probe what may be driving them, this paper considers seven active regions observed on the solar disc using the Extreme ultraviolet Imaging Spectrometer aboard Hinode between August 2011 and September 2012. Plasma upflows are observed in all these active regions. The locations of these upflows are compared to the global potential magnetic field extrapolated from the Solar Dynamics Observatory, Helioseismic and Magnetic Imager daily synoptic magnetogram taken on the day the upflows were observed. The structure of the magnetic field is determined by constructing its magnetic skeleton in order to help identify open-field regions and also sites where magnetic reconnection at global features is likely to occur. As a further comparison, measurements of the temperature, density and composition of the plasma are taken from regions with active-region upflows. In most cases the locations of the upflows in the active regions do not correspond to areas of open field, as predicted by a global coronal potential-field model, and therefore these upflows are not always sources of the slow solar wind. The locations of the upflows are, in general, intersected by separatrix surfaces associated with null points located high in the corona; these could be important sites of reconnection with global consequences. Title: Slow Solar Wind: Observable Characteristics for Constraining Modelling Authors: Ofman, L.; Abbo, L.; Antiochos, S. K.; Hansteen, V. H.; Harra, L.; Ko, Y. K.; Lapenta, G.; Li, B.; Riley, P.; Strachan, L.; von Steiger, R.; Wang, Y. M. Bibcode: 2015AGUFMSH11F..03O Altcode: The Slow Solar Wind (SSW) origin is an open issue in the post SOHO era and forms a major objective for planned future missions such as the Solar Orbiter and Solar Probe Plus.Results from spacecraft data, combined with theoretical modeling, have helped to investigate many aspects of the SSW. Fundamental physical properties of the coronal plasma have been derived from spectroscopic and imaging remote-sensing data and in-situ data, and these results have provided crucial insights for a deeper understanding of the origin and acceleration of the SSW.Advances models of the SSW in coronal streamers and other structures have been developed using 3D MHD and multi-fluid equations.Nevertheless, there are still debated questions such as:What are the source regions of SSW? What are their contributions to the SSW?Which is the role of the magnetic topology in corona for the origin, acceleration and energy deposition of SSW?Which are the possible acceleration and heating mechanisms for the SSW?The aim of this study is to present the insights on the SSW origin and formationarisen during the discussions at the International Space Science Institute (ISSI) by the Team entitled ''Slowsolar wind sources and acceleration mechanisms in the corona'' held in Bern (Switzerland) in March2014--2015. The attached figure will be presented to summarize the different hypotheses of the SSW formation. Title: Preface: Probing the Sun Inside and Out Authors: Harra, Louise; Baker, Deborah; Howe, Rachel; Leibacher, John; van Driel-Gesztelyi, Lidia Bibcode: 2015SoPh..290.3091H Altcode: 2015SoPh..tmp..167H No abstract at ADS Title: Persistent Near-Surface Flow Structures from Local Helioseismology Authors: Howe, Rachel; Komm, R. W.; Baker, D.; Harra, L.; van Driel-Gesztelyi, L.; Bogart, R. S. Bibcode: 2015SoPh..290.3137H Altcode: 2015arXiv150706525H; 2015SoPh..tmp..115H Near-surface flows measured by the ring-diagram technique of local helioseismology show structures that persist over multiple rotations. We examine these phenomena using data from the Global Oscillation Network Group (GONG) and the Helioseismic and Magnetic Imager (HMI) and show that a correlation analysis of the structures can be used to estimate the rotation rate as a function of latitude, giving a result consistent with the near-surface rate from global helioseismology and slightly slower than that obtained from a similar analysis of the surface magnetic field strength. At latitudes of 60∘ and above, the HMI flow data reveal a strong signature of a two-sided zonal flow structure. This signature may be related to recent reports of "giant cells" in solar convection. Title: A Study of the Coronal Non-thermal Velocity in Polar Regions During the Rise from Solar Minimum to Solar Maximum in Cycle 24 Authors: Harra, L.; Baker, D.; Edwards, S. J.; Hara, H.; Howe, R.; van Driel-Gesztelyi, L. Bibcode: 2015SoPh..290.3203H Altcode: 2015SoPh..tmp....8H We explore the changes in coronal non-thermal velocity (Vnt) measurements at the poles from solar minimum to solar maximum using Hinode EUV Imaging Spectrometer data. We find that although the intensity in the corona at the poles does tend to increase with the cycle, there are no significant changes in the Vnt values. The locations of enhanced Vnt values measured do not always have a counterpart in intensity, and they are sometimes located in weak emission regions. Unipolar magnetic streams, created through diffusion of the following polarity of the decaying active regions, slowly progress towards the poles. These streams are expected to be related to magnetic nulls as locations that indicate an increased likelihood for magnetic reconnection to occur. Through global potential field source-surface modelling, we determine how the number of nulls varied during the cycle and find that those that lie at < 1.1 solar radii vary significantly. We search for a correlation between the variation of the magnetic nulls and the Vnt values, as it may be expected that with an increasing number of nulls, the Vnt values in the corona increase as well. There is no correlation with the Vnt values, however. This indicates that the magnetic structures that create the enhanced Vnt behaviour are small-scale features and hence not easily measurable at the poles. Because they do not change during the solar cycle, they are likely to be created by a local dynamo. The variation of the upper range of Vnt is reduced, which highlights that strongly dynamic behaviour is reduced as the solar maximum approaches. This is likely to be due to the reduced area of the polar coronal hole, which allows fewer opportunities for reconnection to occur between open and closed magnetic fields. Title: Spectroscopic Signatures Related to a Sunquake Authors: Matthews, S. A.; Harra, L. K.; Zharkov, S.; Green, L. M. Bibcode: 2015ApJ...812...35M Altcode: 2015arXiv150807216M The presence of flare-related acoustic emission (sunquakes (SQs)) in some flares, and only in specific locations within the flaring environment, represents a severe challenge to our current understanding of flare energy transport processes. In an attempt to contribute to understanding the origins of SQs we present a comparison of new spectral observations from Hinode’s EUV imaging Spectrometer (EIS) and the Interface Region Imaging Spectrograph (IRIS) of the chromosphere, transition region, and corona above an SQ, and compare them to the spectra observed in a part of the flaring region with no acoustic signature. Evidence for the SQ is determined using both time-distance and acoustic holography methods, and we find that unlike many previous SQ detections, the signal is rather dispersed, but that the time-distance and 6 and 7 mHz sources converge at the same spatial location. We also see some evidence for different evolution at different frequencies, with an earlier peak at 7 mHz than at 6 mHz. Using EIS and IRIS spectroscopic measurements we find that in this location, at the time of the 7 mHz peak the spectral emission is significantly more intense, shows larger velocity shifts and substantially broader profiles than in the location with no SQ, and there is a good correlation between blueshifted, hot coronal, hard X-ray (HXR), and redshifted chromospheric emission, consistent with the idea of a strong downward motion driven by rapid heating by nonthermal electrons and the formation of chromospheric shocks. Exploiting the diagnostic potential of the Mg ii triplet lines, we also find evidence for a single large temperature increase deep in the atmosphere, which is consistent with this scenario. The time of the 6 mHz and time-distance peak signal coincides with a secondary peak in the energy release process, but in this case we find no evidence of HXR emission in the quake location, instead finding very broad spectral lines, strongly shifted to the red, indicating the possible presence of a significant flux of downward propagating Alfvén waves. Title: The extreme UV imager telescope on-board the Solar Orbiter mission: overview of phase C and D Authors: Halain, J. -P.; Rochus, P.; Renotte, E.; Hermans, A.; Jacques, L.; Auchère, F.; Berghmans, D.; Harra, L.; Schühle, U.; Schmutz, W.; Zhukov, A.; Aznar Cuadrado, R.; Delmotte, F.; Dumesnil, C.; Gyo, M.; Kennedy, T.; Smith, P.; Tandy, J.; Mercier, R.; Verbeeck, C. Bibcode: 2015SPIE.9604E..0GH Altcode: The Solar Orbiter mission is composed of ten scientific instruments dedicated to the observation of the Sun's atmosphere and its heliosphere, taking advantage of an out-of ecliptic orbit and at perihelion reaching a proximity close to 0.28 A.U. On board Solar Orbiter, the Extreme Ultraviolet Imager (EUI) will provide full-Sun image sequences of the solar corona in the extreme ultraviolet (17.1 nm and 30.4 nm), and high-resolution image sequences of the solar disk in the extreme ultraviolet (17.1 nm) and in the vacuum ultraviolet (121.6 nm). The EUI concept uses heritage from previous similar extreme ultraviolet instrument. Additional constraints from the specific orbit (thermal and radiation environment, limited telemetry download) however required dedicated technologies to achieve the scientific objectives of the mission. The development phase C of the instrument and its sub-systems has been successfully completed, including thermomechanical and electrical design validations with the Structural Thermal Model (STM) and the Engineering Model (EM). The instrument STM and EM units have been integrated on the respective spacecraft models and will undergo the system level tests. In parallel, the Phase D has been started with the sub-system qualifications and the flight parts manufacturing. The next steps of the EUI development will be the instrument Qualification Model (QM) integration and qualification tests. The Flight Model (FM) instrument activities will then follow with the acceptance tests and calibration campaigns. Title: Astronomical techniques in intensive care Authors: Harra, Louise K.; Pollard, Tom; Williams, David; Fong, Kevin Bibcode: 2015A&G....56c3.18H Altcode: Louise K Harra, Tom Pollard, Dave Williams and Kevin Fong describe a collaboration that uses methods developed for solar astrophysics to support critically ill patients. Title: Analysis of a coronal mass ejection and corotating interaction region as they travel from the Sun passing Venus, Earth, Mars, and Saturn Authors: Prise, A. J.; Harra, L. K.; Matthews, S. A.; Arridge, C. S.; Achilleos, N. Bibcode: 2015JGRA..120.1566P Altcode: During June 2010 a good alignment in the solar system between Venus, STEREO-B, Mars, and Saturn provided an excellent opportunity to study the propagation of a coronal mass ejection (CME) and closely occurring corotating interaction region (CIR) from the Sun to Saturn. The CME erupted from the Sun at 01:30 UT on 20 June 2010,with v≈ 600 km s-1, as observed by STEREO-B, Solar Dynamics Observatory, and SOHO/Large Angle and Spectrometric Coronagraph. It arrived at Venus over 2 days later, some 3.5 days after a CIR is also detected here. The CIR was also observed at STEREO-B and Mars, prior to the arrival of the CME. The CME is not directed earthward, but the CIR is detected here less than 2 days after its arrival at Mars. Around a month later, a strong compression of the Saturn magnetosphere is observed by Cassini, consistent with the scenario that the CME and CIR have merged into a single solar transient. The arrival times of both the CME and the CIR at different locations were predicted using the ENLIL solar wind model. The arrival time of the CME at Venus, STEREO-B, and Mars is predicted to within 20 h of its actual detection, but the predictions for the CIR showed greater differences from observations, all over 1.5 days early. More accurate predictions for the CIR were found by extrapolating the travel time between different locations using the arrival times and speeds detected by STEREO-B and ACE. We discuss the implications of these results for understanding the propagation of solar transients. Title: Atmospheric Response of an Active Region to New Small Flux Emergence Authors: Shelton, D.; Harra, L.; Green, L. Bibcode: 2015SoPh..290..753S Altcode: 2014arXiv1412.5623S; 2015SoPh..tmp....5S We investigate the atmospheric response to a small emerging flux region (EFR) that occurred in the positive polarity of Active Region 11236 on 23 - 24 June 2011. Data from the Solar Dynamics Observatory's Atmospheric Imaging Assembly (AIA), the Helioseismic and Magnetic Imager (HMI), and Hinode's EUV imaging spectrometer (EIS) are used to determine the atmospheric response to new flux emerging into a pre-existing active region. Brightenings are seen forming in the upper photosphere, chromosphere, and corona over the EFR location whilst flux cancellation is observed in the photosphere. The impact of the flux emergence is far reaching, with new large-scale coronal loops forming up to 43 Mm from the EFR and coronal upflow enhancements of approximately 10 km s−1 on the north side of the EFR. Jets are seen forming in the chromosphere and the corona over the emerging serpentine field. This is the first time that coronal jets have been seen over the serpentine field. Title: Extreme-ultraviolet Observations of Global Coronal Wave Rotation Authors: Attrill, G. D. R.; Long, D. M.; Green, L. M.; Harra, L. K.; van Driel-Gesztelyi, L. Bibcode: 2014ApJ...796...55A Altcode: We present evidence of global coronal wave rotation in EUV data from SOHO/EIT, STEREO/EUVI, and SDO/AIA. The sense of rotation is found to be consistent with the helicity of the source region (clockwise for positive helicity, anticlockwise for negative helicity), with the source regions hosting sigmoidal structures. We also study two coronal wave events observed by SDO/AIA where no clear rotation (or sigmoid) is observed. The selected events show supporting evidence that they all originate with flux rope eruptions. We make comparisons across this set of observations (both with and without clear sigmoidal structures). On examining the magnetic configuration of the source regions, we find that the nonrotation events possess a quadrupolar magnetic configuration. The coronal waves that do show a rotation originate from bipolar source regions. Title: Looking closer at the Sun Authors: Harra, Louise K. Bibcode: 2014Sci...346..305H Altcode: No abstract at ADS Title: The Impact of a Filament Eruption on Nearby High-lying Cool Loops Authors: Harra, L. K.; Matthews, S. A.; Long, D. M.; Doschek, G. A.; De Pontieu, B. Bibcode: 2014ApJ...792...93H Altcode: 2014arXiv1409.0377H The first spectroscopic observations of cool Mg II loops above the solar limb observed by NASA's Interface Region Imaging Spectrograph (IRIS) are presented. During the observation period, IRIS is pointed off-limb, allowing the observation of high-lying loops, which reach over 70 Mm in height. Low-lying cool loops were observed by the IRIS slit-jaw camera for the entire four-hour observing window. There is no evidence of a central reversal in the line profiles, and the Mg II h/k ratio is approximately two. The Mg II spectral lines show evidence of complex dynamics in the loops with Doppler velocities reaching ±40 km s-1. The complex motions seen indicate the presence of multiple threads in the loops and separate blobs. Toward the end of the observing period, a filament eruption occurs that forms the core of a coronal mass ejection. As the filament erupts, it impacts these high-lying loops, temporarily impeding these complex flows, most likely due to compression. This causes the plasma motions in the loops to become blueshifted and then redshifted. The plasma motions are seen before the loops themselves start to oscillate as they reach equilibrium following the impact. The ratio of the Mg h/k lines also increases following the impact of the filament. Title: The extreme UV imager of solar orbiter: from detailed design to flight model Authors: Halain, J. -P.; Rochus, P.; Renotte, E.; Auchère, F.; Berghmans, D.; Harra, L.; Schühle, U.; Schmutz, W.; Zhukov, A.; Aznar Cuadrado, R.; Delmotte, F.; Dumesnil, C.; Gyo, M.; Kennedy, T.; Mercier, R.; Verbeeck, F.; Thome, M.; Heerlein, K.; Hermans, A.; Jacques, L.; Mazzoli, A.; Meining, S.; Rossi, L.; Tandy, J.; Smith, P.; Winter, B. Bibcode: 2014SPIE.9144E..08H Altcode: The Extreme Ultraviolet Imager (EUI) on-board the Solar Orbiter mission will provide full-sun and high-resolution image sequences of the solar atmosphere at selected spectral emission lines in the extreme and vacuum ultraviolet. After the breadboarding and prototyping activities that focused on key technologies, the EUI project has completed the design phase and has started the final manufacturing of the instrument and its validation. The EUI instrument has successfully passed its Critical Design Review (CDR). The process validated the detailed design of the Optical Bench unit and of its sub-units (entrance baffles, doors, mirrors, camera, and filter wheel mechanisms), and of the Electronic Box unit. In the same timeframe, the Structural and Thermal Model (STM) test campaign of the two units have been achieved, and allowed to correlate the associated mathematical models. The lessons learned from STM and the detailed design served as input to release the manufacturing of the Qualification Model (QM) and of the Flight Model (FM). The QM will serve to qualify the instrument units and sub-units, in advance of the FM acceptance tests and final on-ground calibration. Title: An Investigation of the CME of 3 November 2011 and Its Associated Widespread Solar Energetic Particle Event Authors: Prise, A. J.; Harra, L. K.; Matthews, S. A.; Long, D. M.; Aylward, A. D. Bibcode: 2014SoPh..289.1731P Altcode: 2013arXiv1312.2965P Multi-spacecraft observations are used to study the in-situ effects of a large coronal mass ejection (CME) erupting from the farside of the Sun on 3 November 2011, with particular emphasis on the associated solar energetic particle (SEP) event. At that time both Solar Terrestrial Relations Observatory (STEREO) spacecraft were located more than 90 degrees from Earth and could observe the CME eruption directly, with the CME visible on-disk from STEREO-B and off the limb from STEREO-A. Signatures of pressure variations in the corona such as deflected streamers were seen, indicating the presence of a coronal shock associated with this CME eruption. The evolution of the CME and an associated extreme-ultraviolet (EUV) wave were studied using EUV and coronagraph images. It was found that the lateral expansion of the CME low in the corona closely tracked the propagation of the EUV wave, with measured velocities of 240±19 km s−1 and 221±15 km s−1 for the CME and wave, respectively. Solar energetic particles were observed to arrive first at STEREO-A, followed by electrons at the Wind spacecraft at L1, then STEREO-B, and finally protons arrived simultaneously at Wind and STEREO-B. By carrying out a velocity-dispersion analysis on the particles arriving at each location, it was found that energetic particles arriving at STEREO-A were released first and that the release of particles arriving at STEREO-B was delayed by about 50 minutes. Analysis of the expansion of the CME to a wider longitude range indicates that this delay is a result of the time taken for the CME edge to reach the footpoints of the magnetic-field lines connected to STEREO-B. The CME expansion is not seen to reach the magnetic footpoint of Wind at the time of solar-particle release for the particles detected here, suggesting that these particles may not be associated with this CME. Title: Imaging and Spectroscopic Observations of a Filament Channel and the Implications for the Nature of Counter-streamings Authors: Chen, P. F.; Harra, L. K.; Fang, C. Bibcode: 2014ApJ...784...50C Altcode: 2014arXiv1401.4514C The dynamics of a filament channel are observed with imaging and spectroscopic telescopes before and during the filament eruption on 2011 January 29. The extreme ultraviolet (EUV) spectral observations reveal that there are no EUV counterparts of the Hα counter-streamings in the filament channel, implying that the ubiquitous Hα counter-streamings found by previous research are mainly due to longitudinal oscillations of filament threads, which are not in phase between each other. However, there exist larger-scale patchy counter-streamings in EUV along the filament channel from one polarity to the other, implying that there is another component of unidirectional flow (in the range of ±10 km s-1) inside each filament thread in addition to the implied longitudinal oscillation. Our results suggest that the flow direction of the larger-scale patchy counter-streaming plasma in the EUV is related to the intensity of the plage or active network, with the upflows being located at brighter areas of the plage and downflows at the weaker areas. We propose a new method to determine the chirality of an erupting filament on the basis of the skewness of the conjugate filament drainage sites. This method suggests that the right-skewed drainage corresponds to sinistral chirality, whereas the left-skewed drainage corresponds to dextral chirality. Title: Electric current variations and 3D magnetic configuration of coronal jets Authors: Schmieder, Brigitte; Harra, Louise K.; Aulanier, Guillaume; Guo, Yang; Demoulin, Pascal; Moreno-Insertis, Fernando, , Prof Bibcode: 2014cosp...40E2928S Altcode: Coronal jets (EUV) were observed by SDO/AIA on September 17, 2010. HMI and THEMIS measured the vector magnetic field from which we derived the magnetic flux, the phostospheric velocity and the vertical electric current. The magnetic configuration was computed with a non linear force-free approach. The phostospheric current pattern of the recurrent jets were associated with the quasi-separatrix layers deduced from the magnetic extrapolation. The large twisted near-by Eiffel-tower-shape jet was also caused by reconnection in current layers containing a null point. This jet cannot be classified precisely within either the quiescent or the blowout jet types. We will show the importance of the existence of bald patches in the low atmosphere Title: Determining the location of open field regions in active regions and their potential as source regions of the slow solar wind. Authors: Harra, Louise K.; Culhane, J. Leonard; Parnell, Clare; Brooks, David; Platten, Sarah Bibcode: 2014cosp...40E1158H Altcode: One of the significant discoveries from the Hinode EUV Imaging Spectrometer (EIS) instrument is the observation of persistent upflows at edges of active regions. These had been observed in the pre-Hinode era with TRACE imaging, and with SOHO. However, with Hinode these upflows are now observed regularly spectroscopically, and are seen in some form in every active region observed. These tend to occur in regions of low intensity. Although the upflows are always seen, it is far from clear whether they form part of the plasma that flows out into the heliosphere. In this work, we study six active regions in various time periods, with different characteristics - not all are in the same hemisphere, some are located next to coronal holes, others are not. All of them show upflowing plasma. Our aim is to study each active region and compare their physical characteristics. We will then carry out modelling to determine where the truly open magnetic field is, and correlate this with the observations. We want to attempt to distinguish between open and closed field regions. If this can be done in a consistent and fast way, this would prove to be extremely valuable in understanding the source of the slow solar wind. Indeed in terms of a practical use, it could be used as a tool for choosing regions to observe for the future Solar Orbiter mission - the purpose of which is to understand the source of the solar wind from its creation on the Sun through its propagation into the heliosphere Title: Analysing spectroscopically the propagation of a CME from its source on the disk to its impact as it propagates outwards Authors: Harra, Louise K.; Doschek, G. A.; Matthews, Sarah A.; De Pontieu, Bart; Long, David Bibcode: 2014cosp...40E1159H Altcode: We analyse a complex coronal mass ejection observed by Hinode, SDO and IRIS. SDO AIA shows that the eruption occurs between several active regions with flaring occurring in all of them. Hinode EIS observed one of the flaring active regions that shows a fast outwards propagation which is related to the CME lifting off. The eruption is then observed as it propagates away from the Sun, pushing the existing post-flare loops downwards as it goes. Spectroscopic observations are made during this time with IRIS measuring the impact that this CME front has as it pushes the loops downwards. Strong enhancements in the cool Mg II emission at these locations that show complex dynamics. We discuss these new observations in context of CME models. Title: Magnetic Polarity Streams and Subsurface Flows Authors: Howe, R.; Baker, D.; Harra, L.; van Driel-Gesztelyi, L.; Komm, R.; Hill, F.; González Hernández, I. Bibcode: 2013ASPC..478..291H Altcode: An important feature of the solar cycle is the transport of unbalanced magnetic flux from active regions towards the poles, which eventually results in polarity reversal. This transport takes the form of distinct “polarity streams” that are visible in the magnetic butterfly diagram. We compare the poleward migration rate estimated from such streams to that derived from the subsurface meridional flows measured in helioseismic data from the GONG network since 2001, and find that the results are in reasonable agreement. Title: Measuring the Magnetic-Field Strength of the Quiet Solar Corona Using "EIT Waves" Authors: Long, D. M.; Williams, D. R.; Régnier, S.; Harra, L. K. Bibcode: 2013SoPh..288..567L Altcode: 2013arXiv1305.5169L Variations in the propagation of globally propagating disturbances (commonly called "EIT waves") through the low solar corona offer a unique opportunity to probe the plasma parameters of the solar atmosphere. Here, high-cadence observations of two "EIT wave" events taken using the Atmospheric Imaging Assembly (AIA) instrument onboard the Solar Dynamics Observatory (SDO) are combined with spectroscopic measurements from the Extreme ultraviolet Imaging Spectrometer (EIS) onboard the Hinode spacecraft and used to examine the variability of the quiet coronal magnetic-field strength. The combination of pulse kinematics from SDO/AIA and plasma density from Hinode/EIS is used to show that the magnetic-field strength is in the range ≈ 2 - 6 G in the quiet corona. The magnetic-field estimates are then used to determine the height of the pulse, allowing a direct comparison with theoretical values obtained from magnetic-field measurements from the Helioseismic and Magnetic Imager (HMI) onboard SDO using global-scale PFSS and local-scale extrapolations. While local-scale extrapolations predict heights inconsistent with prior measurements, the agreement between observations and the PFSS model indicates that "EIT waves" are a global phenomenon influenced by global-scale magnetic field. Title: Twisting solar coronal jet launched at the boundary of an active region Authors: Schmieder, B.; Guo, Y.; Moreno-Insertis, F.; Aulanier, G.; Yelles Chaouche, L.; Nishizuka, N.; Harra, L. K.; Thalmann, J. K.; Vargas Dominguez, S.; Liu, Y. Bibcode: 2013A&A...559A...1S Altcode: 2013arXiv1309.6514S
Aims: A broad jet was observed in a weak magnetic field area at the edge of active region NOAA 11106 that also produced other nearby recurring and narrow jets. The peculiar shape and magnetic environment of the broad jet raised the question of whether it was created by the same physical processes of previously studied jets with reconnection occurring high in the corona.
Methods: We carried out a multi-wavelength analysis using the EUV images from the Atmospheric Imaging Assembly (AIA) and magnetic fields from the Helioseismic and Magnetic Imager (HMI) both on-board the Solar Dynamics Observatory, which we coupled to a high-resolution, nonlinear force-free field extrapolation. Local correlation tracking was used to identify the photospheric motions that triggered the jet, and time-slices were extracted along and across the jet to unveil its complex nature. A topological analysis of the extrapolated field was performed and was related to the observed features.
Results: The jet consisted of many different threads that expanded in around 10 minutes to about 100 Mm in length, with the bright features in later threads moving faster than in the early ones, reaching a maximum speed of about 200 km s-1. Time-slice analysis revealed a striped pattern of dark and bright strands propagating along the jet, along with apparent damped oscillations across the jet. This is suggestive of a (un)twisting motion in the jet, possibly an Alfvén wave. Bald patches in field lines, low-altitude flux ropes, diverging flow patterns, and a null point were identified at the basis of the jet.
Conclusions: Unlike classical λ or Eiffel-tower-shaped jets that appear to be caused by reconnection in current sheets containing null points, reconnection in regions containing bald patches seems to be crucial in triggering the present jet. There is no observational evidence that the flux ropes detected in the topological analysis were actually being ejected themselves, as occurs in the violent phase of blowout jets; instead, the jet itself may have gained the twist of the flux rope(s) through reconnection. This event may represent a class of jets different from the classical quiescent or blowout jets, but to reach that conclusion, more observational and theoretical work is necessary. Title: Evidence for Hot Fast Flow above a Solar Flare Arcade Authors: Imada, S.; Aoki, K.; Hara, H.; Watanabe, T.; Harra, L. K.; Shimizu, T. Bibcode: 2013ApJ...776L..11I Altcode: 2013arXiv1309.3401I Solar flares are one of the main forces behind space weather events. However, the mechanism that drives such energetic phenomena is not fully understood. The standard eruptive flare model predicts that magnetic reconnection occurs high in the corona where hot fast flows are created. Some imaging or spectroscopic observations have indicated the presence of these hot fast flows, but there have been no spectroscopic scanning observations to date to measure the two-dimensional structure quantitatively. We analyzed a flare that occurred on the west solar limb on 2012 January 27 observed by the Hinode EUV Imaging Spectrometer (EIS) and found that the hot (~30MK) fast (>500 km s-1) component was located above the flare loop. This is consistent with magnetic reconnection taking place above the flare loop. Title: The Location of Non-thermal Velocity in the Early Phases of Large Flares—Revealing Pre-eruption Flux Ropes Authors: Harra, Louise K.; Matthews, Sarah; Culhane, J. L.; Cheung, Mark C. M.; Kontar, Eduard P.; Hara, Hirohisa Bibcode: 2013ApJ...774..122H Altcode: Non-thermal velocity measurements of the solar atmosphere, particularly from UV and X-ray emission lines have demonstrated over the decades that this parameter is important in understanding the triggering of solar flares. Enhancements have often been observed before intensity enhancements are seen. However, until the launch of Hinode, it has been difficult to determine the spatial location of the enhancements to better understand the source region. The Hinode EUV Imaging Spectrometer has the spectral and spatial resolution to allow us to probe the early stages of flares in detail. We analyze four events, all of which are GOES M- or X-classification flares, and all are located toward the limb for ease of flare geometry interpretation. Three of the flares were eruptive and one was confined. In all events, pre-flare enhancement in non-thermal velocity at the base of the active region and its surroundings has been found. These enhancements seem to be consistent with the footpoints of the dimming regions, and hence may be highlighting the activation of a coronal flux rope for the three eruptive events. In addition, pre-flare enhancements in non-thermal velocity were found above the looptops for the three eruptive events. Title: Signatures of Slow Solar Wind Streams from Active Regions in the Inner Corona Authors: Slemzin, V.; Harra, L.; Urnov, A.; Kuzin, S.; Goryaev, F.; Berghmans, D. Bibcode: 2013SoPh..286..157S Altcode: 2012arXiv1203.6756S; 2012SoPh..tmp..144S The identification of solar-wind sources is an important question in solar physics. The existing solar-wind models (e.g., the Wang-Sheeley-Arge model) provide the approximate locations of the solar wind sources based on magnetic field extrapolations. It has been suggested recently that plasma outflows observed at the edges of active regions may be a source of the slow solar wind. To explore this we analyze an isolated active region (AR) adjacent to small coronal hole (CH) in July/August 2009. On 1 August, Hinode/EUV Imaging Spectrometer observations showed two compact outflow regions in the corona. Coronal rays were observed above the active-region coronal hole (ARCH) region on the eastern limb on 31 July by STEREO-A/EUVI and at the western limb on 7 August by CORONAS-Photon/TESIS telescopes. In both cases the coronal rays were co-aligned with open magnetic-field lines given by the potential field source surface model, which expanded into the streamer. The solar-wind parameters measured by STEREO-B, ACE, Wind, and STEREO-A confirmed the identification of the ARCH as a source region of the slow solar wind. The results of the study support the suggestion that coronal rays can represent signatures of outflows from ARs propagating in the inner corona along open field lines into the heliosphere. Title: Are subsurface flows and coronal holes related? Authors: Komm, R.; Howe, R.; González Hernández, I.; Harra, L.; Baker, D.; van Driel-Gesztelyi, L. Bibcode: 2013JPhCS.440a2022K Altcode: We study synoptic maps of solar subsurface flows covering six Carrington rotations (2050 to 2055). The subsurface flows are determined with a ring-diagram analysis of GONG high-resolution Doppler data. We identify the locations of coronal holes in synoptic maps of EUV images at 195Å from the EIT instrument and determine the characteristics of associated subsurface flows. We study two long-lived coronal holes that are present during this epoch. We find that large-scale patterns are present in the subsurface flows but appear to be unrelated to these coronal holes. The horizontal subsurface flows associated with the two long-lived coronal holes are weakly divergent (upflows) with small cyclonic vorticity. These flows are thus similar to subsurface flows of quiet regions with regard to the vertical flows and similar to flows of active regions with regard to vorticity. Title: Can we detect local helioseismic parameter shifts in coronal holes? Authors: Howe, R.; Haber, D. A.; Bogart, R. S.; Zharkov, S.; Baker, D.; Harra, L.; van Driel-Gesztelyi, L. Bibcode: 2013JPhCS.440a2019H Altcode: Changes in helioseismic mode parameters in active regions and across the solar disk are well documented, but local magnetic activity and geometric effects may not account for all of the scatter seen in the results. We use results from the Helioseismic and Magnetic Imager ring-diagram pipeline for Carrington rotation 2113 to look for differences in mode amplitude and frequency between coronal holes and other quiet-Sun regions. While we do not find a systematic difference, the results do suggest that the correlation between magnetic activity index and mode parameters shows less scatter in coronal hole regions than in general quiet Sun. Title: Subsurface flows associated with non-Joy oriented active regions: a case study Authors: González Hernández, Irene; Komm, Rudolf; van Driel-Gesztelyi, Lidia; Baker, Deborah; Harra, Louise; Howe, Rachel Bibcode: 2013JPhCS.440a2050G Altcode: Non-Joy oriented active regions (ARs) are a challenge for solar magnetic field modelers. Although significant deviations from Joy's law are relatively rare for simple bipolar ARs, understanding the causes of their particularity could be critical for the big picture of the solar dynamo. We explore the possibility of the sub-surface local dynamics being responsible for the significant rotation of these ARs. We apply the ring-diagram technique, a local helioseismology method, to infer the flows under and surrounding a non-Joy oriented AR and present the results of a case study in this paper. Title: Measuring the magnetic field strength of the quiet solar corona using "EIT waves" Authors: Long, David M.; Williams, David R.; Régnier, Stéphane; Harra, Louise K. Bibcode: 2013enss.confE..89L Altcode: Variations in the propagation of globally-propagating disturbances (commonly called "EIT waves") through the low solar corona offer a unique opportunity to probe the plasma parameters of the solar atmosphere. Here, high-cadence observations of two "EIT wave" events taken using SDO/AIA are combined with spectroscopic measurements from Hinode/EIS and used to examine the variability of the quiet coronal magnetic field strength. The combination of pulse kinematics from AIA and plasma density from EIS is used to show that the magnetic field strength is in the range 2-6G in the quiet corona. The magnetic field estimates are then used to determine the height of the pulse, allowing a direct comparison with theoretical values obtained from SDO/HMI magnetic field using PFSS and local-domain extrapolations. While local-scale extrapolations predict heights inconsistent with prior measurements, the agreement between observations and the PFSS model indicates that "EIT waves" are a global phenomenon influenced by global-scale magnetic field. Title: Production of High-Temperature Plasmas During the Early Phases of a C9.7 Flare. II. Bi-directional Flows Suggestive of Reconnection in a Pre-flare Brightening Region Authors: Watanabe, T.; Hara, H.; Sterling, A. C.; Harra, L. K. Bibcode: 2012SoPh..281...87W Altcode: 2012SoPh..tmp..185W The 6 June 2007 16:55 UT flare was well observed with high time-cadence sparse raster scans by the EUV Imaging Spectrometer (EIS) on board the Hinode spacecraft. The observation covers an active region area of 240 arcsec × 240 arcsec with the 1 arcsec slit in about 160 seconds. Title: Non-thermal Response of the Corona to the Magnetic Flux Dispersal in the Photosphere of a Decaying Active Region Authors: Harra, L. K.; Abramenko, V. I. Bibcode: 2012ApJ...759..104H Altcode: We analyzed Solar Dynamics Observatory line-of-sight magnetograms for a decaying NOAA active region (AR) 11451 along with co-temporal Extreme-Ultraviolet Imaging Spectrometer (EIS) data from the Hinode spacecraft. The photosphere was studied via time variations of the turbulent magnetic diffusivity coefficient, η(t), and the magnetic power spectrum index, α, through analysis of magnetogram data from the Helioseismic and Magnetic Imager (HMI). These measure the intensity of the random motions of magnetic elements and the state of turbulence of the magnetic field, respectively. The time changes of the non-thermal energy release in the corona was explored via histogram analysis of the non-thermal velocity, v nt, in order to highlight the largest values at each time, which may indicate an increase in energy release in the corona. We used the 10% upper range of the histogram of v nt (which we called V upp nt) of the coronal spectral line of Fe XII 195 Å. A 2 day time interval was analyzed from HMI data, along with the EIS data for the same field of view. Our main findings are the following. (1) The magnetic turbulent diffusion coefficient, η(t), precedes the upper range of the v nt with the time lag of approximately 2 hr and the cross-correlation coefficient of 0.76. (2) The power-law index, α, of the magnetic power spectrum precedes V upp nt with a time lag of approximately 3 hr and the cross-correlation coefficient of 0.5. The data show that the magnetic flux dispersal in the photosphere is relevant to non-thermal energy release dynamics in the above corona. The results are consistent with the nanoflare mechanism of the coronal heating, due to the time lags being consistent with the process of heating and cooling the loops heated by nanoflares. Title: LEMUR: Large European module for solar Ultraviolet Research. European contribution to JAXA's Solar-C mission Authors: Teriaca, Luca; Andretta, Vincenzo; Auchère, Frédéric; Brown, Charles M.; Buchlin, Eric; Cauzzi, Gianna; Culhane, J. Len; Curdt, Werner; Davila, Joseph M.; Del Zanna, Giulio; Doschek, George A.; Fineschi, Silvano; Fludra, Andrzej; Gallagher, Peter T.; Green, Lucie; Harra, Louise K.; Imada, Shinsuke; Innes, Davina; Kliem, Bernhard; Korendyke, Clarence; Mariska, John T.; Martínez-Pillet, Valentin; Parenti, Susanna; Patsourakos, Spiros; Peter, Hardi; Poletto, Luca; Rutten, Robert J.; Schühle, Udo; Siemer, Martin; Shimizu, Toshifumi; Socas-Navarro, Hector; Solanki, Sami K.; Spadaro, Daniele; Trujillo-Bueno, Javier; Tsuneta, Saku; Dominguez, Santiago Vargas; Vial, Jean-Claude; Walsh, Robert; Warren, Harry P.; Wiegelmann, Thomas; Winter, Berend; Young, Peter Bibcode: 2012ExA....34..273T Altcode: 2011ExA...tmp..135T; 2011arXiv1109.4301T The solar outer atmosphere is an extremely dynamic environment characterized by the continuous interplay between the plasma and the magnetic field that generates and permeates it. Such interactions play a fundamental role in hugely diverse astrophysical systems, but occur at scales that cannot be studied outside the solar system. Understanding this complex system requires concerted, simultaneous solar observations from the visible to the vacuum ultraviolet (VUV) and soft X-rays, at high spatial resolution (between 0.1'' and 0.3''), at high temporal resolution (on the order of 10 s, i.e., the time scale of chromospheric dynamics), with a wide temperature coverage (0.01 MK to 20 MK, from the chromosphere to the flaring corona), and the capability of measuring magnetic fields through spectropolarimetry at visible and near-infrared wavelengths. Simultaneous spectroscopic measurements sampling the entire temperature range are particularly important. These requirements are fulfilled by the Japanese Solar-C mission (Plan B), composed of a spacecraft in a geosynchronous orbit with a payload providing a significant improvement of imaging and spectropolarimetric capabilities in the UV, visible, and near-infrared with respect to what is available today and foreseen in the near future. The Large European Module for solar Ultraviolet Research (LEMUR), described in this paper, is a large VUV telescope feeding a scientific payload of high-resolution imaging spectrographs and cameras. LEMUR consists of two major components: a VUV solar telescope with a 30 cm diameter mirror and a focal length of 3.6 m, and a focal-plane package composed of VUV spectrometers covering six carefully chosen wavelength ranges between 170 Å and 1270 Å. The LEMUR slit covers 280'' on the Sun with 0.14'' per pixel sampling. In addition, LEMUR is capable of measuring mass flows velocities (line shifts) down to 2 km s - 1 or better. LEMUR has been proposed to ESA as the European contribution to the Solar C mission. Title: The EUI instrument on board the Solar Orbiter mission: from breadboard and prototypes to instrument model validation Authors: Halain, J. -P.; Rochus, P.; Renotte, E.; Appourchaux, T.; Berghmans, D.; Harra, L.; Schühle, U.; Schmutz, W.; Auchère, F.; Zhukov, A.; Dumesnil, C.; Delmotte, F.; Kennedy, T.; Mercier, R.; Pfiffner, D.; Rossi, L.; Tandy, J.; BenMoussa, A.; Smith, P. Bibcode: 2012SPIE.8443E..07H Altcode: The Solar Orbiter mission will explore the connection between the Sun and its heliosphere, taking advantage of an orbit approaching the Sun at 0.28 AU. As part of this mission, the Extreme Ultraviolet Imager (EUI) will provide full-sun and high-resolution image sequences of the solar atmosphere at selected spectral emission lines in the extreme and vacuum ultraviolet. To achieve the required scientific performances under the challenging constraints of the Solar Orbiter mission it was required to further develop existing technologies. As part of this development, and of its maturation of technology readiness, a set of breadboard and prototypes of critical subsystems have thus been realized to improve the overall instrument design. The EUI instrument architecture, its major components and sub-systems are described with their driving constraints and the expected performances based on the breadboard and prototype results. The instrument verification and qualification plan will also be discussed. We present the thermal and mechanical model validation, the instrument test campaign with the structural-thermal model (STM), followed by the other instrument models in advance of the flight instrument manufacturing and AIT campaign. Title: The Slow Solar Wind: From Formation on the Sun to the Earth Authors: Harra, L. K.; Fazakerley, A. N.; van Driel-Gesztelyi, L. Bibcode: 2012ASPC..454..421H Altcode: Hinode has discovered a potential source of slow solar wind at the edges of active regions with the X-ray Telescope (XRT) and EUV Imaging spectrometer (EIS) on board Hinode e.g. Sakao et al. (2007), Harra et al. (2008), Doschek et al. (2008). These upflows are long-lasting and exist at the edges of most active regions. In this conference paper we first discuss the onset of the upflows. This is related to newly emerged magnetic flux into an active region. Next we discuss whether the flows that we see on the surface of the Sun actually are transported to the Earth in the slow solar wind. To do this we looked at a number of different examples over a Carrington rotation and tracked the response in the solar wind as measured by the ACE spacecraft at L1. We found that there is a significant enhancement of the in situ solar wind speed for active regions located close to a coronal hole. Title: Helioseismic Investigation of Sub-Photospheric Properties of a Coronal Hole Authors: Zharkov, S.; Harra, L. K.; Sekii, T. Bibcode: 2012ASPC..454...27Z Altcode: We present initial results of our investigation into sub-photospheric properties of an equatorial coronal hole obtained via helioseismic analysis using Hinode and MDI observational data. As at photospheric level coronal holes are characterised by open magnetic field we look for seismic signatures of such fields and compare those to the ones observed in plages. Title: Are subsurface flows and coronal holes related? Authors: Komm, Rudolf W.; Howe, R.; González Hernández, I.; Harra, L.; Baker, D.; van Driel-Gesztelyi, L. Bibcode: 2012shin.confE.120K Altcode: We study subsurface flows measured with a ring-diagram analysis of GONG high-resolution Doppler data. In previous studies, we have focused on the relationship between active regions and subsurface flows associated with them. Synoptic subsurface flow maps show also large-scale patterns that are not obviously associated with active regions. It is unknown whether these flow patterns correlate with any large-scale magnetic features. Here, we explore whether there is a relationship between subsurface flows and coronal features. We analyze synoptic maps of subsurface flows covering 18 Carrington rotations during the years 2006 and 2007 (CR 2038-2055). Long-lived coronal holes are present during this epoch at low latitudes, which are accessible by ring-diagram analysis of GONG data. We compare subsurface flow maps with EIT synoptic maps of EUV images at 195A (http://sun.stanford.edu/synop/EIT/) and will present the latest results. Title: The Creation of Outflowing Plasma in the Corona at Emerging Flux Regions: Comparing Observations and Simulations Authors: Harra, L. K.; Archontis, V.; Pedram, E.; Hood, A. W.; Shelton, D. L.; van Driel-Gesztelyi, L. Bibcode: 2012SoPh..278...47H Altcode: In this paper we analyse the flux emergence that occurred in the following polarity area of an active region on 1 - 2 December 2006. Observations have revealed the existence of fast outflows at the edge of the emerging flux region. We have performed 3-D numerical simulations to study the mechanisms responsible for these flows. The results indicate that these outflows are reconnection jets or pressure-driven outflows, depending on the relative orientation of the magnetic fields in contact (i.e. the emerging flux and the active region's field which is favourable for reconnection on the west side and nearly parallel with the pre-existing field on the east side of the emerging flux). In the observations, the flows are larger on the west side until late in the flux emergence, when the reverse is true. The simulations show that the flows are faster on the west side, but do not show the east flows increasing with time. There is an asymmetry in the expansion of the emerging flux region, which is also seen in the observations. The west side of the emerging flux region expands faster into the corona than the other side. In the simulations, efficient magnetic reconnection occurs on the west side, with new loops being created containing strong downflows that are clearly seen in the observations. On the other side, the simulations show strong compression as the dominant mechanism for the generation of flows. There is evidence of these flows in the observations, but the flows are stronger than the simulations predict at the later stages. There could be additional small-angle reconnection that adds to the flows from the compression, as well as reconnection occurring in larger loops that lie across the whole active region. Title: The Role of Coronal Hole and Active Region Boundaries in Solar Wind Formation Authors: Harra, L. K. Bibcode: 2012ASPC..455..315H Altcode: 2012arXiv1201.4646H Hinode observations have provided a new view of outflows from the Sun. These have been focussed in particular on flows emanating from the edges of active regions. These flows are long lasting and seem to exist to some extent in every active region. The flows measured have values ranging between tens of km s-1 and 200 km s-1. Various explanations have been put forward to explain these flows including reconnection, waves, and compression. Outflows have also been observed in coronal holes and this review will discuss those as well as the interaction of coronal holes with active regions. Although outflowing plasma has been observed in all regions of the Sun from quiet Sun to active regions, it is not clear how much of this plasma contributes to the solar wind. I will discuss various attempts to prove that the outflowing plasma forms part of the solar wind. Title: Flare-associated Energy Exchange Between the Photosphere and Corona Authors: Abramenko, Valentyna; Harra, L. Bibcode: 2012AAS...22020414A Altcode: In recent decades, it has been clearly demonstrated that strong flares in ARs (referred before as chromospheric flares) are not restricted to some closed volume in the chromosphere but rather involve a huge volume from deep sub-photospheric layers to the outer heliosphere. Undoubtedly, there exists interaction and energy exchange between different parts of the volume occupied by a flare, e.g., reconnection between up-welling loops and the pre-existing flux, waves and shocks, seismic response to a flare, momentum distribution and Lorentz Force acting, accelerated particle, heat, X-ray propagation, Poynting flux transport, etc. However, mechanisms of the processes, as well as their relationship with the flare itself (is a phenomenon a prelude to the flare, its consequence or non of such) is not well understood yet. We explore new metrics of the photospheric magnetic field: we monitor the magnetic energy dissipation rate. For three strong flares, we found that the magnetic energy dissipation rate sets to a monotonous ceasing several hours before the flare onset. Assuming nearly gradual energy input, the reduction of the energy dissipation rate implies that somewhere in the active region, the energy is being accumulated. The non-dissipated and accumulated energy amounts to (3 - 10) x 1032 ergs. We presume that at least part of the energy accumulated immediately before the flare is transferred into the corona and further drives the corona to a trigger point when flare occurs. Title: One-dimensional Modeling for Temperature-dependent Upflow in the Dimming Region Observed by Hinode/EUV Imaging Spectrometer Authors: Imada, S.; Hara, H.; Watanabe, T.; Murakami, I.; Harra, L. K.; Shimizu, T.; Zweibel, E. G. Bibcode: 2011ApJ...743...57I Altcode: 2011arXiv1108.5031I We previously found a temperature-dependent upflow in the dimming region following a coronal mass ejection observed by the Hinode EUV Imaging Spectrometer (EIS). In this paper, we reanalyzed the observations along with previous work on this event and provided boundary conditions for modeling. We found that the intensity in the dimming region dramatically drops within 30 minutes from the flare onset, and the dimming region reaches the equilibrium stage after ~1 hr. The temperature-dependent upflows were observed during the equilibrium stage by EIS. The cross-sectional area of the flux tube in the dimming region does not appear to expand significantly. From the observational constraints, we reconstructed the temperature-dependent upflow by using a new method that considers the mass and momentum conservation law and demonstrated the height variation of plasma conditions in the dimming region. We found that a super-radial expansion of the cross-sectional area is required to satisfy the mass conservation and momentum equations. There is a steep temperature and velocity gradient of around 7 Mm from the solar surface. This result may suggest that the strong heating occurred above 7 Mm from the solar surface in the dimming region. We also showed that the ionization equilibrium assumption in the dimming region is violated, especially in the higher temperature range. Title: Lateral Offset of the Coronal Mass Ejections from the X-flare of 2006 December 13 and Its Two Precursor Eruptions Authors: Sterling, Alphonse C.; Moore, Ronald L.; Harra, Louise K. Bibcode: 2011ApJ...743...63S Altcode: Two GOES sub-C-class precursor eruptions occurred within ~10 hr prior to and from the same active region as the 2006 December 13 X4.3-class flare. Each eruption generated a coronal mass ejection (CME) with center laterally far offset (gsim 45°) from the co-produced bright flare. Explaining such CME-to-flare lateral offsets in terms of the standard model for solar eruptions has been controversial. Using Hinode/X-Ray Telescope (XRT) and EUV Imaging Spectrometer (EIS) data, and Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric Coronagraph (LASCO) and Michelson Doppler Imager (MDI) data, we find or infer the following. (1) The first precursor was a "magnetic-arch-blowout" event, where an initial standard-model eruption of the active region's core field blew out a lobe on one side of the active region's field. (2) The second precursor began similarly, but the core-field eruption stalled in the side-lobe field, with the side-lobe field erupting ~1 hr later to make the CME either by finally being blown out or by destabilizing and undergoing a standard-model eruption. (3) The third eruption, the X-flare event, blew out side lobes on both sides of the active region and clearly displayed characteristics of the standard model. (4) The two precursors were offset due in part to the CME originating from a side-lobe coronal arcade that was offset from the active region's core. The main eruption (and to some extent probably the precursor eruptions) was offset primarily because it pushed against the field of the large sunspot as it escaped outward. (5) All three CMEs were plausibly produced by a suitable version of the standard model. Title: Plasma Motions and Heating by Magnetic Reconnection in a 2007 May 19 Flare Authors: Hara, Hirohisa; Watanabe, Tetsuya; Harra, Louise K.; Culhane, J. Leonard; Young, Peter R. Bibcode: 2011ApJ...741..107H Altcode: Based on scanning spectroscopic observations with the Hinode EUV imaging spectrometer, we have found a loop-top hot source, a fast jet nearby, and an inflow structure flowing to the hot source that appeared in the impulsive phase of a long-duration flare at the disk center on 2007 May 19. The hot source observed in Fe XXIII and Fe XXIV emission lines has the electron temperature of 12 MK and density of 1 × 1010 cm-3. It shows excess line broadening, which exceeds the thermal Doppler width by ~100 km s-1, with a weak redshift of ~30 km s-1. We have also observed a blueshifted faint jet whose Doppler velocity exceeds 200 km s-1 with an electron temperature of 9 MK. Coronal plasmas with electron temperature of 1.2 MK and density of 2.5 × 109 cm-3 that flow into the loop-top region with a Doppler velocity of 20 km s-1 have been identified in the Fe XII observation. They disappeared near the hot source, possibly by being heated to the hotter faint jet temperature. From the geometrical relationships of these phenomena, we conclude that they provide evidence for magnetic reconnection that occurs near the loop-top region. The estimated reconnection rate is 0.05-0.1, which supports the Petschek-type magnetic reconnection. Further supporting evidence for the presence of the slow-mode and fast-mode MHD shocks in the reconnection geometry is given based on the observed quantities. Title: LEMUR (Large European Module for solar Ultraviolet Research): a VUV imaging spectrograph for the JAXA Solar-C Mission Authors: Korendyke, Clarence M.; Teriaca, Luca; Doschek, George A.; Harra, Louise K.; Schühle, Udo H.; Shimizu, Toshifumi Bibcode: 2011SPIE.8148E..0IK Altcode: 2011SPIE.8148E..17K LEMUR is a VUV imaging spectrograph with 0.28" resolution. Incident solar radiation is imaged onto the spectrograph slit by a single mirror telescope consisting of a 30-cm steerable f/12 off-axis paraboloid mirror. The spectrograph slit is imaged and dispersed by a highly corrected grating that focuses the solar spectrum over the detectors. The mirror is coated with a suitable multilayer with B4C top-coating providing a reflectance peak around 18.5 nm besides the usual B4C range above 500Å. The grating is formed by two halves, one optimized for performances around 185Å and the other above 500Å. Three intensified CCD cameras will record spectra above 50 nm while a large format CCD array with an aluminum filter will be used around 185Å. Title: Spectroscopic Analysis of Interaction between an Extreme-ultraviolet Imaging Telescope Wave and a Coronal Upflow Region Authors: Chen, F.; Ding, M. D.; Chen, P. F.; Harra, L. K. Bibcode: 2011ApJ...740..116C Altcode: 2011arXiv1107.5630C We report a spectroscopic analysis of an EUV Imaging Telescope (EIT) wave event that occurred in active region 11081 on 2010 June 12 and was associated with an M2.0 class flare. The wave propagated nearly circularly. The southeastern part of the wave front passed over an upflow region near a magnetic bipole. Using EUV Imaging Spectrometer raster observations for this region, we studied the properties of plasma dynamics in the wave front, as well as the interaction between the wave and the upflow region. We found a weak blueshift for the Fe XII λ195.12 and Fe XIII λ202.04 lines in the wave front. The local velocity along the solar surface, which is deduced from the line-of-sight velocity in the wave front and the projection effect, is much lower than the typical propagation speed of the wave. A more interesting finding is that the upflow and non-thermal velocities in the upflow region are suddenly diminished after the transit of the wave front. This implies a significant change of magnetic field orientation when the wave passed. As the lines in the upflow region are redirected, the velocity along the line of sight is diminished as a result. We suggest that this scenario is more in accordance with what was proposed in the field-line stretching model of EIT waves. Title: Spectroscopic Observations of a Coronal Moreton Wave Authors: Harra, Louise K.; Sterling, Alphonse C.; Gömöry, Peter; Veronig, Astrid Bibcode: 2011ApJ...737L...4H Altcode: We observed a coronal wave (EIT wave) on 2011 February 16, using EUV imaging data from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) and EUV spectral data from the Hinode/EUV Imaging Spectrometer (EIS). The wave accompanied an M1.6 flare that produced a surge and a coronal mass ejection (CME). EIS data of the wave show a prominent redshifted signature indicating line-of-sight velocities of ~20 km s-1 or greater. Following the main redshifted wave front, there is a low-velocity period (and perhaps slightly blueshifted), followed by a second redshift somewhat weaker than the first; this progression may be due to oscillations of the EUV atmosphere set in motion by the initial wave front, although alternative explanations may be possible. Along the direction of the EIS slit the wave front's velocity was ~500 km s-1, consistent with its apparent propagation velocity projected against the solar disk as measured in the AIA images, and the second redshifted feature had propagation velocities between ~200 and 500 km s-1. These findings are consistent with the observed wave being generated by the outgoing CME, as in the scenario for the classic Moreton wave. This type of detailed spectral study of coronal waves has hitherto been a challenge, but is now possible due to the availability of concurrent AIA and EIS data. Title: Determining the Solar Source of a Magnetic Cloud Using a Velocity Difference Technique Authors: Harra, L. K.; Mandrini, C. H.; Dasso, S.; Gulisano, A. M.; Steed, K.; Imada, S. Bibcode: 2011SoPh..268..213H Altcode: 2010SoPh..tmp..210H; 2010SoPh..tmp..234H For large eruptions on the Sun, it is often a problem that the core dimming region cannot be observed due to the bright emission from the flare itself. However, spectroscopic data can provide the missing information through the measurement of Doppler velocities. In this paper we analyse the well-studied flare and coronal mass ejection that erupted on the Sun on 13 December 2006 and reached the Earth on 14 December 2006. In this example, although the imaging data were saturated at the flare site itself, by using velocity measurements we could extract information on the core dimming region, as well as on remote dimmings. The purpose of this paper is to determine more accurately the magnetic flux of the solar source region, potentially involved in the ejection, through a new technique. The results of its application are compared to the flux in the magnetic cloud observed at 1 AU, as a way to check the reliability of this technique. We analysed data from the Hinode EUV Imaging Spectrometer to estimate the Doppler velocity in the active region and its surroundings before and after the event. This allowed us to determine a Doppler velocity `difference' image. We used the velocity difference image overlayed on a Michelson Doppler Imager magnetogram to identify the regions in which the blue shifts were more prominent after the event; the magnetic flux in these regions was used as a proxy for the ejected flux and compared to the magnetic cloud flux. This new method provides a more accurate flux determination in the solar source region. Title: Pre-Flare Flows in the Corona Authors: Wallace, A. J.; Harra, L. K.; van Driel-Gesztelyi, L.; Green, L. M.; Matthews, S. A. Bibcode: 2010SoPh..267..361W Altcode: 2010SoPh..tmp..223W; 2010SoPh..tmp..199W Solar flares take place in regions of strong magnetic fields and are generally accepted to be the result of a resistive instability leading to magnetic reconnection. When new flux emerges into a pre-existing active region it can act as a flare and coronal mass ejection trigger. In this study we observed active region 10955 after the emergence of small-scale additional flux at the magnetic inversion line. We found that flaring began when additional positive flux levels exceeded 1.38×1020 Mx (maxwell), approximately 7 h after the initial flux emergence. We focussed on the pre-flare activity of one B-class flare that occurred on the following day. The earliest indication of activity was a rise in the non-thermal velocity one hour before the flare. 40 min before flaring began, brightenings and pre-flare flows were observed along two loop systems in the corona, involving the new flux and the pre-existing active region loops. We discuss the possibility that reconnection between the new flux and pre-existing loops before the flare drives the flows by either generating slow mode magnetoacoustic waves or a pressure gradient between the newly reconnected loops. The subsequent B-class flare originated from fast reconnection of the same loop systems as the pre-flare flows. Title: Fibrillar Chromospheric Spicule-like Counterparts to an Extreme-ultraviolet and Soft X-ray Blowout Coronal Jet Authors: Sterling, Alphonse C.; Harra, Louise K.; Moore, Ronald L. Bibcode: 2010ApJ...722.1644S Altcode: We observe an erupting jet feature in a solar polar coronal hole, using data from Hinode/Solar Optical Telescope (SOT), Extreme Ultraviolet Imaging Spectrometer (EIS), and X-Ray Telescope (XRT), with supplemental data from STEREO/EUVI. From extreme-ultraviolet (EUV) and soft X-ray (SXR) images we identify the erupting feature as a blowout coronal jet: in SXRs it is a jet with a bright base, and in EUV it appears as an eruption of relatively cool (~50,000 K) material of horizontal size scale ~30'' originating from the base of the SXR jet. In SOT Ca II H images, the most pronounced analog is a pair of thin (~1'') ejections at the locations of either of the two legs of the erupting EUV jet. These Ca II features eventually rise beyond 45'', leaving the SOT field of view, and have an appearance similar to standard spicules except that they are much taller. They have velocities similar to that of "type II" spicules, ~100 km s-1, and they appear to have spicule-like substructures splitting off from them with horizontal velocity ~50 km s-1, similar to the velocities of splitting spicules measured by Sterling et al. Motions of splitting features and of other substructures suggest that the macroscopic EUV jet is spinning or unwinding as it is ejected. This and earlier work suggest that a subpopulation of Ca II type II spicules are the Ca II manifestation of portions of larger scale erupting magnetic jets. A different subpopulation of type II spicules could be blowout jets occurring on a much smaller horizontal size scale than the event we observe here. Title: Production of High-temperature Plasmas During the Early Phases of a C9.7 Flare Authors: Watanabe, Tetsuya; Hara, Hirohisa; Sterling, Alphonse C.; Harra, Louise K. Bibcode: 2010ApJ...719..213W Altcode: Explosive chromospheric evaporation is predicted from some current solar flare models. In this paper, we analyze a flare with high time cadence raster scans with the EUV Imaging Spectrometer (EIS) on board the Hinode spacecraft. This observation covers an area of 240'' × 240'', with the 1'' slit in about 160 s. The early phases of a C9.7 flare that occurred on 2007 June 6 were well observed. The purpose of our analysis is to study for the first time the spatially resolved spectra of high-temperature plasma, especially from Fe XXIII and Fe XXIV, allowing us to explore the explosive chromospheric evaporation scenario further. Sections of raster images obtained between 17:20:09 and 17:20:29 (UT) show a few bright patches of emission from Fe XXIII/Fe XXIV lines at the footpoints of the flaring loops; these footpoints were not clearly seen in the images taken earlier, between 17:17:30 and 17:17:49 (UT). Fe XXIII spectra at these footpoints show dominating blueshifted components of -(300 to 400) km s-1, while Fe XV/XIV lines are nearly stationary; Fe XII lines and/or lower temperature lines show slightly redshifted features, and Fe VIII and Si VII to He II lines show ~+50 km s-1 redshifted components. The density of the 1.5-2 MK plasma at these footpoints is estimated to be 3 × 1010 cm-3 by the Fe XIII/XIV line pairs around the maximum of the flare. High-temperature loops connecting the footpoints appear in the Fe XXIII/XXIV images taken over 17:22:49-17:23:08 (UT) which is near the flare peak. Line profiles of these high-temperature lines at this flare peak time show only slowly moving components. The concurrent cooler Fe XVII line at 254.8 Å is relatively weak, indicating the predominance of high-temperature plasma (>107 K) in these loops. The characteristics observed during the early phases of this flare are consistent with the scenario of explosive chromospheric evaporation. Title: The technical challenges of the Solar-Orbiter EUI instrument Authors: Halain, Jean-Philippe; Rochus, Pierre; Appourchaux, Thierry; Berghmans, David; Harra, Louise; Schühle, Udo; Auchère, Frédéric; Zhukov, Andrei; Renotte, Etienne; Defise, Jean-Marc; Rossi, Laurence; Fleury-Frenette, Karl; Jacques, Lionel; Hochedez, Jean-François; Ben Moussa, Ali Bibcode: 2010SPIE.7732E..0RH Altcode: 2010SPIE.7732E..20H The Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter consists of a suite of two high-resolution imagers (HRI) and one dual-band full Sun imager (FSI) that will provide EUV and Lyman-α images of the solar atmospheric layers above the photosphere. The EUI instrument is based on a set of challenging new technologies allowing to reach the scientific objectives and to cope with the hard space environment of the Solar Orbiter mission. The mechanical concept of the EUI instrument is based on a common structure supporting the HRI and FSI channels, and a separated electronic box. A heat rejection baffle system is used to reduce the Sun heat load and provide a first protection level against the solar disk straylight. The spectral bands are selected by thin filters and multilayer mirror coatings. The detectors are 10μm pitch back illuminated CMOS Active Pixel Sensors (APS), best suited for the EUI science requirements and radiation hardness. This paper presents the EUI instrument concept and its major sub-systems. The current developments of the instrument technologies are also summarized. Title: Revealing the Fine Structure of Coronal Dimmings and Associated Flows with Hinode/EIS. Implications for Understanding the Source Regions of Sustained Outflow Following CMEs Authors: Attrill, G. D. R.; Harra, L. K.; van Driel-Gesztelyi, L.; Wills-Davey, M. J. Bibcode: 2010SoPh..264..119A Altcode: 2010SoPh..tmp...80A We study two CME events on 13 and 14 December 2006 that were associated with large-scale dimmings. We study the eruptions from pre-event on 11 December through the recovery on 15 December, using a combination of Hinode/EIS, SOHO/EIT, SOHO/MDI, and MLSO Hα data. The GOES X-class flares obscured the core dimmings, but secondary dimmings developed remote from the active region (AR) in both events. The secondary dimmings are found to be formed by a removal of bright coronal material from loops in the plage region to the East of the AR. Using Hinode/EIS data, we find that the outflows associated with the coronal-dimming regions are highly structured. The concentrated outflows are located at the footpoints of coronal loops (which exist before, and are re-established after, the eruptions), and these are correlated with regions of positive magnetic elements. Comparative study of the Hinode/EIS and SOHO/EIT data shows that the reduction in outflow velocity is consistent with the recovery in intensity of the studied regions. We find that concentrated downflows develop during the recovery phase of the dimmings and are also correlated with the same positive magnetic elements that were previously related to outflows. Title: Response of the Solar Atmosphere to the Emergence of `Serpentine' Magnetic Field Authors: Harra, L. K.; Magara, T.; Hara, H.; Tsuneta, S.; Okamoto, T. J.; Wallace, A. J. Bibcode: 2010SoPh..263..105H Altcode: Active region magnetic flux that emerges to the photosphere from below will show complexity in the structure, with many small-scale fragmented features appearing in between the main bipole and then disappearing. Some fragments seen will be absorbed into the main polarities and others seem to cancel with opposite magnetic field. In this paper we investigate the response of the corona to the behaviour of these small fragments and whether energy through reconnection will be transported into the corona. In order to investigate this we analyse data from the Hinode space mission during flux emergence on 1 - 2 December 2006. At the initial stages of flux emergence several small-scale enhancements (of only a few pixels size) are seen in the coronal line widths and diffuse coronal emission exists. The magnetic flux emerges as a fragmented structure, and coronal loops appear above these structures or close to them. These loops are large-scale structures - most small-scale features predominantly stay within the chromosphere or at the edges of the flux emergence. The most distinctive feature in the Doppler velocity is a strong ring of coronal outflows around the edge of the emerging flux region on the eastern side which is either due to reconnection or compression of the structure. This feature lasts for many hours and is seen in many wavelengths. We discuss the implications of this feature in terms of the onset of persistent outflows from an active region that could contribute to the slow solar wind. Title: Bright Points and Jets in Polar Coronal Holes Observed by the Extreme-Ultraviolet Imaging Spectrometer on Hinode Authors: Doschek, G. A.; Landi, E.; Warren, H. P.; Harra, L. K. Bibcode: 2010ApJ...710.1806D Altcode: We present observations of polar coronal hole bright points (BPs) made with the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The data consist of raster images of BPs in multiple spectral lines from mostly coronal ions, e.g., Fe X-Fe XV. The BPs are observed for short intervals and thus the data are snapshots of the BPs obtained during their evolution. The images reveal a complex unresolved temperature structure (EIS resolution is about 2''), with the highest temperature being about 2 × 106 K. Some BPs appear as small loops with temperatures that are highest near the top. But others are more point-like with surrounding structures. However, the thermal time evolution of the BPs is an important factor in their appearance. A BP may appear quite different at different times. We discuss one BP with an associated jet that is bright enough to allow statistically meaningful measurements. The jet Doppler speed along the line of sight is about 15-20 km s-1. Electron densities of the BPs and the jet are typically near 109 cm-3, which implies path lengths along the line of sight on the order of a few arcsec. We also construct differential emission measure curves for two of the best observed BPs. High spatial resolution (significantly better than 1'') is required to fully resolve the BP structures. Title: An overview of the solar corona during the recent solar minimum and prospective for the new cycle Authors: Harra, Louise K. Bibcode: 2010cosp...38.4153H Altcode: 2010cosp.meet.4153H The current solar minimum has been the deepest since the space age began. This has provided us with an ideal opportunity to observe the solar corona in different conditions with high accuracy instrumentation. The Sun's polar fields are weaker than during previous minimum, and have shrunk in size significantly. The number of sunspots reached their lowest for 75 years with many more spotless days occurring. Equatorial coronal holes were longer lasting during this minimum, some lasting more than 20 rotations. The corona itself during eclipses in the current solar minimum did not appear as a 'classic' dipole as previously was the case. I shall discuss these various observational characteristics and describe how activity is starting to increase. Title: What Coronal Dimming Regions tell us about CMEs? New Results from Hinode Authors: Harra, Louise K. Bibcode: 2010cosp...38.1858H Altcode: 2010cosp.meet.1858H Coronal dimming has been a signature used to determine the source of plasma that forms part of a coronal mass ejection (CME) for many years. Generally dimming is detected through imaging instruments by taking difference images. I discuss in this review spectroscopic measurements made using the EUV Imaging Spectrometer (EIS) onboard Hinode of dimming regions during flares in December 2006. In these cases the velocity measurements allow us to determine the highest flow regions, as well as determine 'dimming' regions within the flare site itself which is often saturated in imaging data. This new method of velocity differencing will allow a new perspective on the dimming mechanism. The dimming recovery is also tracked with spectroscopic data. I will also discuss events from the recent surge of solar activity. Title: Reviewing UK space exploration Authors: Curtis, Jeremy; Harra, Louise; Zarnecki, John; Grady, Monica Bibcode: 2010SpPol..26..113C Altcode: This is an edited version of the Executive Summary of a report produced to advise government ministers on the options for UK involvement in space exploration. It sets out four options - from reduced involvement through robotic-only to a fully integrated human and robotic involvement - and discusses the economic and social benefits of each. Given other countries' interest in pursuing exploration, timing is of the essence. Title: Study of Quiet Sun Through the Solar Atmosphere: From the Chromosphere Up to Coronal Layers Authors: Abbo, L.; Gabriel, A.; Harra, L. Bibcode: 2009ASPC..415..389A Altcode: We analyze intensity maps over a range of temperatures covering the chromosphere to the solar corona, near a polar coronal hole. Using observations from EIS spectrometer on Hinode, we examine the width of the network boundary as a function of temperature. Very preliminary results show that there is a gradual increasing of the network boundary width through the transition region up to coronal layers. Existing observations are being studied and newer observation plans are currently under way. Title: Signatures of interchange reconnection: STEREO, ACE and Hinode observations combined Authors: Baker, D.; Rouillard, A. P.; van Driel-Gesztelyi, L.; Démoulin, P.; Harra, L. K.; Lavraud, B.; Davies, J. A.; Opitz, A.; Luhmann, J. G.; Sauvaud, J. -A.; Galvin, A. B. Bibcode: 2009AnGeo..27.3883B Altcode: 2009arXiv0909.5624B Combining STEREO, ACE and Hinode observations has presented an opportunity to follow a filament eruption and coronal mass ejection (CME) on 17 October 2007 from an active region (AR) inside a coronal hole (CH) into the heliosphere. This particular combination of "open" and closed magnetic topologies provides an ideal scenario for interchange reconnection to take place. With Hinode and STEREO data we were able to identify the emergence time and type of structure seen in the in-situ data four days later. On the 21st, ACE observed in-situ the passage of an ICME with "open" magnetic topology. The magnetic field configuration of the source, a mature AR located inside an equatorial CH, has important implications for the solar and interplanetary signatures of the eruption. We interpret the formation of an "anemone" structure of the erupting AR and the passage in-situ of the ICME being disconnected at one leg, as manifested by uni-directional suprathermal electron flux in the ICME, to be a direct result of interchange reconnection between closed loops of the CME originating from the AR and "open" field lines of the surrounding CH. Title: On-disk signatures of eruptive activity from the Hinode mission Authors: Harra, Louise K. Bibcode: 2009AdSpR..44..446H Altcode: On-disk signatures of eruptive activity have been investigated for many years. These include filament eruptions, flares, coronal waves and dimmings. The Hinode mission is providing a new perspective on eruptive activity on the Sun and its linkage to the Earth. Despite being in a period of solar minimum since the launch of Hinode in September 2006, observations have been made of flares and coronal mass ejections (CMEs). A description of flare and CME triggers are presented, followed by a description of the impact of the eruption on the surrounding corona. A review of the more recent results achieved predominantly from the Hinode space mission are given. Some discussion of the future potential is described as a new solar cycle is beginning a slow start. Title: Evidence from the Extreme-Ultraviolet Imaging Spectrometer for Axial Filament Rotation before a Large Flare Authors: Williams, David R.; Harra, Louise K.; Brooks, David H.; Imada, Shinsuke; Hansteen, Viggo H. Bibcode: 2009PASJ...61..493W Altcode: In this article, we present observations made with the Extreme-ultraviolet Imaging Spectrometer on-board the Hinode solar satellite, of an active region filament in the HeII emission line at 256.32Å. The host active region AR 10930 produces an X-class flare during these observations. We measure Doppler shifts with apparent velocities of up to 20km s-1, which are antisymmetric about the filament length and occur several minutes before the flare's impulsive phase. This is indicative of a rotation of the filament, which is in turn consistent with expansion of a twisted flux rope due to the MHD helical kink instability. This is the first time that such an observation has been possible in this transition-region line, and we note that the signature observed occurs before the first indications of pre-flare activity in the GOES solar soft X-ray flux, suggesting that the filament begins to destabilise in tandem with a reorganization of the local magnetic field. We suggest that this expansion is triggered by the decrease of magnetic tension around, and/or total pressure above, the filament. Title: Hinode ``a new solar observatory in space'' Authors: Tsuneta, S.; Harra, L. K.; Masuda, S. Bibcode: 2009cwse.conf...63T Altcode: Since its launch in September 2006, the Japan-US-UK solar physics satellite, Hinode, has continued its observation of the sun, sending back solar images of unprecedented clarity every day. Hinode is equipped with three telescopes, a visible light telescope, an X-ray telescope, and an extreme ultraviolet imaging spectrometer. The Hinode optical telescope has a large primary mirror measuring 50 centimeters in diameter and is the world's largest space telescope for observing the sun and its vector magnetic fields. The impact of Hinode as an optical telescope on solar physics is comparable to that of the Hubble Space Telescope on optical astronomy. While the optical telescope observes the sun's surface, the Hinode X-ray telescope captures images of the corona and the high-temperature flares that range between several million and several tens of millions of degrees. The telescope has captured coronal structures that are clearer than ever. The Hinode EUV imaging spectrometer possesses approximately ten times the sensitivity and four times the resolution of a similar instrument on the SOHO satellite. The source of energy for the sun is in the nuclear fusion reaction that takes place at its core. Here temperature drops closer to the surface, where the temperature measures about 6,000 degrees. Mysteriously, the temperature starts rising again above the surface, and the temperature of the corona is exceptionally high, several millions of degrees. It is as if water were boiling fiercely in a kettle placed on a stove with no fire, inconceivable as it may sound. The phenomenon is referred to as the coronal heating problem, and it is one of the major astronomical mysteries. The Hinode observatory was designed to solve this mystery. It is expected that Hinode would also provide clues to unraveling why strong magnetic fields are formed and how solar flares are triggered. An overview on the initial results from Hinode is presented. Dynamic video pictures captured by Hinode can be viewed on the website of the National Astronomical Observatory of Japan (NAOJ) at http://hinode.nao.ac.jp/index_e.shtml Title: POLAR investigation of the Sun—POLARIS Authors: Appourchaux, T.; Liewer, P.; Watt, M.; Alexander, D.; Andretta, V.; Auchère, F.; D'Arrigo, P.; Ayon, J.; Corbard, T.; Fineschi, S.; Finsterle, W.; Floyd, L.; Garbe, G.; Gizon, L.; Hassler, D.; Harra, L.; Kosovichev, A.; Leibacher, J.; Leipold, M.; Murphy, N.; Maksimovic, M.; Martinez-Pillet, V.; Matthews, B. S. A.; Mewaldt, R.; Moses, D.; Newmark, J.; Régnier, S.; Schmutz, W.; Socker, D.; Spadaro, D.; Stuttard, M.; Trosseille, C.; Ulrich, R.; Velli, M.; Vourlidas, A.; Wimmer-Schweingruber, C. R.; Zurbuchen, T. Bibcode: 2009ExA....23.1079A Altcode: 2008ExA...tmp...40A; 2008arXiv0805.4389A The POLAR Investigation of the Sun (POLARIS) mission uses a combination of a gravity assist and solar sail propulsion to place a spacecraft in a 0.48 AU circular orbit around the Sun with an inclination of 75° with respect to solar equator. This challenging orbit is made possible by the challenging development of solar sail propulsion. This first extended view of the high-latitude regions of the Sun will enable crucial observations not possible from the ecliptic viewpoint or from Solar Orbiter. While Solar Orbiter would give the first glimpse of the high latitude magnetic field and flows to probe the solar dynamo, it does not have sufficient viewing of the polar regions to achieve POLARIS’s primary objective: determining the relation between the magnetism and dynamics of the Sun’s polar regions and the solar cycle. Title: Coronal Nonthermal Velocity Following Helicity Injection Before an X-Class Flare Authors: Harra, L. K.; Williams, D. R.; Wallace, A. J.; Magara, T.; Hara, H.; Tsuneta, S.; Sterling, A. C.; Doschek, G. A. Bibcode: 2009ApJ...691L..99H Altcode: We explore the "pre-flare" behavior of the corona in a three-day period building up to an X-class flare on 2006 December 13 by analyzing EUV spectral profiles from the Hinode EUV Imaging Spectrometer (EIS) instrument. We found an increase in the coronal spectral line widths, beginning after the time of saturation of the injected helicity as measured by Magara & Tsuneta. In addition, this increase in line widths (indicating nonthermal motions) starts before any eruptive activity occurs. The Hinode EIS has the sensitivity to measure changes in the buildup to a flare many hours before the flare begins. Title: Flux Rope Eruption From the Sun to the Earth: What do Reversals in the Azimuthal Magnetic Field Gradient Tell us About the Evolution of the Magnetic Structure? Authors: Steed, K.; Owen, C. J.; Harra, L. K.; Green, L. M.; Dasso, S.; Walsh, A. P.; Démoulin, P.; van Driel-Gesztelyi, L. Bibcode: 2008AGUFMSH23B1638S Altcode: Using ACE in situ data we identify and describe an interplanetary magnetic cloud (MC) observed near Earth on 13 April 2006. We also use multi-instrument and multi-wavelength observations from SOHO, TRACE and ground-based solar observatories to determine the solar source of this magnetic cloud. A launch window for the MC between 9 and 11 April 2006 was estimated from the propagation time of the ejecta observed near Earth. A number of large active regions were present on the Sun during this period, which were initially considered to be the most likely candidate source regions of the MC. However, it was determined that the solar source of the MC was a small, spotless active region observed in the Northern Hemisphere. Following an eruption from this region on 11 April 2006, the ACE spacecraft detected, 59 h later, the passage of the MC, preceded by the arrival of a weak, forward fast shock. The link between the eruption in this active region and the interplanetary MC is supported by several pieces of evidence, including the location of the solar source near to the disk centre and to the east of the central meridian (in agreement with the spacecraft trajectory through the western leg of the magnetic cloud), the propagation time of the ejecta, the agreement between the amount of flux in the magnetic cloud and in the active region, and the agreement between the signs of helicity of the magnetic cloud and the active region (which differs from the sign of helicity of each of the other active regions on the Sun at this time). In addition, the active region is located on the boundary of a coronal hole, and a high speed solar wind stream originating from this region is observed near Earth shortly after the passage of the magnetic cloud. This event highlights the complexities associated with locating the solar source of an ICME observed near Earth, and serves to emphasise that it is the combination of a number of physical characteristics and signatures that is important for successfully tying together the Earth-end and the Sun-end of an event. Further investigation of this MC has revealed some sub-structure towards its centre, observed as a small scale reversal of the azimuthal magnetic field of the MC, similar to that reported by Dasso et al., 2007. We explore several possible explanations for this signature, including the occurrence of multiple flux ropes and/or warping of the magnetic cloud. We also consider whether magnetic reconnection plays a role in creating the geometry that would explain these observations. Title: The Recovery of CME-Related Dimmings and the ICME's Enduring Magnetic Connection to the Sun Authors: Attrill, G. D. R.; van Driel-Gesztelyi, L.; Démoulin, P.; Zhukov, A. N.; Steed, K.; Harra, L. K.; Mandrini, C. H.; Linker, J. Bibcode: 2008SoPh..252..349A Altcode: 2008SoPh..tmp..158A It is generally accepted that transient coronal holes (TCHs, dimmings) correspond to the magnetic footpoints of CMEs that remain rooted in the Sun as the CME expands out into the interplanetary space. However, the observation that the average intensity of the 12 May 1997 dimmings recover to their pre-eruption intensity in SOHO/EIT data within 48 hours, whilst suprathermal unidirectional electron heat fluxes are observed at 1 AU in the related ICME more than 70 hours after the eruption, leads us to question why and how the dimmings disappear whilst the magnetic connectivity is maintained. We also examine two other CME-related dimming events: 13 May 2005 and 6 July 2006. We study the morphology of the dimmings and how they recover. We find that, far from exhibiting a uniform intensity, dimmings observed in SOHO/EIT data have a deep central core and a more shallow extended dimming area. The dimmings recover not only by shrinking of their outer boundaries but also by internal brightenings. We quantitatively demonstrate that the model developed by Fisk and Schwadron (Astrophys. J.560, 425, 2001) of interchange reconnections between "open" magnetic field and small coronal loops is a strong candidate for the mechanism facilitating the recovery of the dimmings. This process disperses the concentration of "open" magnetic field (forming the dimming) out into the surrounding quiet Sun, thus recovering the intensity of the dimmings whilst still maintaining the magnetic connectivity to the Sun. Title: Why are CMEs large-scale coronal events: nature or nurture? Authors: van Driel-Gesztelyi, L.; Attrill, G. D. R.; Démoulin, P.; Mandrini, C. H.; Harra, L. K. Bibcode: 2008AnGeo..26.3077V Altcode: The apparent contradiction between small-scale source regions of, and large-scale coronal response to, coronal mass ejections (CMEs) has been a long-standing puzzle. For some, CMEs are considered to be inherently large-scale events eruptions in which a number of flux systems participate in an unspecified manner, while others consider magnetic reconnection in special global topologies to be responsible for the large-scale response of the lower corona to CME events. Some of these ideas may indeed be correct in specific cases. However, what is the key element which makes CMEs large-scale? Observations show that the extent of the coronal disturbance matches the angular width of the CME an important clue, which does not feature strongly in any of the above suggestions. We review observational evidence for the large-scale nature of CME source regions and find them lacking. Then we compare different ideas regarding how CMEs evolve to become large-scale. The large-scale magnetic topology plays an important role in this process. There is amounting evidence, however, that the key process is magnetic reconnection between the CME and other magnetic structures. We outline a CME evolution model, which is able to account for all the key observational signatures of large-scale CMEs and presents a clear picture how large portions of the Sun become constituents of the CME. In this model reconnection is driven by the expansion of the CME core resulting from an over-pressure relative to the pressure in the CME's surroundings. This implies that the extent of the lower coronal signatures match the final angular width of the CME. Title: Locating the solar source of 13 April 2006 magnetic cloud Authors: Steed, K.; Owen, C. J.; Harra, L. K.; Green, L. M.; Dasso, S.; Walsh, A. P.; Démoulin, P.; van Driel-Gesztelyi, L. Bibcode: 2008AnGeo..26.3159S Altcode: Using Advanced Composition Explorer (ACE) in situ data we identify and describe an interplanetary magnetic cloud (MC) observed near Earth on 13 April 2006. We also use multi-instrument and multi-wavelength observations from the Solar and Heliospheric Observatory (SOHO), the Transition Region and Coronal Explorer (TRACE) and ground-based solar observatories to determine the solar source of this magnetic cloud. A launch window for the MC between 9 and 11 April 2006 was estimated from the propagation time of the ejecta observed near Earth. A number of large active regions (ARs) were present on the Sun during this period, which were initially considered to be the most likely candidate source regions of the MC. However, it was determined that the solar source of the MC was a small, spotless active region observed in the Northern Hemisphere. Following an eruption from this region on 11 April 2006, the ACE spacecraft detected, 59 h later, the passage of the MC, preceded by the arrival of a weak, forward fast shock. The link between the eruption in this active region and the interplanetary MC is supported by several pieces of evidence, including the location of the solar source near to the disk centre and to the east of the central meridian (in agreement with the spacecraft trajectory through the western leg of the magnetic cloud), the propagation time of the ejecta, the agreement between the amount of flux in the magnetic cloud and in the active region, and the agreement between the signs of helicity of the magnetic cloud and the active region (which differs from the sign of helicity of each of the other active regions on the Sun at this time). In addition, the active region is located on the boundary of a coronal hole, and a high speed solar wind stream originating from this region is observed near Earth shortly after the passage of the magnetic cloud. Title: Multi-scale reconnections in a complex CME Authors: van Driel-Gesztelyi, L.; Goff, C. P.; Démoulin, P.; Culhane, J. L.; Matthews, S. A.; Harra, L. K.; Mandrini, C. H.; Klein, K. -L.; Kurokawa, H. Bibcode: 2008AdSpR..42..858V Altcode: A series of three flares of GOES class M, M and C, and a CME were observed on 20 January 2004 occurring in close succession in NOAA 10540. Types II, III, and N radio bursts were associated. We use the combined observations from TRACE, EIT, Hα images from Kwasan Observatory, MDI magnetograms, GOES, and radio observations from Culgoora and Wind/ WAVES to understand the complex development of this event. We reach three main conclusions. First, we link the first two impulsive flares to tether-cutting reconnections and the launch of the CME. This complex observation shows that impulsive quadrupolar flares can be eruptive. Second, we relate the last of the flares, an LDE, to the relaxation phase following forced reconnections between the erupting flux rope and neighbouring magnetic field lines, when reconnection reverses and restores some of the pre-eruption magnetic connectivities. Finally, we show that reconnection with the magnetic structure of a previous CME launched about 8 h earlier injects electrons into open field lines having a local dip and apex (located at about six solar radii height). This is observed as an N-burst at decametre radio wavelengths. The dipped shape of these field lines is due to large-scale magnetic reconnection between expanding magnetic loops and open field lines of a neighbouring streamer. This particular situation explains why this is the first N-burst ever observed at long radio wavelengths. Title: Study of the Physical Properties of Coronal ``Waves'' and Associated Dimmings Authors: Attrill, G. D. R.; Harra, L. K.; van Driel-Gesztelyi, L.; Williams, D.; Alexeev, I. V. Bibcode: 2008ASPC..397..126A Altcode: We present results from our study run by Hinode, designed to obtain information on the physical properties of the diffuse bright fronts known as ``EIT coronal waves'' and their associated dimmings. We analyse data obtained during a frustrated eruption event on 5th May 2007. The event produces a bright front as well as deep and shallow dimmings. We show that the dimmings of this frustrated eruption show similar physical properties to those observed in textbook ``EIT coronal wave'' events. The Hinode/EIS data show that both the deep and shallow dimmings associated with this frustrated eruption show blue-shifted velocities. It is therefore consistent that, like the deep core dimmings, the widespread shallow dimmings observed with many textbook coronal ``wave'' events may also be due to plasma outflows. Title: First Results From Hinode Authors: Matthews, S. A.; Davis, J. M.; Harra, L. K. Bibcode: 2008ASPC..397.....M Altcode: No abstract at ADS Title: Long Duration Flare Observed with Hinode EIS Authors: Culhane, J. L.; Hara, H.; Watanabe, T.; Matsuzaki, K.; Harra, L. K.; Cargill, P.; Mariska, J. T.; Doschek, G. A. Bibcode: 2008ASPC..397..121C Altcode: The first Long Duration Event (LDE) observed with Hinode EIS using a high spectral resolution raster scan is described. The hot plasma features include a cusp-shaped arcade associated with a thermal RHESSI source, cooling post-flare loops, complex plasma flows and an EIT observation that shows expanding loops and inflows characteristic of the standard magnetic reconnection model for solar flares. A Coronal Mass Ejection (CME) is also seen by LASCO. The cusp is well observed in the Ca XVII line and we find enhanced line broadening above this region. Doppler velocity observations for the post-flare loops show both up-flows and down-flows that are interpreted as due to siphon flows. Title: Solar Flares and Coronal Mass Ejections: a New View with Hinode Authors: Harra, L. K. Bibcode: 2008ASPC..397...91H Altcode: Less than a year since Hinode was launched many flares and coronal mass ejections have already been observed, in particular four X-classification flares and fifteen M-classification flares. In this paper I will review the first results on flares and coronal mass ejections from the three instruments on Hinode. I will cover aspects relating to the all important phase building up to a flare, the flare itself and finally the global response of flares. Title: Hinode EIS and XRT Observations of Hot Jets in Coronal Holes - Does the Plasma Escape? Authors: Baker, D.; van Driel-Gesztelyi, L.; Kamio, S.; Culhane, J. L.; Harra, L. K.; Sun, J.; Young, P. R.; Matthews, S. A. Bibcode: 2008ASPC..397...23B Altcode: X-ray jets have been detected in the extreme ultraviolet (EUV) and soft X-ray observations of Hinode's EIS and XRT instruments. Both instruments were used to observe the jets in polar and on-disk coronal holes (CHs). Here, we present a multi-wavelength study of an X-ray jet and its associated bright point found in an equatorial CH on 19 June 2007. Light curves (LCs) in 22 different emission lines were compared to that of Hinode/XRT. As we found in a previous study of two polar X-ray jets, this jet shows a post-jet increase in its EUV LCs. The post-jet enhancement appears cooler than the jet. We suggest this feature arises because the hot plasma of the jet, having failed to reach escape speeds, cools and falls back along the near vertical paths expected to be created by reconnection with open field lines of CHs. In addition to the increase in post-jet EUV intensity, we found tentative evidence of impact heating possibly caused by the fall-back of plasma. Title: Doppler Shifts in the Boundary of the Dimming Region Authors: Imada, S.; Hara, H.; Watanabe, T.; Asai, A.; Kamio, S.; Matsuzaki, K.; Harra, L. K.; Mariska, J. T. Bibcode: 2008ASPC..397..102I Altcode: We present Hinode/EIS raster scan observations of the GOES X3.2 flare that occurred on 2006 December 13. There was a small transient coronal hole which was located 200 arcsec east of the flare arcade. The transient coronal hole was strongly affected by the X-class flare, and the strong upflows were observed in Fe XV line 284.2 Å (log{T/{K}} = 6.3) at the boundary of dimming region. In this paper, we discuss how to obtain the velocity map by correcting the instrumental effects. Title: Non-Gaussian Line Profiles in a Large Solar Flare Observed on 2006 December 13 Authors: Imada, S.; Hara, H.; Watanabe, T.; Asai, A.; Minoshima, T.; Harra, L. K.; Mariska, J. T. Bibcode: 2008ApJ...679L.155I Altcode: We have studied the characteristics of the non-Gaussian line profile of the Fe XIV 274.20 Å line in and around a flare arcade. We found that broad non-Gaussian line profiles associated with redshifts are observed in the flare arcade. There were two typical types of broad line profiles. One was a distorted line profile caused by multiple flows, and the other was a symmetric line profile without any additional component. We successfully distinguished those two types using higher order statistical moments or M—the additional component contribution—defined in this Letter. The distorted/symmetric broad line profiles were preferentially observed in new/old flare loops, respectively. Title: Coronal Plasma Motions near Footpoints of Active Region Loops Revealed from Spectroscopic Observations with Hinode EIS Authors: Hara, Hirohisa; Watanabe, Tetsuya; Harra, Louise K.; Culhane, J. Leonard; Young, Peter R.; Mariska, John T.; Doschek, George A. Bibcode: 2008ApJ...678L..67H Altcode: The solar active region 10938 has been observed from the disk center to the west limb with the Hinode EUV Imaging Spectrometer. In the disk-center observation, subsonic upflow motions of tens of km s-1 and enhanced nonthermal velocities have been found near the footpoints of the active region loops assuming a single Gaussian approximation for the emission-line profiles. When the same part of the active region is observed near the limb, both upflows and enhanced nonthermal velocities essentially decrease. There is a strong correlation between Doppler velocity and nonthermal velocity. Significant deviations from a single Gaussian profile are found in the blue wing of the line profiles for the upflows. These suggest that there are unresolved high-speed upflows. We discuss the implications for coronal heating mechanisms. Title: Outflows at the Edges of Active Regions: Contribution to Solar Wind Formation? Authors: Harra, L. K.; Sakao, T.; Mandrini, C. H.; Hara, H.; Imada, S.; Young, P. R.; van Driel-Gesztelyi, L.; Baker, D. Bibcode: 2008ApJ...676L.147H Altcode: The formation of the slow solar wind has been debated for many years. In this Letter we show evidence of persistent outflow at the edges of an active region as measured by the EUV Imaging Spectrometer on board Hinode. The Doppler velocity ranged between 20 and 50 km s-1 and was consistent with a steady flow seen in the X-Ray Telescope. The latter showed steady, pulsing outflowing material and some transverse motions of the loops. We analyze the magnetic field around the active region and produce a coronal magnetic field model. We determine from the latter that the outflow speeds adjusted for line-of-sight effects can reach over 100 km s-1. We can interpret this outflow as expansion of loops that lie over the active region, which may either reconnect with neighboring large-scale loops or are likely to open to the interplanetary space. This material constitutes at least part of the slow solar wind. Title: 2006 December 17 Long Duration Flare Observed with the Hinode EUV Imaging Spectrometer Authors: Hara, Hirohisa; Watanabe, Tetsuya; Matsuzaki, Keiichi; Harra, Louise K.; Culhane, J. Leonard; Cargill, Peter; Mariska, John T.; Doschek, George A. Bibcode: 2008PASJ...60..275H Altcode: A GOES C-class long-duration flare that occurred near the west limb on 2006 December 17 was observed with the Hinode EUV Imaging Spectrometer (EIS) in raster-scan observations. Cusp-shaped arcades are prominent in the spectroheliogram of the CaXVII emission line at 192.86Å. Spatial relationships between hot flare loops with a cusp apex and cool post flare loops with various temperatures are clearly shown in the EIS observations. We find an enhanced line broadening above the bright loop-top region in the CaXVII observation. The Doppler observations of cooling post flare loops with coronal temperatures show both downflows and upflows along the loops, and these are interpreted as a part of siphon flows. Enhanced nonthermal line broadenings are identified at the top of the post flare loops. Title: Erratum: "Outflows at the Edges of Active Regions: Contribution to Solar Wind Formation?" (ApJ, 676, L147 [2008]) Authors: Harra, L. K.; Sakao, T.; Mandrini, C. H.; Hara, H.; Imada, S.; Young, P. R.; van Driel-Gesztelyi, L.; Baker, D. Bibcode: 2008ApJ...677L.159H Altcode: No abstract at ADS Title: On-disc signatures of eruptive activity: Broad perspective Authors: Harra, Louise K. Bibcode: 2008cosp...37.1180H Altcode: 2008cosp.meet.1180H The Hinode and STEREO missions are providing a new perspective on eruptive activity on the Sun and its linkage to the Earth. This talk will review all aspects eruptive activity from the very small scale (jets in coronal holes) to the large scale (EIT ‘coronal' waves). These different scales of on-disc signatures provide contribution to the fast and slow solar winds and of course the more dramatic coronal mass ejections. Title: Spectroscopic observations of coronal waves and coronal mass ejections Authors: Harra, L. K. Bibcode: 2008AdSpR..41..138H Altcode: It is common to use imaging instruments such as EUV and X-ray imagers and coronagraphs to study large-scale phenomena such as coronal mass ejections and coronal waves. Although high resolution spectroscopy is generally limited to a small field of view, its importance in understanding global phenomena should not be under-estimated. I will review current spectroscopic observations of large-scale dynamic phenomena such as global coronal waves and coronal mass ejections. The aim is to determine plasma parameters such as flows, temperatures and densities to obtain a physical understanding of these phenomena. Title: a New View of the Sun from the Hinode Space Mission Authors: Harra, Louise K. Bibcode: 2008IJMPD..17..693H Altcode: The Japanese/US/UK space mission, Hinode, was launched successfully in September 2006. Now, more than a year after the commissioning of the spacecraft and instruments, Hinode is unveiling a new view of the Sun. Hinode's goal is to help us to understand solar activity, and to link activity on (and below) the surface to the outer corona. This review will describe how the initial results are overturning our understanding of the Sun and will look to the future to anticipate what further discoveries might be made. In particular I will describe the areas of basic magnetohydrodynamic (MHD) processes such as magnetic reconnection and Alfvén waves, the formation of both the fast and slow solar winds and the triggering of flares and coronal mass ejections. Title: Breaking or maintaining magnetic connection of CMEs to the Sun - solar vs. interplanetary signatures tested Authors: van Driel-Gesztelyi, Lidia; Attrill, Gemma; Demoulin, Pascal; Mandrini, Cristina H.; Harra, Louise K. Bibcode: 2008cosp...37.3287V Altcode: 2008cosp.meet.3287V Though their relationship is complex, the presence of suprathermal unior bi-directional electron streams in ICMEs are treated as signatures of magnetic field lines with one or both ends being connected to the Sun, respectively, while their absence is interpreted as disconnection. However, do we have any reliable signature in the solar corona distinguishing between maintained connection and disconnection? We test two solar signatures against interplanetary suprathermal electron signatures in order to establish their relevance. We test the hypothesis that the recovery of Transient Coronal Holes (TCHs, dimming regions corresponding to the footpoints of CMEs) is a signature of magnetic disconnection from the Sun. Through three case studies we quantitatively demonstrate that magnetic reconnections between field lines of the expanded CME magnetic field and small coronal loops can act to disperse the concentration of CME footpoints (forming the dimming region) out into the surrounding quiet Sun, thus recovering the intensity of the dimming region whilst still maintaining the magnetic connectivity to the Sun. This analysis provides evidence that the recovery of coronal dimming regions can, in fact, be simply reconciled with maintained magnetic connectivity to the Sun. However, disconnection can occur when open field lines are involved in reconnection with CMEs. We show through two well-observed case studies that magnetic reconnection between the expanding CME and a nearby coronal hole (CH) is indeed able to disconnect one leg of the expanding CME magnetic structure, as indicated by uni-directional electron streams in their respective ICMEs. Therefore we suggest that brightenings (signatures of reconnection) appearing along a coronal hole boundary in the wake of a CME can be treated as a signature of (at least partial) disconnection of one of the CME legs from the Sun. Title: Coronal Plasma Motions near Footpoints of Active Region Loops Revealed from Spectroscopic Observations with {it Hinode} EIS Authors: Hara, Hirohisa; Watanabe, Tetsuya; Harra, Louise K.; Culhane, J. Leonard; Young, Peter R.; Doschek, G. A.; Mariska, John Bibcode: 2008cosp...37.1175H Altcode: 2008cosp.meet.1175H We have observed the solar active region 10938 from the disk center to the west limb with the Hinode EUV Imaging Spectrometer. In the disk center observation subsonic upflow motions of tens of km s-1 and enhanced nonthermal velocities have been found near the footpoints of the active-region loops assuming a single Gaussian approximation for the emission-line profiles. When the same part of the active region is observed near the limb, both upflows and enhanced nonthermal velocities essentially decrease, clearly showing that the enhanced nonthermal velocities in the disk center observation are mainly due to line-of-sight motions, which are likely parallel to magnetic field lines of the coronal loops. There is a strong correlation between Doppler velocity and nonthermal velocity in the upflow regions. The enhancement in the blue wing of the line profiles is found for the upflows as a significant deviation from a single Gaussian profile. These suggest that there are unresolved high-speed upflows near the footpoints of active region loops. We discuss the implications for coronal heating mechanisms. Title: Structures in flaring loops seen in FeXXIII 263.76A line Authors: Watanabe, T.; Doschek, G. A.; Harra, L. K.; Hara, H. Bibcode: 2007AGUFMSH52C..03W Altcode: EIS observed the highest temperature lines of FeXXIII263.76A, FeXXIV192.10A, 255.10A in the EIS observing wavelengths during a C4.2 flare occurred on 16-Jan-07, as well as an FeXVII line at 254.83A. The raster scan of the flaring area took place during 2:36 - 2:41 UT nearly at the maximum phase of the flare. Comparing a monochromatic FeXXIII raster image with the other high spatial resolution images taken by the instruments on board the Hinode and those by Nobeyama Radio Heliograph, electron precipitation cites are indentified. Foot points with fast chromospheric evaporation are compact at the size of a few arcseconds, and the turbulence still remain around the top of flaring loops. Down flows are also seen in the lower temperature lines just outside the flaring loops. Title: Continuous Plasma Outflows from the Edge of a Solar Active Region as a Possible Source of Solar Wind Authors: Sakao, Taro; Kano, Ryouhei; Narukage, Noriyuki; Kotoku, Jun'ichi; Bando, Takamasa; DeLuca, Edward E.; Lundquist, Loraine L.; Tsuneta, Saku; Harra, Louise K.; Katsukawa, Yukio; Kubo, Masahito; Hara, Hirohisa; Matsuzaki, Keiichi; Shimojo, Masumi; Bookbinder, Jay A.; Golub, Leon; Korreck, Kelly E.; Su, Yingna; Shibasaki, Kiyoto; Shimizu, Toshifumi; Nakatani, Ichiro Bibcode: 2007Sci...318.1585S Altcode: The Sun continuously expels a huge amount of ionized material into interplanetary space as the solar wind. Despite its influence on the heliospheric environment, the origin of the solar wind has yet to be well identified. In this paper, we report Hinode X-ray Telescope observations of a solar active region. At the edge of the active region, located adjacent to a coronal hole, a pattern of continuous outflow of soft-x-ray emitting plasmas was identified emanating along apparently open magnetic field lines and into the upper corona. Estimates of temperature and density for the outflowing plasmas suggest a mass loss rate that amounts to ~1/4 of the total mass loss rate of the solar wind. These outflows may be indicative of one of the solar wind sources at the Sun. Title: The Structure and Dynamics of the Quiet Corona from Observations with the Extreme ultraviolet Imaging Spectrometer Authors: Dere, K. P.; Doschek, G. A.; Mariska, J. T.; Harra, L. K.; Matsuzaki, K.; Hansteen, V.; Thomas, R. J. Bibcode: 2007AGUFMSH53A1046D Altcode: The goal of the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode satellite is to measure such physical parameters as the velocity and density of the solar corona in order to provide an observational basis to understand how coronal plasmas are heated and accelerated. On 2007 January 20, EIS performed a raster of a 128 x 512 arc-sec. area of a quiet region near Sun center. The observing program recorded spectra of He II λ256, formed at 9 × 104 K, and lines of Fe VIII-XV, formed at temperatures spanning the range from 5 × 105 through 2 × 106 K. Maps of intensities, velocities and electron densities derived from these observations are presented and discussed. Intensity maps in He II λ256 show the chromospheric network. Line intensities of Fe X-XIV show small-scale bright points and more extended structures. The intensity map of Fe VIII shows a transition between the two temperatures. The coronal lines reveal regions of high outflow velocities on the order of 100 km s-1 in a compact region and 12 km s-1 in an extended region. The presence of these high velocities in the quiet corona is an entirely new and unexpected result. Electron densities derived from density sensitive line ratios of Fe XII and XIII are typically about 3 - 20×108 cm-3. The highest densities are found in bright, compact areas. For the first time, explosive events in the quiet sun have been observed in the extreme-ultraviolet in He II λ256 profiles and have properties similar to those previously reported. Title: The Structure and Dynamics of the Quiet Corona from Observations with the Extreme Ultraviolet Imaging Spectrometer on Hinode Authors: Dere, Kenneth P.; Doschek, George A.; Mariska, John T.; Hansteen, Viggo H.; Harra, Louise K.; Matsuzaki, Keiichi; Thomas, Roger J. Bibcode: 2007PASJ...59S.721D Altcode: The goal of the Hinode mission is to provide an observational basis for understanding the heating and acceleration of coronal plasmas. On 2007 January 20, the Extreme ultraviolet Imaging Spectrometer performed a raster of a quiet region near Sun center. Maps of intensities, velocities, and electron densities derived from these observations are presented and discussed. Intensity maps in HeII λ 256, formed at 9 × 104 K, show the chromospheric network. Line intensities of FeX-XIV, formed at temperatures from 1-2 × 106 K, show small-scale bright points and more extended structures. The intensity map of FeVIII shows a transition between the two temperatures. The coronal lines reveal regions of high outflow velocities on the order of 100kms-1 in a compact region and 12kms-1 in an extended region. The presence of such high velocities in the quiet corona is an entirely new and unexpected result. Electron densities derived from density sensitive line ratios of FeXII and XIII are typically 3-20 × 108cm-3. The highest densities are found in bright, compact areas. For the first time, explosive events in the quiet sun have been observed in the extreme-ultraviolet in HeII λ 256 profiles. Title: Hinode EUV Study of Jets in the Sun's South Polar Corona Authors: Culhane, Len; Harra, Louise K.; Baker, Deborah; van Driel-Gesztelyi, Lidia; Sun, Jian; Doschek, George A.; Brooks, David H.; Lundquist, Loraine L.; Kamio, Suguru; Young, Peter R.; Hansteen, Viggo H. Bibcode: 2007PASJ...59S.751C Altcode: A number of coronal bright points and associated plasma jet features were seen in an observation of the South polar coronal hole during 2007 January. The 40" wide slot was used at the focus of the Hinode EUV Imaging Spectrometer to provide spectral images for two of these events. Light curves are plotted for a number of emission lines that include He II 256Å (0.079MK) and cover the temperature interval from 0.4MK to 5.0MK. Jet speed measurements indicate values less than the escape velocity. The light curves show a post-jet enhancement in a number of the cooler coronal lines indicating that after a few minutes cooling, the plasma fell back to its original acceleration site. This behavior has not been previously observed by e.g., the Yohkoh Soft X-ray Telescope due to the comparatively high temperature cut-off in its response. The observations are consistent with the existing models that involve magnetic reconnection between emerging flux and the ambient open field lines in the polar coronal hole. However we do not have sufficient coverage of lines from lower temperature ion species to register the Hα-emitting surge material that is associated with some of these models. Title: Temperature and Density Structures of Solar Corona, A Test of Iron Line Diagnostic Capability of EIS Instrument on Board Hinode Authors: Watanabe, Tetsuya; Hara, Hirohisa; Culhane, Len; Harra, Louise K.; Doschek, George A.; Mariska, John T.; Young, Peter R. Bibcode: 2007PASJ...59S.669W Altcode: Increased diagnostic capability of the EUV Imaging Spectrometer (EIS) aboard Hinode (former Solar-B) has been demonstrated with a set of iron emission lines emerging in the two EIS observing wavelength bands (170-210Å and 250-290Å) and their line-intensity ratios. ``Abundance-uncertainty'' free relative emission measure distributions as a function of temperature were deduced using only iron emission lines of various ionization stages. First-light spectra of a small active region show iron lines ranging from FeVIII (185.2Å and 186.6Å) through FeXVII (204.7Å, 254.9Å, and 269.4Å). Spectra of a C-class flare confirms the presence of one of these higher temperature lines (FeXVII at 254.9Å) more clearly, as well showing FeXXIV (192.0Å and 255.1Å) and FeXXIII (263.8Å), which are normally only seen at flare temperatures. Title: On Connecting the Dynamics of the Chromosphere and Transition Region with Hinode SOT and EIS Authors: Hansteen, Viggo H.; de Pontieu, Bart; Carlsson, Mats; McIntosh, Scott; Watanabe, Tetsuya; Warren, Harry P.; Harra, Louise K.; Hara, Hirohisa; Tarbell, Theodore D.; Shine, Dick; Title, Alan M.; Schrijver, Carolus J.; Tsuneta, Saku; Katsukawa, Yukio; Ichimoto, Kiyoshi; Suematsu, Yoshinori; Shimizu, Toshifumi Bibcode: 2007PASJ...59S.699H Altcode: 2007arXiv0711.0487H We use coordinated Hinode SOT/EIS observations that include high-resolution magnetograms, chromospheric, and transition region (TR) imaging, and TR/coronal spectra in a first test to study how the dynamics of the TR are driven by the highly dynamic photospheric magnetic fields and the ubiquitous chromospheric waves. Initial analysis shows that these connections are quite subtle and require a combination of techniques including magnetic field extrapolations, frequency-filtered time-series, and comparisons with synthetic chromospheric and TR images from advanced 3D numerical simulations. As a first result, we find signatures of magnetic flux emergence as well as 3 and 5mHz wave power above regions of enhanced photospheric magnetic field in both chromospheric, transition region, and coronal emission. Title: EUV Emission Lines and Diagnostics Observed with Hinode/EIS Authors: Young, Peter R.; Del Zanna, Giulio; Mason, Helen E.; Dere, Ken P.; Landi, Enrico; Landini, Massimo; Doschek, George A.; Brown, Charles M.; Culhane, Len; Harra, Louise K.; Watanabe, Tetsuya; Hara, Hirohisa Bibcode: 2007PASJ...59S.857Y Altcode: 2007arXiv0706.1857Y Quiet Sun and active region spectra from the Hinode/EIS instrument are presented, and the strongest lines from different temperature regions discussed. A list of emission lines recommended to be included in EIS observation studies is presented based on analysis of blending and diagnostic potential using the CHIANTI atomic database. In addition we identify the most useful density diagnostics from the ions covered by EIS. Title: Discovery of a Temperature-Dependent Upflow in the Plage Region During a Gradual Phase of the X-Class Flare Authors: Imada, Shinsuke; Hara, Hirohisa; Watanabe, Tetsuya; Kamio, Suguru; Asai, Ayumi; Matsuzaki, Keiichi; Harra, Louise K.; Mariska, John T. Bibcode: 2007PASJ...59S.793I Altcode: We present Hinode/EIS raster scan observations of the plage region taken during the gradual phase of the GOES X3.2 flare that occurred on 2006 December 13. The plage region is located 200" east of the flare arcade. The plage region has a small transient coronal hole. The transient coronal hole is strongly affected by an X-class flare, and upflows are observed at its boundary. Multi-wavelength spectral observations allow us to determine velocities from the Doppler shifts at different temperatures. Strong upflows along with stationary plasma have been observed in the FeXV line 284.2Å (log T / K = 6.3) in the plage region. The strong upflows reach almost 150kms-1, which was estimated by a two-component Gaussian fitting. On the other hand, at a lower corona/transition region temperature (HeII, 256.3Å, log T / K = 4.9), very weak upflows, almost stationary, have been observed. We find that these upflow velocities clearly depend on the temperature with the hottest line, FeXV, showing the fastest upflow velocity and the second-highest line, FeXIV, showing the second-highest upflow velocity (130kms-1). All velocities are below the sound speed. The trend of the upflow dependence on temperature dramatically changes at 1MK. These results suggest that heating may have an important role for strong upflow. Title: Coronal Dimming Observed with Hinode: Outflows Related to a Coronal Mass Ejection Authors: Harra, Louise K.; Hara, Hirohisa; Imada, Shinsuke; Young, Peter R.; Williams, David R.; Sterling, Alphonse C.; Korendyke, Clarence; Attrill, Gemma D. R. Bibcode: 2007PASJ...59S.801H Altcode: Coronal dimming has been a signature used to determine the source of plasma that forms part of a coronal mass ejection (CME) for many years. Generally dimming is detected through imaging instruments such as SOHO EIT by taking difference images. Hinode tracked active region 10930 from which there were a series of flares. We combined dimming observations from EIT with Hinode data to show the impact of flares and coronal mass ejections on the region surrounding the flaring active region, and we discuss evidence that the eruption resulted in a prolonged steady outflow of material from the corona. The dimming region shows clear structure with extended loops whose footpoints are the source of the strongest outflow (≈ 40 kms-1). This confirms that the loops that are disrupted during the event do lose plasma and hence are likely to form part of the CME. This is the first time the velocity of the coronal plasma has been measured in an extended dimming region away from the flare core. In addition there was a weaker steady outflow from extended, faint loops outside the active region before the eruption, which is also long lasting. These were disturbed and the velocity increased following the flare. Such outflows could be the source of the slow solar wind. Title: New Evidence for the Role of Emerging Flux in a Solar Filament's Slow Rise Preceding Its CME-producing Fast Eruption Authors: Sterling, Alphonse C.; Harra, Louise K.; Moore, Ronald L. Bibcode: 2007ApJ...669.1359S Altcode: We observe the eruption of a large-scale (~300,000 km) quiet-region solar filament leading to an Earth-directed ``halo'' coronal mass ejection (CME), using data from EIT, CDS, MDI, and LASCO on SOHO and from SXT on Yohkoh. Initially the filament shows a slow (~1 km s-1 projected against the solar disk) and approximately constant velocity rise for about 6 hr, before erupting rapidly, reaching a velocity of ~8 km s-1 over the next ~25 minutes. CDS Doppler data show Earth-directed filament velocities ranging from <20 km s-1 (the noise limit) during the slow-rise phase, to ~100 km s-1 early in the eruption. Beginning within 10 hr prior to the start of the slow rise, localized new magnetic flux emerged near one end of the filament. Near the start of and during the slow-rise phase, soft X-ray (SXR) microflaring occurred repeatedly at the flux-emergence site, and the magnetic arcade over the filament progressively brightened in a fan of illumination in SXRs. These observations are consistent with ``tether-weakening'' reconnection occurring between the newly emerging flux and the overlying arcade field containing the filament, and apparently this reconnection is the cause of the filament's slow rise. We cannot, however, discern whether the transition from slow rise to fast eruption was caused by a final episode of tether-weakening reconnection, or by one or some combination of other possible mechanisms allowed by the observations. Intensity ``dimmings'' and ``brightenings'' occurring both near to and relatively far from the location of the filament are possible signatures of the expansion (``opening'') of the erupting field and its reconnection with overarching field during the eruption. Title: Solar Origins of Interplanetary Coronal Mass Ejections Authors: Harra, L. K. Bibcode: 2007ASPC..369..511H Altcode: Understanding the sources of interplanetary coronal mass ejections (ICMEs) is a vital element of understanding the workings of our solar system. In this paper we review the characteristics of ICMEs and their sources. Title: Coronal ``wave'': A signature of the mechanism making CMEs large-scale in the low corona? Authors: Attrill, G. D. R.; Harra, L. K.; van Driel-Gesztelyi, L.; Démoulin, P.; Wülser, J. -P. Bibcode: 2007AN....328..760A Altcode: We analyse one of the first coronal waves observed by STEREO/EUVI associated with a source region just behind the limb, NOAA 10940. We apply the coronal ``wave'' model proposed by Attrill et al. (2007) to explain the evolution of the observed bright fronts, thereby arguing that the bright fronts and dimmings are due to magnetic reconnections between the expanding CME core and surrounding magnetic structures. We offer a discussion showing that this model provides a mechanism via which CMEs, expanding from a small source region can naturally become large-scale in the low corona. Title: How Does Large Flaring Activity from the Same Active Region Produce Oppositely Directed Magnetic Clouds? Authors: Harra, Louise K.; Crooker, Nancy U.; Mandrini, Cristina H.; van Driel-Gesztelyi, Lidia; Dasso, Sergio; Wang, Jingxiu; Elliott, Heather; Attrill, Gemma; Jackson, Bernard V.; Bisi, Mario M. Bibcode: 2007SoPh..244...95H Altcode: We describe the interplanetary coronal mass ejections (ICMEs) that occurred as a result of a series of solar flares and eruptions from 4 to 8 November 2004. Two ICMEs/magnetic clouds occurring from these events had opposite magnetic orientations. This was despite the fact that the major flares related to these events occurred within the same active region that maintained the same magnetic configuration. The solar events include a wide array of activities: flares, trans-equatorial coronal loop disappearance and reformation, trans-equatorial filament eruption, and coronal hole interaction. The first major ICME/magnetic cloud was predominantly related to the active region 10696 eruption. The second major ICME/magnetic cloud was found to be consistent with the magnetic orientation of an erupting trans-equatorial filament or else a rotation of 160° of a flux rope in the active region. We discuss these possibilities and emphasize the importance of understanding the magnetic evolution of the solar source region before we can begin to predict geoeffective events with any accuracy. Title: Solar Trans-equatorial Activity Authors: Wang, Jingxiu; Zhang, Yuzong; Zhou, Guiping; Harra, Louise K.; Williams, David R.; Jiang, Yunchun Bibcode: 2007SoPh..244...75W Altcode: We have found that solar flares in NOAA active region (AR) 10696 were often associated with large-scale trans-equatorial activities. These trans-equatorial activities appeared to be very common and manifest themselves through i) the formation and eruption of trans-equatorial loops (TELs), ii) the formation and eruption of trans-equatorial filaments (TEFs), and iii) the trans-equatorial brightening (TEB) in the chromosphere. It is determined that the TEF was formed following episodic plasma ejecta from flares occurring in the AR. The TEF eruption was associated with a trans-equatorial flare. All flares in the AR that were accompanied by trans-equatorial activities were associated with halo coronal mass ejections (CMEs). It was noticed that one or several major flares in the AR were followed by an increase of brightness and nonpotentiality of a TEL. These coupled events had a lifetime of more than 12 hours. In addition their associated halo CMEs always had a positive acceleration, indicating prolonged magnetic reconnections in the outer corona at high altitudes. Title: Data Archive of the Hinode Mission Authors: Matsuzaki, K.; Shimojo, M.; Tarbell, T. D.; Harra, L. K.; Deluca, E. E. Bibcode: 2007SoPh..243...87M Altcode: All of the Hinode telemetry data are to be reformatted and archived in the DARTS system at ISAS and mirrored to data centers around the word. The archived data are distributed to users through the Internet. This paper gives an overview of the files in the archive, including the file formats. All formats are portable and have heritage from the previous missions. From the reformatted files, index information is created for faster data search. Users can perform queries based on information contained in the index. This allows for searches to return observations that conform to particular observing conditions. Title: The EUV Imaging Spectrometer for Hinode Authors: Culhane, J. L.; Harra, L. K.; James, A. M.; Al-Janabi, K.; Bradley, L. J.; Chaudry, R. A.; Rees, K.; Tandy, J. A.; Thomas, P.; Whillock, M. C. R.; Winter, B.; Doschek, G. A.; Korendyke, C. M.; Brown, C. M.; Myers, S.; Mariska, J.; Seely, J.; Lang, J.; Kent, B. J.; Shaughnessy, B. M.; Young, P. R.; Simnett, G. M.; Castelli, C. M.; Mahmoud, S.; Mapson-Menard, H.; Probyn, B. J.; Thomas, R. J.; Davila, J.; Dere, K.; Windt, D.; Shea, J.; Hagood, R.; Moye, R.; Hara, H.; Watanabe, T.; Matsuzaki, K.; Kosugi, T.; Hansteen, V.; Wikstol, Ø. Bibcode: 2007SoPh..243...19C Altcode: The EUV Imaging Spectrometer (EIS) on Hinode will observe solar corona and upper transition region emission lines in the wavelength ranges 170 - 210 Å and 250 - 290 Å. The line centroid positions and profile widths will allow plasma velocities and turbulent or non-thermal line broadenings to be measured. We will derive local plasma temperatures and densities from the line intensities. The spectra will allow accurate determination of differential emission measure and element abundances within a variety of corona and transition region structures. These powerful spectroscopic diagnostics will allow identification and characterization of magnetic reconnection and wave propagation processes in the upper solar atmosphere. We will also directly study the detailed evolution and heating of coronal loops. The EIS instrument incorporates a unique two element, normal incidence design. The optics are coated with optimized multilayer coatings. We have selected highly efficient, backside-illuminated, thinned CCDs. These design features result in an instrument that has significantly greater effective area than previous orbiting EUV spectrographs with typical active region 2 - 5 s exposure times in the brightest lines. EIS can scan a field of 6×8.5 arc min with spatial and velocity scales of 1 arc sec and 25 km s−1 per pixel. The instrument design, its absolute calibration, and performance are described in detail in this paper. EIS will be used along with the Solar Optical Telescope (SOT) and the X-ray Telescope (XRT) for a wide range of studies of the solar atmosphere. Title: The Hinode (Solar-B) Mission: An Overview Authors: Kosugi, T.; Matsuzaki, K.; Sakao, T.; Shimizu, T.; Sone, Y.; Tachikawa, S.; Hashimoto, T.; Minesugi, K.; Ohnishi, A.; Yamada, T.; Tsuneta, S.; Hara, H.; Ichimoto, K.; Suematsu, Y.; Shimojo, M.; Watanabe, T.; Shimada, S.; Davis, J. M.; Hill, L. D.; Owens, J. K.; Title, A. M.; Culhane, J. L.; Harra, L. K.; Doschek, G. A.; Golub, L. Bibcode: 2007SoPh..243....3K Altcode: The Hinode satellite (formerly Solar-B) of the Japan Aerospace Exploration Agency's Institute of Space and Astronautical Science (ISAS/JAXA) was successfully launched in September 2006. As the successor to the Yohkoh mission, it aims to understand how magnetic energy gets transferred from the photosphere to the upper atmosphere and results in explosive energy releases. Hinode is an observatory style mission, with all the instruments being designed and built to work together to address the science aims. There are three instruments onboard: the Solar Optical Telescope (SOT), the EUV Imaging Spectrometer (EIS), and the X-Ray Telescope (XRT). This paper provides an overview of the mission, detailing the satellite, the scientific payload, and operations. It will conclude with discussions on how the international science community can participate in the analysis of the mission data. Title: Hinode Euv Study Of Jets In The Sun’s South Polar Corona Authors: Culhane, J. L.; Brooks, D. H.; Doschek, G. A.; Harra, L. K.; van Driel-Gesztelyi, L.; Baker, D.; Lundquist, L. L.; Hansteen, V. H.; Kamio, S. Bibcode: 2007AAS...210.7201C Altcode: 2007BAAS...39..178C Using the Hinode EUV Imaging Spectrometer coronal jets were observed on 20-JAN-2007 over a range of emission lines and corresponding plasma temperatures using the 40 arc sec wide slot images. In this preliminary analysis, jet plasma temperature and emissivity have been estimated while, based on assumptions about the jet morphology, electron density estimates are given and jet velocity measured. The evolution of the jets will be followed in a number of different EUV emission lines and jet energy input as a function of time will be assessed with reference to the magnetic field topologies involved. Title: Coronal dimming observed with Hinode Authors: Harra, Louise; Hara, H.; Young, P.; Williams, D.; Sterling, A.; Attrill, G. Bibcode: 2007AAS...210.6305H Altcode: 2007BAAS...39..172H Coronal dimming has been a technique used to determine the source of plasma that forms part of a coronal mass ejection. Generally dimming is detected through imaging instruments such as SOHO EIT by taking difference images. In a few cases the SOHO-CDS has been used to determine outflowing material, and a decrease in density. Hinode tracked active region 10930 from which there were a series of flares. We combine dimming observations from EIT with Hinode data to show the impact of flares and coronal mass ejections on the region surrounding the flaring active region, and we discuss evidence that the eruption resulted in a prolonged steady outflow of material from the corona. Title: EIS/Hinode Look At Active Region Dynamics Authors: Ugarte-Urra, Ignacio; Warren, H. P.; Brooks, D. H.; Williams, D. R.; Cirtain, J. W.; McKenzie, D. E.; Weber, M.; Hara, H.; Harra, L. K. Bibcode: 2007AAS...210.9429U Altcode: 2007BAAS...39..222U We present some initial results from the Hinode EUV Imaging Spectrometer (EIS) on the heating and cooling of active region loops. The events we observe are part of the short term active region evolution within the span of 50 hours of sit-and-stare observations. We investigate the temporal evolution of the intensity and Doppler shift of spectral lines formed at different temperatures. We then determine time lags and cooling times at various temperature regimes and discuss the results in the context of previous results provided by earlier space missions. This effort is considered a first step into the hydrodynamic modeling of the loop structures. The morphology of the structures is obtained from X-Ray Telescope (XRT) and TRACE images. Title: A Long-duration Flare Observed With Hinode EIS Authors: Hara, Hirohisa; Watanabe, T.; Harra, L.; Culhane, L.; Cargill, P.; Doschek, G.; Mariska, J. Bibcode: 2007AAS...210.6802H Altcode: 2007BAAS...39..175H Long-duration solar flares generally have a cusp apex at the loop top. The cusp shape reflects the topology of magnetic fields near the flare-loop top and it is one of the indirect pieces of evidence supporting the occurrence of the magnetic reconnection process above flare loops. The Hinode EUV Imaging Spectrometer (EIS) observed a long-duration flare that occurred on 2006 Dec 17. We present the first EIS spectroscopic observation of cusp-shaped flare loops. We also report velocity fields around the cusp structures and post-flare loops. Title: Coronal "wave": Magnetic Footprint Of A Cme? Authors: Attrill, Gemma; Harra, L. K.; van Driel-Gesztelyi, L.; Demoulin, P.; Wuelser, J. Bibcode: 2007AAS...210.2921A Altcode: 2007BAAS...39..141A We propose a new mechanism for the generation of "EUV coronal waves". This work is based on new analysis of data from SOHO/EIT, SOHO/MDI & STEREO/EUVI. Although first observed in 1997, the interpretation of coronal waves as flare-induced or CME-driven remains a debated topic. We investigate the properties of two "classical" SOHO/EIT coronal waves in detail. The source regions of the associated CMEs possess opposite helicities & the coronal waves display rotations in opposite senses. We observe deep dimmings near the flare site & also widespread diffuse dimming, accompanying the expansion of the EIT wave. We report a new property of these EIT waves, namely, that they display dual brightenings: persistent ones at the outermost edge of the core dimming regions & simultaneously diffuse brightenings constituting the leading edge of the coronal wave, surrounding the expanding diffuse dimmings. We show that such behaviour is consistent with a diffuse EIT wave being the magnetic footprint of a CME. We propose a new mechanism where driven magnetic reconnections between the skirt of the expanding CME & quiet-Sun magnetic loops generate the observed bright diffuse front. The dual brightenings & widespread diffuse dimming are identified as innate characteristics of this process. In addition we present some of the first analysis of a STEREO/EUVI limb coronal wave. We show how the evolution of the diffuse bright front & dimmings can be understood in terms of the model described above. We show that an apparently stationary part of the bright front can be understood in terms of magnetic interchange reconnections between the expanding CME & the "open" magnetic field of a low-latitude coronal hole. We use both the SOHO/EIT & STEREO/EUVI events to demonstrate that through successive reconnections, this new model provides a natural mechanism via which CMEs can become large-scale in the lower corona. Title: Iron Line Ratio Analysis in an Active Region Authors: Watanabe, Tetsuya; Hara, H.; Culhane, J. L.; Harra, L. K.; Doschek, G. A.; Mariska, J. T.; Young, P. R.; Hinode EIS Team Bibcode: 2007AAS...210.7204W Altcode: 2007BAAS...39..179W Increased diagnostic capability of the EIS instrument on board Hinode (Solar-B) is demonstrated with a set of iron emission lines appearing in the two EIS observing wavelengths (170 - 210 A & 250 - 290 A) and their line intensity ratios. First-light spectra of a small active region show iron lines at the ionization stages of FeVIII (185.2 A & 186.6 A) through FeXVII (204.7 A, 254.9 A, & 269.4 A). Decay phase spectra of a C-class flare confirms the presence of this higher temperature line; FeXVII at 254.9 A more clearly, as well as those lines of flare temperatures; FeXXIV (192.0 A & 255.1 A) and FeXXIII (263.8 A). Title: Coronal Magnetic Connectivity and EUV Dimmings Authors: Zhang, Yuzong; Wang, Jingxiu; Attrill, Gemma D. R.; Harra, Louise K.; Yang, Zhiliang; He, Xiangtao Bibcode: 2007SoPh..241..329Z Altcode: Coronal dimming can be considered to be a disk signature of front-side coronal mass ejections (CMEs) (Thompson et al.: 2000, Geophys. Res. Lett.27, 1431). The study of the magnetic connectivity associated with coronal dimming can shed new light on the magnetic nature of CMEs. In this study, four major flare-CME events on 14 July 2000, 28 October 2003, 7 November 2004, and 15 January 2005 are analyzed. They were all halo CMEs associated with major flare activity in complex active regions (ARs) and produced severe space weather consequences. To explore the magnetic connectivity of these CMEs, global potential-field extrapolations based on the composite synoptic magnetograms from the Michelson Doppler Imager onboard the Solar and Heliospheric Observatory are constructed, and their association with coronal dimming is revealed by the Extreme ultraviolet Imaging Telescope. It is found that each flare-CME event involved interaction of more than ten sets of magnetic-loop systems. These loop systems occupied over 50% of all identified loop systems in the visible hemisphere and covered a wide range of solar longitudes and latitudes. We categorize the loop systems as active-region loops (ARLs), AR-interconnecting loops (ARILs) including transequatorial loops (TLs), and long arcades (LAs) straddling filament channels. A recurring pattern, the saddle-field configuration (SFC), consisting of ARILs, is found to be present in all four major flare-CME events. The magnetic connectivity revealed by this work implies that intercoupling and interaction of multiple flux-loop systems are required for a major CME. For comparison, a simple flare-CME event of 12 May 1997 with a relatively simple magnetic configuration is chosen. Even for this simple flare-CME event, we find that multiple flux-loop systems are also present. Title: A Multiple Flare Scenario where the Classic Long-Duration Flare Was Not the Source of a CME Authors: Goff, C. P.; van Driel-Gesztelyi, L.; Démoulin, P.; Culhane, J. L.; Matthews, S. A.; Harra, L. K.; Mandrini, C. H.; Klein, K. L.; Kurokawa, H. Bibcode: 2007SoPh..240..283G Altcode: A series of flares (GOES class M, M and C) and a CME were observed in close succession on 20 January 2004 in NOAA 10540. Radio observations, which took the form of types II, III and N bursts, were associated with these events. We use the combined observations from TRACE, EIT, Hα images from Kwasan, MDI magnetograms and GOES to understand the complex development of this event. Contrary to a standard interpretation, we conclude that the first two impulsive flares are part of the CME launch process while the following long-duration event flare represents simply the recovery phase. Observations show that the flare ribbons not only separate but also shift along the magnetic inversion line so that magnetic reconnection progresses stepwise to neighboring flux tubes. We conclude that "tether cutting" reconnection in the sheared arcade progressively transforms it to a twisted flux tube, which becomes unstable, leading to a CME. We interpret the third flare, a long-duration event, as a combination of the classical two-ribbon flare with the relaxation process following forced reconnection between the expanding CME structure and neighboring magnetic fields. Title: Decametric N Burst: A Consequence of the Interaction of Two Coronal Mass Ejections Authors: Démoulin, P.; Klein, K. -L.; Goff, C. P.; van Driel-Gesztelyi, L.; Culhane, J. L.; Mandrini, C. H.; Matthews, S. A.; Harra, L. K. Bibcode: 2007SoPh..240..301D Altcode: Radio emissions of electron beams in the solar corona and interplanetary space are tracers of the underlying magnetic configuration and of its evolution. We analyse radio observations from the Culgoora and WIND/WAVES spectrographs, in combination with SOHO/LASCO and SOHO/MDI data, to understand the origin of a type N burst originating from NOAA AR 10540 on January 20, 2004, and its relationship with type II and type III emissions. All bursts are related to the flares and the CME analysed in a previous paper (Goff et al., 2007). A very unusual feature of this event was a decametric type N burst, where a type III-like burst, drifting towards low frequencies (negative drift), changes drift first to positive, then again to negative. At metre wavelengths, i.e., heliocentric distances ≲1.5R⊙, these bursts are ascribed to electron beams bouncing in a closed loop. Neither U nor N bursts are expected at decametric wavelengths because closed quasi-static loops are not thought to extend to distances ≫1.5R⊙. We take the opportunity of the good multi-instrument coverage of this event to analyse the origin of type N bursts in the high corona. Reconnection of the expanding ejecta with the magnetic structure of a previous CME, launched about 8 hours earlier, injects electrons in the same manner as with type III bursts but into open field lines having a local dip and apex. The latter shape was created by magnetic reconnection between the expanding CME and neighbouring (open) streamer field lines. This particular flux tube shape in the high corona, between 5R⊙ and 10R⊙, explains the observed type N burst. Since the required magnetic configuration is only a transient phenomenon formed by reconnection, severe timing and topological constraints are present to form the observed decametric N burst. They are therefore expected to be rare features. Title: Coronal ``Wave'': Magnetic Footprint of a Coronal Mass Ejection? Authors: Attrill, Gemma D. R.; Harra, Louise K.; van Driel-Gesztelyi, Lidia; Démoulin, Pascal Bibcode: 2007ApJ...656L.101A Altcode: We investigate the properties of two ``classical'' EUV Imaging Telescope (EIT) coronal waves. The two source regions of the associated coronal mass ejections (CMEs) possess opposite helicities, and the coronal waves display rotations in opposite senses. We observe deep core dimmings near the flare site and also widespread diffuse dimming, accompanying the expansion of the EIT wave. We also report a new property of these EIT waves, namely, that they display dual brightenings: persistent ones at the outermost edge of the core dimming regions and simultaneously diffuse brightenings constituting the leading edge of the coronal wave, surrounding the expanding diffuse dimmings. We show that such behavior is consistent with a diffuse EIT wave being the magnetic footprint of a CME. We propose a new mechanism where driven magnetic reconnections between the skirt of the expanding CME magnetic field and quiet-Sun magnetic loops generate the observed bright diffuse front. The dual brightenings and the widespread diffuse dimming are identified as innate characteristics of this process. Title: EUI, The Ultraviolet Imaging Telescopes Of Solar Orbiter Authors: Hochedez, J. -F.; Appourchaux, T.; Defise, J. -M.; Harra, L. K.; Schühle, U.; Auchère, F.; Curdt, W.; Hancock, B.; Kretzschmar, M.; Lawrence, G.; Leclec'h, J. -C.; Marsch, E.; Mercier, R.; Parenti, S.; Podladchikova, E.; Ravet, M. -F.; Rochus, P.; Rodriguez, L.; Rouesnel, F.; Solanki, S.; Teriaca, L.; Van Driel, L.; Vial, J. -C.; Winter, B.; Zhukov, A. Bibcode: 2007ESASP.641E..33H Altcode: The scientific objectives of Solar Orbiter rely ubiquitously on EUI, its suite of solar atmosphere imaging telescopes. In the configuration discussed here, EUI includes three co-aligned High Resolution Imagers (HRI) and one Full Sun Imager (FSI). FSI and two HRIs observe in extreme ultraviolet passbands, dominated by coronal emission. Another HRI is designed for the hydrogen Lyman α radiation in the far UV, imaging the Chromosphere and the lower Transition Region. The current EUI design and some of its development challenges are highlighted. EUI profits from co-rotation phases, solar proximity and departure from the ecliptic. In synergy with the other S.O. payload, EUI probes the dynamics of the solar atmosphere, provides context data for all investigations and helps to link in-situ and remote-sensing observations. In short, it serves all four top-level goals of the mission. For these reasons, the EUI suite is keenly anticipated in the European scientific community and beyond. Title: Coronal Mass Ejection Authors: Cargill, P. J.; Harra, L. K. Bibcode: 2007hste.book..118C Altcode: No abstract at ADS Title: Solar flares: the observations Authors: Harra, Louise K. Bibcode: 2007MmSAI..78..236H Altcode: The understanding of solar flares has progressed enormously in the past decades. There is now strong observational evidence that magnetic reconnection is occurring. I will discuss the observational indicators of reconnection - and also the areas where the observations contradict the theory. The actual trigger for flares is not well understood and I will discuss how observations from the recently launched Hinode space mission will be able to address this problem. Title: Using the Evolution of Coronal Dimming Regions to Probe the Global Magnetic Field Topology Authors: Attrill, G.; Nakwacki, M. S.; Harra, L. K.; Van Driel-Gesztelyi, L.; Mandrini, C. H.; Dasso, S.; Wang, J. Bibcode: 2006SoPh..238..117A Altcode: 2006SoPh..tmp...31A We demonstrate that study of the evolving magnetic nature of coronal dimming regions can be used to probe the large-scale magnetic structure involved in the eruption of a coronal mass ejection (CME). We analyse the intensity evolution of coronal dimming regions using 195 Å data from the Extreme ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO). We measure the magnetic flux, using data from the SOHO/Michelson Doppler Imager (MDI), in the regions that seem most likely to be related to plasma removal. Then, we compare these magnetic flux measurements to the flux in the associated magnetic cloud (MC). Here, we present our analysis of the well-studied event on 12 May 1997 that took place just after solar minimum in a simple magnetic configuration. We present a synthesis of results already published and propose that driven "interchange reconnection" between the expanding CME structure with ``open'' field lines of the northern coronal hole region led to the asymmetric temporal and spatial evolution of the two main dimming regions, associated with this event. As a result of this reconnection process, we find the southern-most dimming region to be the principal foot-point of the MC. The magnetic flux from this dimming region and that of the MC are found to be in close agreement within the same order of magnitude, 1021 Mx. Title: The extreme UV imaging spectrometer for the JAXA Solar-B mission Authors: Culhane, J. L.; Doschek, G. A.; Watanabe, T.; Smith, A.; Brown, C.; Hara, H.; Harra, L. K.; James, A. M.; al Janabi, K.; Kent, B.; Korendyke, C.; Lang, J.; Mariska, J.; Myers, S.; Seely, J.; Simnett, G.; Tandy, J.; Thomas, R.; Windt, D. L. Bibcode: 2006SPIE.6266E..0TC Altcode: 2006SPIE.6266E..22C The ISAS/JAXA Solar-B mission includes an Extreme-UV Imaging Spectrometer (EIS). It detects photons in the wavelength ranges 17 - 21 nm and 25 - 29 nm which include emission lines from several highly ionised species that exist at temperatures log T = 4.7, 5.6, 5.8, 5.9 and 6.0 - 7.3 K. Instrument throughput is increased substantially by the use of multilayer coatings optimized for maximum reflectance in the two selected wavelength bands. The use of back-illuminated CCDs provides significantly enhanced quantum efficiency over that previously available from microchannel plate systems. In this paper we will describe the design and operation of the instrument and present its performance parameters e.g. spectral and spatial resolution and sensitivity. Preliminary results of recent calibration measurements will be described. The role of EIS in the Solar-B mission will be illustrated with reference to the anticipated observing strategy for the first three months of the mission which will be outlined. Title: Initiation of the Slow-Rise and Fast-Rise Phases of an Erupting Solar Filamentby Localized Emerging Magnetic Field via Microflaring Authors: Sterling, Alphonse C.; Moore, R. L.; Harra, L. K. Bibcode: 2006SPD....37.0823S Altcode: 2006BAAS...38..234S EUV data from EIT show that a filament of 2001 February 28 underwent aslow-rise phase lasting about 6 hrs, before rapidly erupting in a fast-risephase. Concurrent images in soft X-rays (SXRs) from Yohkoh/SXT show that aseries of three microflares, prominent in SXT images but weak in EIT 195 AngEUV images, occurred near one end of the filament. The first and lastmicroflares occurred respectively in conjunction with the start of theslow-rise phase and the start of the fast-rise phase, and the second microflarecorresponded to a kink in the filament trajectory. Beginning within 10 hoursof the start of the slow rise, new magnetic flux emerged at the location of themicroflaring. This localized new flux emergence and the resulting microflares,consistent with reconnection between the emerging field and the sheared sigmoidcore magnetic field holding the filament, apparently caused the slow rise ofthis field and the transition to explosive eruption. For the first time insuch detail, the observations show this direct action of localized emergingflux in the progressive destabilization of a sheared core field in the onset ofa coronal mass ejection (CME). Similar processes may have occurred in otherrecently-studied events.NASA supported this work through NASA SR&T and SEC GI grants. Title: Transequatorial Filament Eruption and Its Link to a Coronal Mass Ejection Authors: Wang, Jing-Xiu; Zhou, Gui-Ping; Wen, Ya-Yuan; Zhang, Yu-Zong; Wang, Hua-Ning; Deng, Yuan-Yong; Zhang, Jun; Harra, Louise K. Bibcode: 2006ChJAA...6..247W Altcode: We revisit the Bastille Day flare/CME Event of 2000 July 14, and demonstrate that this flare/CME event is not related to only one single active region (AR). Activation and eruption of a huge transequatorial filament are seen to precede the simultaneous filament eruption and flare in the source active region, NOAA AR 9077, and the full halo-CME in the high corona. Evidence of reconfiguration of large-scale magnetic structures related to the event is illustrated by SOHO EIT and Yohkoh SXT observations, as well as, the reconstructed 3D magnetic lines of force based on the force-free assumption. We suggest that the AR filament in AR 9077 was connected to the transequatorial filament. The large-scale magnetic composition related to the transequatorial filament and its sheared magnetic arcade appears to be an essential part of the CME parent magnetic structure. Estimations show that the filament-arcade system has enough magnetic helicity to account for the helicity carried by the related CMEs. In addition, rather global magnetic connectivity, covering almost all the visible range in longitude and a huge span in latitude on the Sun, is implied by the Nançay Radioheliograph (NRH) observations. The analysis of the Bastille Day event suggests that although the triggering of a global CME might take place in an AR, a much larger scale magnetic composition seems to be the source of the ejected magnetic flux, helicity and plasma. The Bastille Day event is the first described example in the literature, in which a transequatorial filament activity appears to play a key role in a global CME. Many tens of halo-CME are found to be associated with transequatorial filaments and their magnetic environment. Title: Connecting the Sun to the Earth Authors: Harra, L.; Owen, C. Bibcode: 2006Obs...126...78H Altcode: No abstract at ADS Title: Non-thermal broadening of coronal emission lines in the onset phase of solar flares and CMEs Authors: Kay, H. R. M.; Matthews, S. A.; Harra, L. K.; Culhane, J. L. Bibcode: 2006A&A...447..719K Altcode: The non-thermal broadening of soft X-ray emission lines is commonly seen during the early stages of solar flares and is thought to be associated with either the initial flare energy release or the evaporation of chromospheric plasma. Here we investigate the magnitude of non-thermal broadening for a sample of 12 flares associated with both eruptive and non-eruptive events, i.e. those with and without associated coronal mass ejections (CMEs), using the Bragg Crystal Spectrometer (BCS) on the Yohkoh spacecraft. The maximum non-thermal broadening of the eruptive flares was found to be on average lower than for the flares which were not associated with CMEs. There was no evidence of any relationship between the maximum non-thermal broadening and the initial CME speed. Title: Observations of Coronal Mass Ejections Authors: Harra, Louise K.; Wang, Jingxiu Bibcode: 2006IAUS..233..455H Altcode: Observations of source regions of coronal mass ejections have progressed enormously in the past decade with the observations from SOHO and Yohkoh. Progress has been made on understanding magnetic helicity, coronal dimming, coronal waves and flares in terms of their relationship to CMEs. Observations have been used to verify and disagree with models such as tether-cutting, kink instabilities and the breakout model. We will describe the observations, recent models, and how future observations from the Solar-B and STEREO missions will address many unanswered questions. Title: Combined analysis of the 15-16 May, 1997, magnetic cloud and of its solar source region Authors: Nakwacki, M. S.; Atrill, G.; Dasso, S.; Mandrini, C. H.; van Driel-Gesztelyi, L.; Harra, L.; Wang, J. Bibcode: 2006BAAA...49...46N Altcode: In this work we analise the structure of the magnetic cloud (MC) observed by Wind between 15-16 May 1997, and the related solar event, a long duration C1.3 flare which ocurred on 12 May 1997. This event presented two dark regions in EUV (dimmings) with asymmetric evolution. The magnetic structure of the MC was modeled using three cylindrical helicoidal models, considering the asymmetry between its front and its final part. We calculate the magnetic flux in the dimmings and their evolution, and the flux through the surface perpendicular to the cloud axis and to the azimuthal direction. Finally, we compare the total flux of both, MC and dimmings, and propose a topological model for the solar event. FULL TEXT IN SPANISH Title: A combined analysis of the magnetic cloud on 15-16 May 1997 and its solar source region Authors: Nakwacki, M. S.; Attrill, G.; Dasso, S.; Mandrini, C. H.; van Driel-Gesztelyi, L.; Harra, L. K.; Wang, J. Bibcode: 2006cosp...36.2479N Altcode: 2006cosp.meet.2479N Coronal Mass Ejections CMEs are the most important short-lived agents that transport magnetic flux from the Sun to the interplanetary medium Thus detailed studies of the solar sources of CMEs and the associated magnetic clouds MCs are an important key to understand and constrain solar and interplanetary models We analyze the magnetic structure of the MC observed on 15-16 May 1997 by the spacecraft Wind and its associated solar event a C1 3 long duration event that occurred on 12 May 1997 in AR8038 Two main dimming regions that exhibit an asymmetric temporal and spatial evolution were observed in association with this event We compute the magnetic flux in the dimmings and follow its evolution using magnetograms from the Michelson Doppler Imager SoHO MDI The MC structure is inferred using three different helical cylindrical models with a significantly different radial twist distribution We also take into account the asymmetry observed between the front and the rear part of the cloud We fit the free parameters of each model comparing models with in situ observations Then we estimate the flux across the surface perpendicular to the axis of the cylinder and the flux across the surface formed by this axis and the cloud radial direction Finally we compare the MC total flux with that corresponding to both observed dimmings By combining our interplanetary measurements and the dimmings flux evolution we propose a topological model for the 12 May eruptive event We discuss the constrains set by solar observations on Title: Multi-scale reconnections in a complex CME Authors: van Driel-Gesztelyi, L.; Goff, C.; Demoulin, P.; Culhane, J. L.; Matthews, S. A.; Harra, L. K.; Mandrini, C. H.; Klein, K. L.; Kurokawa, H. Bibcode: 2006cosp...36.2371V Altcode: 2006cosp.meet.2371V A series of flares GOES class M M and C and a CME were observed on 20-JAN-2004 occurring in close succession in NOAA 10540 Types II III and an N radio bursts were associated We use the combined observations from TRACE EIT H-alpha images from Kwasan Observatory MDI magnetograms GOES and radio observations from Culgoora and Wind WAVES to understand the complex development of this event We link the first two impulsive flares to tether-cutting reconnections and the launch of the CME while the last of the flares an LDE to the relaxation phase following forced reconnections between the erupting flux rope and neighbouring magnetic field lines We show that reconnection with the magnetic structure of a previous CME launched about 8 hours earlier injects electrons into open field lines having a local dip and apex of about 6 solar radii height The dipped shape of these field lines was due to large-scale magnetic reconnection between expanding magnetic loops and open field lines of a neighbouring streamer This particular situation explains the observed decametric N burst and why N-bursts are so rare Title: Large-Scale Magnetic Connectivity in CMEs Authors: Zhang, Yuzong; Wang, Jingxiu; Attrill, Gemma; Harra, Louise K. Bibcode: 2006IAUS..233..357Z Altcode: Five flare/CME events were selected in this study. One is on May 12, 1997, for which there is only two active regions on the visible solar disc, and the magnetic configuration is rather simple. For other cases, many active regions were visible. They are the flare/CME events that occurred on Bastille Day of 2000, Oct. 28, 2003, Nov. 7, 2004 and Jan. 20, 2005. By tracing the spread of EUV dimming, which was obtained by SOHO/EIT 195 Å fixed-difference images, we studied the CME initiation and development on the solar disc. At the same time we reconstructed the 3D magnetic structure of coronal magnetic fields, extrapolated from the observed photospheric magnetograms by SOHO/MDI. In scrutinizing the EUV brightening and dimming propagation from CME initiation sites to large areas with different magnetic connectivities, we determine the overall coupling and interacting of multiple flux systems in the CME processes. Several typical patterns of magnetic connectivity are described and discussed in the view of CME initiation mechanism or mechanisms. Title: The MOSES spectral imager for KuaFu-A Authors: Harra, L. K.; van Driel-Gesztelyi, L.; Cole, R.; Sun, J.; Winter, B.; Hancock, B. Bibcode: 2006cosp...36.3670H Altcode: 2006cosp.meet.3670H We will describe the instrument design for a spectral imager on the KuaFu mission KuaFu s science goals are aimed at understanding space weather with a spacecraft located at L1 and 2 spacecraft in a polar orbit around the Earth The spectral imager will provide crucial information on the source region of coronal mass ejections It will achieve this by measuring the Doppler velocities and intensity over the field of view of the solar activity zone which is geoeffective This allows us to determine whether activity on the Sun does actually releases material into the interplanetary medium BEFORE we observe it in coronagraphs We will summarise the instrument design and the scientific drivers for it Title: Multi spacecraft observations from the Sun to the Earth Authors: Harra, L. K.; Smith, A.; Fazakerley, A. N.; Mandrini, C.; Matthews, S. A. Bibcode: 2005ESASP.588..401H Altcode: 2005tssc.conf..401H No abstract at ADS Title: a Series of Compact Flares with AN Associated CME Authors: Goff, C. P.; van Driel-Geszrelyi, L.; Culhane, J. L.; Matthews, S. A.; Harra, L. K.; Démoulin, P.; Mandrini, C. H.; Kurokawa, H. Bibcode: 2005ESASP.600E.157G Altcode: 2005ESPM...11..157G; 2005dysu.confE.157G No abstract at ADS Title: Erupting Flux Rope, Rising X-Ray Source and a Slow CME on 16 April 2002 Authors: Goff, C. P.; van Driel-Gesztelyi, L.; Harra, L. K.; Matthews, S. A.; Mandrini, C. H. Bibcode: 2005ESASP.600E..46G Altcode: 2005ESPM...11...46G; 2005dysu.confE..46G No abstract at ADS Title: Relating Near-Earth Observations of AN Interplanetary Coronal Mass Ejection to the Conditions at its Site of Origin in the Solar Corona Authors: Fazakerley, A. N.; Harra, L. K.; Culhane, J. L.; van Driel-Gesztelyi, L.; Lucek, E.; Matthews, S. A.; Owen, C. J.; Mazelle, C.; Balogh, A.; Réme, H. Bibcode: 2005ESASP.600E..47F Altcode: 2005dysu.confE..47F; 2005ESPM...11...47F No abstract at ADS Title: X-Ray Observations of Solar Long-Duration Flares Authors: Phillips, K. J. H.; Feldman, U.; Harra, L. K. Bibcode: 2005ApJ...634..641P Altcode: Yohkoh X-ray observations during the several-hour decay of six large solar flares show that the main emitting region is in the form of a bright loop-top source whose spatial extent well after the impulsive stage explains most of the broadening of S XV and Ca XIX X-ray lines, which would otherwise imply nonthermal velocities of 100 km s-1 or more. During the decay of each event, the electron temperature and emission measure decline slowly. For the nearly disk center event of 1992 February 27, the volume increases and the deduced lower limit to the electron density Ne decreases from ~1011 cm-3 to just below 1010 cm-3. The nonuniform emission along the loops indicates that Spitzer heat conduction does not operate. If radiation is the only or main energy-loss mechanism, the lower limits to Ne imply upper limits to radiation cooling times of up to 10 hr, less than the flare decay time, so necessitating a continuing energy input. Although magnetic reconnection of previous broken open loops (the Kopp-Pneuman model) has been widely regarded as the source of energy in such flares, the small nonthermal velocities-only 20-50 km s-1 as indicated by SUMER observations-and the lack of spectroscopic indicators of large inflows or outflows argue against it. Other flare models must also explain the relatively small nonthermal velocities. An alternative picture of loop oscillations recently seen in TRACE and Yohkoh data is proposed for the production of observed nonthermal velocities. Title: Magnetic Fields and Intensity Changes in Coronal Dimming Regions Authors: Attrill, G. D. R.; Narukage, N.; Shibata, K.; Harra, L. K. Bibcode: 2005ESASP.596E..11A Altcode: 2005ccmf.confE..11A No abstract at ADS Title: Explosions on the Sun Authors: Harra, Louise K. Bibcode: 2005aabb.book..375H Altcode: I will describe the most dynamic and highly energetic phenomena in the Solar System - these are the eruptions and flaring that occur on the Sun. They can release as much energy as 10 million volcanoes, and throw out material into the solar system with similar mass to Mount Everest! The theories of what can produce such an explosion are based around the magnetic field that confines the gas. These events can produce emission right across the electromagnetic spectrum. The status of our ability to predict these events is discussed. Title: Flows in the solar atmosphere due to the eruptions on the 15th July, 2002 Authors: Harra, L. K.; Démoulin, P.; Mandrini, C. H.; Matthews, S. A.; van Driel-Gesztelyi, L.; Culhane, J. L.; Fletcher, L. Bibcode: 2005A&A...438.1099H Altcode: Which kind of flows are present during flares? Are they compatible with the present understanding of energy release and which model best describes the observations? We analyze successive flare events in order to answer these questions. The flares were observed in the magnetically complex NOAA active region (AR) 10030 on 15 July 2002. One of them is of GOES X-class. The description of these flares and how they relate to the break-out model is presented in Gary & Moore (2004). The Coronal Diagnostic Spectrometer on board SOHO observed this active region for around 14 h. The observed emission lines provided data from the transition region to the corona with a field of view covering more than half of the active region. In this paper we analyse the spatially resolved flows seen in the atmosphere from the preflare to the flare stages. We find evidence for evaporation occurring before the impulsive phase. During the main phase, the ongoing magnetic reconnection is demonstrated by upflows located at the edges of the flare loops (while downflows are found in the flare loops themselves). We also report the impact of a filament eruption on the atmosphere, with flows up to 300 km s-1 observed at transition-region temperatures in regions well away from the location of the pre-eruptive filament. Our results are consistent with the predictions of the break out model before the impulsive phase of the flare; while, as the flare progresses, the directions of the flows are consistent with flare models invoking evaporation followed by cooling and downward plasma motions in the flare loops. Title: Stability of EUV multilayers to long-term heating, and to energetic protons and neutrons, for extreme solar missions Authors: Rousseau, A. D.; Windt, D. L.; Winter, B.; Harra, L.; Lamoureux, H.; Eriksson, F. Bibcode: 2005SPIE.5900...14R Altcode: We have systematically investigated the thermal and particle stability of several state-of-the-art EUV multilayer coatings suitable for use in high-performance solar instrumentation. Our research has been motivated principally by the performance requirements for extreme solar missions such as Solar Orbiter, an approved ESA mission with an expected launch date of 2013. The goal of this particular mission is to explore the solar atmosphere with both in situ and remote sensing instrumentation at a close encounter. At perihelion the mission will reach 0.2 A.U. providing a unique viewpoint where the instruments can both 'see' and 'feel' the dynamic atmosphere. But the orbit is technically challenging- no remote sensing instrument has been put in such close proximity to the Sun before. Furthermore, the thermal and particle environment will not only be severe but will suffer huge fluctuations as the elliptical orbit changes from 0.2 A.U. to 1.1 A.U. Several of the remote sensing packages on the strawman payload of the mission contain multilayer coatings, thus the stability of these coatings to the expected thermal and particle environment must be established. In this paper, we investigate the impact on the integrity of several candidate EUV multilayer coatings after long-term thermal annealing, and upon exposure to energetic protons and neutrons. In summary, we find no significant degradation in any of the multilayer samples tested. These results suggest that the multilayers we have studied can be safely used for Solar Orbiter or other extreme solar missions. Title: Relating near-Earth observations of an interplanetary coronal mass ejection to the conditions at its site of origin in the solar corona Authors: Fazakerley, A. N.; Harra, L. K.; Culhane, J. L.; van Driel-Gesztelyi, L.; Lucek, E.; Matthews, S. A.; Owen, C. J.; Mazelle, C.; Balogh, A.; Rème, H. Bibcode: 2005GeoRL..3213105F Altcode: A halo coronal mass ejection (CME) was detected on January 20, 2004. We use solar remote sensing data (SOHO, Culgoora) and near-Earth in situ data (Cluster) to identify the CME source event and show that it was a long duration flare in which a magnetic flux rope was ejected, carrying overlying coronal arcade material along with it. We demonstrate that signatures of both the arcade material and the flux rope material are clearly identifiable in the Cluster and ACE data, indicating that the magnetic field orientations changed little as the material traveled to the Earth, and that the methods we used to infer coronal magnetic field configurations are effective. Title: The first observed stellar X-ray flare oscillation: Constraints on the flare loop length and the magnetic field Authors: Mitra-Kraev, U.; Harra, L. K.; Williams, D. R.; Kraev, E. Bibcode: 2005A&A...436.1041M Altcode: 2005astro.ph..3384M We present the first X-ray observation of an oscillation during a stellar flare. The flare occurred on the active M-type dwarf AT Mic and was observed with XMM-Newton. The soft X-ray light curve (0.2-12 keV) is investigated with wavelet analysis. The flare's extended, flat peak shows clear evidence for a damped oscillation with a period of around 750 s, an exponential damping time of around 2000 s, and an initial, relative peak-to-peak amplitude of around 15%. We suggest that the oscillation is a standing magneto-acoustic wave tied to the flare loop, and find that the most likely interpretation is a longitudinal, slow-mode wave, with a resulting loop length of (2.5 ± 0.2)×1010 cm. The local magnetic field strength is found to be 105 ± 50 G. These values are consistent with (oscillation-independent) flare cooling time models and pressure balance scaling laws. Such a flare oscillation provides an excellent opportunity to obtain coronal properties like the size of a flare loop or the local magnetic field strength for the otherwise spatially-unresolved star. Title: A slow coronal mass ejection with rising X-ray source Authors: Goff, C. P.; van Driel-Gesztelyi, L.; Harra, L. K.; Matthews, S. A.; Mandrini, C. H. Bibcode: 2005A&A...434..761G Altcode: An eruptive event, which occurred on 16th April 2002, is discussed. Using images from the Transition Region and Coronal Explorer (TRACE) at 195 Å, we observe a lifting flux rope which gives rise to a slow coronal mass ejection (CME). There are supporting velocity observations from the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO), which illustrate the helical nature of the structure. Additionally a rising coronal hard X-ray source, which is observed with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), is shown to follow the flux rope with a speed of ~60 km s-1. It is also sampled by the CDS slit, although it has no signature in the Fe XIX band. Following the passage of this source, there is evidence from the CDS for down-flowing (cooling) material along newly reconnected loops through Doppler velocity observations, combined with magnetic field modeling. Later, a slow CME is observed with the Large Angle and Spectroscopic Coronagraph (LASCO). We combine a height-time profile of the flux rope at lower altitudes with the slow CME. The rising flux rope speeds up by a factor of 1.7 at the start of the impulsive energy release and goes through further acceleration before reaching 1.5 solar radii. These observations support classical CME scenarios in which the eruption of a filament precedes flaring activity. Cusped flare loops are observed following the erupting flux rope and their altitude increases with time. In addition we find RHESSI sources both below and above the probable location of the reconnection region. Title: Loop length and magnetic field estimates from oscillations detected during an X-ray flare on AT Mic Authors: Mitra-Kraev, U.; Harra, L. K. Bibcode: 2005ESASP.560..821M Altcode: 2005csss...13..821M; 2004astro.ph.10656M We analyse oscillations observed in the X-ray light curve of the late-type star AT Mic. The oscillations occurred during flare maximum. We interpret these oscillations as density perturbations in the flare loop. Applying various models derived for the Sun, the loop length and the magnetic field of the flare can be estimated. We find a period of 740 s, and that the models give similar results (within a factor of 2) for the loop length (~5.4e10 cm) and the magnetic field (~100 G). For the first time, an oscillation of a stellar X-ray flare has been observed and results thus obtained for otherwise unobservable physical parameters. Title: Relationship between X-ray and ultraviolet emission of flares from dMe stars observed by XMM-Newton Authors: Mitra-Kraev, U.; Harra, L. K.; Güdel, M.; Audard, M.; Branduardi-Raymont, G.; Kay, H. R. M.; Mewe, R.; Raassen, A. J. J.; van Driel-Gesztelyi, L. Bibcode: 2005A&A...431..679M Altcode: 2004astro.ph.10592M We present simultaneous ultraviolet and X-ray observations of the dMe-type flaring stars AT Mic, AU Mic, EV Lac, UV Cet and YZ CMi obtained with the XMM-Newton observatory. During 40 h of simultaneous observation we identify 13 flares which occurred in both wave bands. For the first time, a correlation between X-ray and ultraviolet flux for stellar flares has been observed. We find power-law relationships between these two wavelength bands for the flare luminosity increase, as well as for flare energies, with power-law exponents between 1 and 2. We also observe a correlation between the ultraviolet flare energy and the X-ray luminosity increase, which is in agreement with the Neupert effect and demonstrates that chromospheric evaporation is taking place. Title: Preface Authors: Harra, Louise K. Bibcode: 2005AdSpR..36.1359H Altcode: No abstract at ADS Title: An imager with added value for the Solar Orbiter mission Authors: Harra, L. K.; Kankelborg, C. C.; Thomas, R. J.; Fox, J. L.; Winter, B. Bibcode: 2005AdSpR..36.1422H Altcode: Our current ways of observing the Sun with spectrometers and imagers are limited. With a slit spectrometer, we require time to build up a 2-D image which results in temporal blurring. When we use a traditional imager, we have no ability to measure and detect line-of-sight flows or to discriminate contributions from gas at different temperatures in the imager passband, causing spectral confusion of the images. For Solar Orbiter, the combination of an exciting new viewpoint of the Sun, and the best resolution of the corona ever seen, means that we require the best time cadence and velocity information that we can get. The spatial resolution expected from the imager on Solar Orbiter will reach approximately 70 km. At such a resolution in the corona, we expect to see the fundamental magnetic flux tubes, which are predicted to have high velocities. This is also the scale at which we will be able to search for evidence basic physical processes such as magnetic reconnection. We will describe the design of an imager that gives not only high quality images, but also provides simultaneous information about plasma flows and temperature. A prototype instrument is being flown on a NASA sounding rocket next year. The concept will be described, along with some methods of extracting the spectroscopic information. Title: The Solar-B EUV imaging spectrometer and its science goals Authors: Culhane, J. L.; Harra, L. K.; Doschek, G. A.; Mariska, J. T.; Watanabe, T.; Hara, H. Bibcode: 2005AdSpR..36.1494C Altcode: The Solar-B mission includes an Extreme-UV Imaging Spectrometer (EIS). It detects photons in the ranges 170-210 and 250-290 Å which include emission lines from several highly ionised species that exist at temperatures log T = 4.7, 5.6, 5.8, 5.9 and 6.0-7.3 K. In this paper, we will describe the design and operation of the instrument and present its performance parameters, e.g., spectral and spatial resolution and sensitivity. Preliminary results of recent calibration measurements will be described. Its role in the Solar-B mission will be illustrated with reference to several key science topics that the EIS is expected to address. The anticipated observing strategy for the first three months of the mission will be outlined. Title: The Relationship between Prominence Eruptions and Global Coronal Waves Authors: Attrill, G. D. R.; Harra, L. K.; Matthews, S. A.; Foley, C. R.; Sterling, A. C. Bibcode: 2004ASPC..325..409A Altcode: There has been much debate over the physical mechanism for producing global coronal waves (`EIT waves'). In this work, we investigate whether filament eruptions are directly associated with coronal waves. We analyse 45 coronal waves and search for evidence of filament eruptions. We used SOHO-EIT data, and EIT data along with any available ground-based Hα data to search for filament eruptions, and found that more than 50 % of coronal waves are clearly associated with eruptions. The speeds of the coronal waves, and the filament eruptions are similar. We discuss the implications of these results. Title: Effect of solar energetic particle (SEP) events on the radiation exposure levels to aircraft passengers and crew: Case study of 14 July 2000 SEP event Authors: Iles, R. H. A.; Jones, J. B. L.; Taylor, G. C.; Blake, J. B.; Bentley, R. D.; Hunter, R.; Harra, L. K.; Coates, A. J. Bibcode: 2004JGRA..10911103I Altcode: We investigate the circumstances required for aircrew and passengers to experience an increased radiation exposure rate from a solar energetic particle (SEP) event occurring during a flight. The effects of the 14 July 2000 National Oceanic and Atmospheric Administration S3 class SEP event are examined using ground-based and satellite measurements together with coincident measurements made using a tissue equivalent proportional counter (TEPC) on board a Virgin Atlantic Airways flight from London Heathrow to Hong Kong. In this paper we present the first measurements made during a SEP event using a TEPC at flight altitudes. Our results indicate that there were no increased radiation levels detected during the flight due to the SEPs, but the measurements agreed well with the CARI-6 model calculations made using a heliocentric potential value derived immediately prior to the SEP event. In addition, a prolonged increase in the >85 MeV particle flux is observed for up to 2 days after the SEP onset by the SAMPEX spacecraft at latitudes >55°. Title: What causes solar active region loops to exist at transition region temperatures? Authors: Harra, Louise K.; Mandrini, Cristine H.; Matthews, Sarah A. Bibcode: 2004SoPh..223...57H Altcode: High-lying, dynamic loops have been observed at transition region temperatures since Skylab observations. The nature of these loops has been debated for many years with several explanations having been put forward. These include that the loops are merely cooling from hotter coronal loops, that they are produced from siphon flows, or that they are loops heated only to transition region temperatures. In this paper we will make use of combined SOHO-MDI (Michelson-Doppler Imager), SOHO-CDS (Coronal Diagnostic Spectrometer) and Yohkoh SXT (Soft X-ray Telescope) datasets in order to determine whether the appearance of transition region loops is related to small-scale flaring in the corona, and to estimate the magnetic configuration of the loops. The latter allows us to determine the direction of plasma flows in the transition region loops. We find that the appearance of the transition region loops is often related to small-scale flaring in the corona and in this case the transition region loops appear to be cooling with material draining down from the loop top. Title: Relating magnetic field strengths to hard X-ray emission in solar flares Authors: Goff, C. P.; Matthews, S. A.; van Driel-Gesztelyi, L.; Harra, L. K. Bibcode: 2004A&A...423..363G Altcode: The observation of hard X-ray (HXR) emission in solar flares provides important diagnostic information about the acceleration and subsequent transport of energetic electrons in the flare process. However, while hard X-rays are thought to be emitted from the flare footpoints through thick-target bremsstrahlung interactions, the details of the transport of accelerated electrons through the solar atmosphere still remains unclear.

Trapping of the electrons is one particular effect that is expected to occur as a result of the convergence of the magnetic field between the corona and the chromosphere. In this case the brightness of the HXR footpoints should be related to the strength of the magnetic field present and we would expect greater precipitation and higher HXR intensities at the footpoints with lower magnetic field strength. This relationship has been observed to hold in many flares (see \citealt{Sakaothesis}) but interestingly the opposite relationship, where the stronger HXR source is found at the stronger magnetic field region, has also been observed in an event studied by \citet{Asai}.

Using Data from Yohkoh's Hard X-Ray Telescope (HXT) and SOHO's Michelson Doppler Imager (MDI) we have studied the magnetic field strengths at the footpoints of a sample of 32 flares and have compared them to the hard X-ray brightness to determine whether the expected ratios are seen. We find that contrary to the expected relationship the brighter HXR footpoint is found in the region of stronger magnetic field in approximately one third of our sample of events. We discuss the implications of these results in terms of the transport mechanisms. Title: Improved data for solar flare X-ray spectral analysis Authors: Phillips, K. J. H.; Rainnie, J. A.; Harra, L. K.; Dubau, J.; Keenan, F. P.; Peacock, N. J. Bibcode: 2004A&A...416..765P Altcode: The inclusion of collisional rates for He-like Fe and Ca ions is discussed with reference to the analysis of solar flare Fe XXV and Ca XIX line emission, particularly from the Yohkoh Bragg Crystal Spectrometer (BCS). The new data are a slight improvement on calculations presently used in the BCS analysis software in that the discrepancy in the Fe XXV y and z line intensities (observed larger than predicted) is reduced. Values of electron temperature from satellite-to-resonance line ratios are slightly reduced (by up to 1 MK) for a given observed ratio. The new atomic data will be incorporated in the Yohkoh BCS databases. The data should also be of interest for the analysis of high-resolution, non-solar spectra expected from the Constellation-X and Astro-E space missions. A comparison is made of a tokamak S XV spectrum with a synthetic spectrum using atomic data in the existing software and the agreement is found to be good, so validating these data for particularly high-n satellite wavelengths close to the S XV resonance line. An error in a data file used for analyzing BCS Fe XXVI spectra is corrected, so permitting analysis of these spectra. Title: An Observational Test for Coronal Heating Models Authors: van Driel-Gesztelyi, L.; Démoulin, P.; Mandrini, C. H.; Harra, L. K.; Klimchuk, J. A. Bibcode: 2004IAUS..219..473V Altcode: 2003IAUS..219E..97V We correlate the evolution of the mean X-ray flux emission measure and temperature (Yohkoh SXT & BCS) with the magnetic flux density (SOHO/MDI) in active region NOAA 7978 from its birth throughout its decay for five solar rotations. We show that these plasma parameters together with other quantities deduced from them such as the density and the pressure follow power-law relationships with the mean magnetic flux density (bar{B}). We derive the dependence of the mean coronal heating rate on the magnetic flux density. We use the obtained scaling laws of coronal loops in thermal equilibrium to derive observational estimates of the scaling of the coronal heating with bar{B}. These results are used to test the validity of coronal heating models. We find that models invoking stochastic buildup of energy current layers and MHD turbulence are in best agreement with the observations. This narrows down the range of possible models retained by previous results obtained for individual coronal loops as well as for the global coronal emission of the Sun and cool stars. Title: On the origin of loops with transition region temperatures Authors: Mandrini, C. H.; Harra, L. K.; Matthews, S. A. Bibcode: 2004BAAA...47...32M Altcode: Very dynamic loops at transition region temperatures have been observed at coronal heights since more than 30 years. The origin of these loops is still debated and several explanations have been put forward. It has been proposed that the loops are merely cooling from hotter coronal loops, that they are produced from siphon flows, or that they are loops heated only to transition region temperatures. In this work we combine SOHO/MDI (Michelson-Doppler Imager), SOHO/CDS (Coronal Diagnostic Spectrometer) and Yohkoh/SXT (Soft X-ray Telescope) observations to determine whether the appearance of transition region loops is related to small-scale flaring in the corona, and to compute the magnetic configuration of the loops. The latter allows us to determine the direction of plasma flows in the loops. In our analyzed examples the appearance of the transition region loops is often related to small flares and, consequently, the plasma flows from the loop top to the footpoints as it cools down. Title: The Physics of the Sun Authors: Harra, Louise Bibcode: 2004spsc.book..187H Altcode: No abstract at ADS Title: Coronal emission from the active binary CC Eri Authors: Kay, H.; Matthews, S.; Harra, L.; Culhane, L. Bibcode: 2004cosp...35.1742K Altcode: 2004cosp.meet.1742K The binary star CC Eri (HD 16157) is an active star with a short orbital period of 1.56 days. It was observed for more than 35 ks with XMM-Newton in September 2003, during which it flared several times and showed a high level of X-ray variability. Preliminary analysis of the thermal structure and elemental abundances of the corona of CC Eri will be presented, along with an investigation into variation in the coronal density and opacity during flares. Simultaneous observations with the Optical Monitor, used to make a comparison between UV and X-ray emission during the flares, will also be presented. Title: An imager with added value for the Solar Orbiter mission Authors: Harra, L.; Kankelborg, C.; Thomas, R.; Fox, J.; Winter, B. Bibcode: 2004cosp...35.1120H Altcode: 2004cosp.meet.1120H Our current ways of observing the Sun with spectrometers and imagers are limited. When we use a spectrometer, we require time to build up an image. When we use a traditional imager we have no ability to measure and detect Doppler flows. These limitations will become even more restrictive on Solar Orbiter. The combination of an exciting new viewpoint of the Sun, and the best resolution of the corona ever seen, means that we require the best time cadence and velocity information that we can get. The spatial resolution expected from the imager on Solar Orbiter will reach approximately 30 km. At such a resolution in the corona, we expect to see the fundamental flux tubes, which are predicted to have high velocities. This is also the scale at which we will be able to observe basic physical processes such as magnetic reconnection occurring. We will describe a design of an imager that allows not only high quality images, but also obtains information about Doppler flows simultaneously. A prototype instrument is being flown on a NASA sounding rocket this year. The concept will be described, along with some methods of deconvolving the spectroscopic information. Title: Space Science Authors: Harra, Louise K.; Mason, Keith O. Bibcode: 2004spsc.book.....H Altcode: No abstract at ADS Title: Using Quantum Physics and Spectroscopy to Probe the Physical Universe Authors: Harra, Louise; Mason, Keith Bibcode: 2004spsc.book..251H Altcode: No abstract at ADS Title: Spectroscopic observations of coronal waves and coronal mass ejections Authors: Harra, L. Bibcode: 2004cosp...35.4417H Altcode: 2004cosp.meet.4417H I will review current spectroscopic observations of large-scale dynamic phenomena such as global coronal waves and coronal mass ejections. The aim is to determine plasma parameters such as flows. temperatures and densities to obtain a physical understanding of these phenomena. Title: Introduction Authors: Harra, Louise; Mason, Keith Bibcode: 2004spsc.book....1H Altcode: No abstract at ADS Title: Solar 'EIT Waves' - What are They? Authors: Harra, L. K.; Sterling, A. C. Bibcode: 2004IAUS..219..498H Altcode: 2003IAUS..219E..65H Using spectral data from the Coronal Diagnostic Spectrometer (CDS) instrument on the Solar and Heliospheric Observatory (SOHO) spacecraft we observe a coronal wave feature which occurred in association with a solar eruption and flare on 1998 June~13. EUV images from the Transition Region and Coronal Explorer (TRACE) satellite show that the coronal wave consists of two aspects: (1) a ``bright wave'' which shows up prominently in the TRACE difference images moves with a velocity of approximately 200km/s and is followed by a strong dimming region behind it and (2) a ``weak wave'' which is faint in the TRACE images has a velocity of about 500km/s and appears to disperse out of the bright wave. A ``high-velocity'' CDS feature however occurs after the weak wave passes which appears to correspond to ejection of cool filament-like material in TRACE images. Our observations have similarities with a numerical simulation model of coronal waves presented by Chen etal (2002) who suggests that coronal waves consist of a faster-propagating piston-driven portion and a more slowly-propagating portion due to the opening of field lines associated with an erupting filament. Title: Evidence of Flaring in a Transequatorial Loop on the Sun Authors: Harra, Louise K.; Matthews, Sarah A.; van Driel-Gesztelyi, Lidia Bibcode: 2003ApJ...598L..59H Altcode: We present evidence of flaring behavior in a transequatorial loop (TEL) that lights up in soft X-rays on 2000 July 13. The large loop structure connects NOAA Active Regions 9070/9066 in the northern hemisphere and AR 9069/9068 in the southern hemisphere. We follow the loop systems for 2 days and observe several pieces of evidence strongly suggesting flare behavior of the form seen in standard flaring in active regions. These include brightenings of the loop structure, cooling of plasma that is seen both in soft X-rays and in the transition region temperatures, morphological evidence of reconnection inflow, and blueshifts around the footpoint of the TEL suggestive of chromospheric evaporation. We present, to our knowledge for the first time, observations of TEL in the O V emission line. Title: A study of the unification of quiet-Sun transient-event phenomena Authors: Harrison, R. A.; Harra, L. K.; Brković, A.; Parnell, C. E. Bibcode: 2003A&A...409..755H Altcode: A number of small-scale, globally distributed solar transient event-types have been reported in the literature. Their potential role in fundamental processes in the solar atmosphere, such as coronal heating and wind acceleration, is under active investigation. However, the event-types, such as those known as blinkers, explosive events, EUV (extreme-UV) network and cell brightenings, network flares, heating events, nanoflares and EUV brightenings are basically classifications which are driven to a large extent by different observational techniques and different instruments rather than the identification of a clear differing physical phenomenon. We investigate the different instrumental and technique limitations and attempt to identify any unification of the reported quiet-Sun transient, small-scale phenomena. We find that once observational techniques have been considered, a number of the different classifications appear to be the same. This suggests that events known as blinkers, network and cell brightenings and EUV brightenings are the same event-type. We suggest that the term blinker be used as a generic term to describe these events. However, there appears to be little evidence that blinkers and explosive events are directly related. Furthermore, although a small percentage of blinkers and nanoflares/heating events appear to be related to one another, these events pose a number of important questions suggesting that either (i) blinkers and nanoflare/heating events are all created by the same mechanism, i.e. for some blinker events, the conditions are such that higher temperatures are found, or (ii) there are two types of event, including the ``traditional'' blinker which is effectively a transition region brightening driven by a density or filling factor enhancement, and a mini-flare-like event which reaches higher temperatures, presumably driven by reconnection. Title: Preface Authors: Harra, L. K. Bibcode: 2003AdSpR..32..883H Altcode: No abstract at ADS Title: Flare characteristics: Properties of eruptive and non-eruptive events and their associations Authors: Kay, H. R. M.; Culhane, J. L.; Harra, L. K.; Matthews, S. A. Bibcode: 2003AdSpR..32.1051K Altcode: The complex: relationship between solar flares and coronal mass ejections is investigated using a comparison of flare parameters for a total of 69 ejective and non-ejective flares. In the case of solar flares which do not show mass ejection there seems to be a clear relationship between the peak intensity and duration, with higher intensity events being of longer duration. Systematic differences in the relationship between peak temperature and intensity for the two types of events are also evident, with flares accompanied by CMEs tending to have lower peak temperatures than non-ejective events of the same intensity. Whilst there appears to be a clear relationship between the length of rise and decay phase in a flare, there are no systematic differences in the parameters between ejective and non-ejective flares. A total of eleven EIT waves were found, all of which were associated with CMEs. There is no apparent correlation between the occurrence of an EIT wave and the peak intensity or rise time of the associated flare. Title: UV spectroscopy with SOHO Authors: Harra, L. K.; Brekke, P. Bibcode: 2003AdSpR..32..965H Altcode: The UV spectroscopy from SOHO has provided new and exciting results from a wide range of phenomena observed on the Sun. Determination of plasma parameters such as velocity, density, temperatures, line widths and abundances have provided new physical insight into fundamental problems in solar physics. These include magnetic reconnection, quiet Sun coronal heating, active region dynamics, flows in solar flares, formation of the solar wind, determination of coronal mass ejection onset, characteristics of coronal waves and the twisting of magnetic structures. This paper will review these results and discuss what can be achieved with future spectroscopic instrumentation. Title: A search for X-ray variability in the open cluster NGC 2516 Authors: Ramsay, Gavin; Harra, Louise; Kay, Hilary Bibcode: 2003MNRAS.341.1388R Altcode: 2003astro.ph..2200R We present the results of a search for X-ray variability in the Galactic open cluster NGC 2516. This cluster has been observed on eight occasions using XMM-Newton, making it an excellent target for such a study. We find four sources that show significant variability, implying the detection of one significantly variable source every 25 ks. All sources exhibit spectra that can be fitted using an absorbed one- or two-temperature thermal plasma model. The brightest of these flares also show a prominent iron line near ~7.0 keV. All four sources lie near the observed main sequence of NGC 2516, suggesting that they are cluster members. We propose that at least three of the four objects are RS CVn systems. We compare the properties of the brightest flare with those of solar flares. Title: Imaging and Spectroscopic Investigations of a Solar Coronal Wave: Properties of the Wave Front and Associated Erupting Material Authors: Harra, Louise K.; Sterling, Alphonse C. Bibcode: 2003ApJ...587..429H Altcode: Using spectral data from the Coronal Diagnostic Spectrometer (CDS) instrument on the Solar and Heliospheric Observatory spacecraft, we observe a coronal wave feature (often referred to as an EIT wave) that occurred in association with a solar eruption and flare on 1998 June 13. EUV images from the Transition Region and Coronal Explorer (TRACE) satellite show that the coronal wave consists of two aspects: (1) a ``bright wave,'' which shows up prominently in the TRACE difference images, moves with a velocity of approximately 200 km s-1, and is followed by a strong dimming region behind it and (2) a ``weak wave,'' which is faint in the TRACE images, has a velocity of about 500 km s-1, and appears to disperse out of the bright wave. The weak wave passes through the CDS field of view but shows little or no line-of-sight motions in CDS spectra (velocities less than about 10 km s-1). Only a small portion of the bright wave passes the CDS field of view, with the spectral lines showing insignificant shifts. A high-velocity CDS feature, however, occurs after the weak wave passes, which appears to correspond to ejection of cool, filament-like material in TRACE images. Our observations have similarities with a numerical simulation model of coronal waves presented by Chen et al., who suggest that coronal waves consist of a faster propagating, piston-driven portion and a more slowly propagating portion due to the opening of field lines associated with an erupting filament. Title: The association of transequatorial loops in the solar corona with coronal mass ejection onset Authors: Glover, A.; Harra, L. K.; Matthews, S. A.; Foley, C. A. Bibcode: 2003A&A...400..759G Altcode: It has been shown that transequatorial loops can disappear in association with the onset of a coronal mass ejection (CME) (Khan & Hudson \cite{khan}). We extend this result by considering a larger sample of transequatorial loop systems (TLS) to investigate their associated flaring and CME activity. We find 10 of a total 18 TLS considered here to be associated with flaring and CME onset originating from a connected active region. A total 33 cases of flaring and associated CME onset are observed from these 10 systems during their lifetime. We observe the influence of this activity on the TLS in each case. In contrast to the Khan & Hudson result, we find evidence that transequatorial loop eruption leading to soft X-ray brightening equivalent in temperature to a B-class flare is equally as common as dimming in the corona. Consequently we conclude that the scenario observed by Khan & Hudson is not universal and that other types of CME-TLS association occur. It was found that for transequatorial loops that were associated with CMEs the asymmetry in longitude was larger than for those that were not associated to a CME by 10o. In addition, the extent in latitude (as a measure of the loop length) was nearly twice as large for those TLS associated with CMEs than those that were not. The asymmetry in latitude was actually on average larger for those TLS not associated with CMEs, than for those that were. This suggests that differential rotation is not a major contributor to the production of CMEs from transequatorial loops. Instead it is more likely for a CME to be produced if the loop is long, and if there is a large asymmetry in longitude. The implications of these results for CME onset prediction are discussed. Title: The Long-Term Evolution of AR 7978: The Scalings of the Coronal Plasma Parameters with the Mean Photospheric Magnetic Field Authors: van Driel-Gesztelyi, L.; Démoulin, P.; Mandrini, C. H.; Harra, L.; Klimchuk, J. A. Bibcode: 2003ApJ...586..579V Altcode: We analyze the evolution of the fluxes observed in X-rays and correlate them with the magnetic flux density in active region (AR) NOAA 7978 from its birth throughout its decay, for five solar rotations. We use Solar and Heliospheric Observatory Michelson Doppler Imager (MDI) data, together with Yohkoh Soft X-Ray Telescope (SXT) and Yohkoh Bragg Crystal Spectrometer (BCS) data, to determine the global evolution of the temperature and the emission measure of the coronal plasma at times when no significant brightenings were observed. We show that the mean X-ray flux and derived parameters, temperature and emission measure (together with other quantities deduced from them, such as the density and the pressure), of the plasma in the AR follow power-law relationships with the mean magnetic flux density (B). The exponents (b) of these power-law functions (aBb) are derived using two different statistical methods, a classical least-squares method in log-log plots and a nonparametric method, which takes into account the fact that errors in the data may not be normally distributed. Both methods give similar exponents, within error bars, for the mean temperature and for both instruments (SXT and BCS); in particular, b stays in the range [0.27, 0.31] and [0.24, 0.57] for full-resolution SXT images and BCS data, respectively. For the emission measure, the exponent b lies in the range [0.85, 1.35] and [0.45, 1.96] for SXT and BCS, respectively. The determination of such power-law relations, when combined with the results from coronal heating models, can provide us with powerful tools for determining the mechanism responsible for the existence of the high-temperature corona. Title: The Long-Term Evolution of AR 7978: Testing Coronal Heating Models Authors: Démoulin, P.; van Driel-Gesztelyi, L.; Mandrini, C. H.; Klimchuk, J. A.; Harra, L. Bibcode: 2003ApJ...586..592D Altcode: We derive the dependence of the mean coronal heating rate on the magnetic flux density. Our results are based on a previous study of the plasma parameters and the magnetic flux density (B) in the active region NOAA 7978 from its birth to its decay, throughout five solar rotations using the Solar and Heliospheric Observatory Michelson Doppler Imager, Yohkoh Soft X-Ray Telescope (SXT), and Yohkoh Bragg Crystal Spectrometer (BCS). We use the scaling laws of coronal loops in thermal equilibrium to derive four observational estimates of the scaling of the coronal heating with B (two from SXT and two from BCS observations). These results are used to test the validity of coronal heating models. We find that models based on the dissipation of stressed, current-carrying magnetic fields are in better agreement with the observations than models that attribute coronal heating to the dissipation of MHD waves injected at the base of the corona. This confirms, with smaller error bars, previous results obtained for individual coronal loops, as well as for the global coronal emission of the Sun and cool stars. Taking into account that the photospheric field is concentrated in thin magnetic flux tubes, both SXT and BCS data are in best agreement with models invoking a stochastic buildup of energy, current layers, and MHD turbulence. Title: The soft X-ray characteristics of solar flares, both with and without associated CMEs Authors: Kay, H. R. M.; Harra, L. K.; Matthews, S. A.; Culhane, J. L.; Green, L. M. Bibcode: 2003A&A...400..779K Altcode: The complex relationship between solar flares and coronal mass ejections is investigated using a comparison of flare parameters for a total of 69 ejective and non-ejective flares. In the case of solar flares which do not show mass ejection there seems to be a clear relationship between the peak intensity and duration, with higher intensity events being of longer duration. Systematic differences in the relationship between peak temperature and intensity for the two types of event are also evident, with flares associated with CMEs tending to have lower peak temperatures than non-ejective events of the same intensity. Whilst there appears to be a clear relationship between the length of rise and decay phase in a flare, there are no systematic differences in these parameters for ejective and non-ejective flares. A total of eleven ``EIT waves'' were found, all of which were associated with CMEs. There is no apparent correlation between the occurrence of an EIT wave and the peak temperature, intensity or rise time of the associated flare. Title: Evidence for a Flux Rope driven EUV wave and CME: Comparison with the Piston Shock Model Authors: Foley, C. R.; Harra, L. K.; Matthews, S. A.; Culhane, J. L.; Kitai, R. Bibcode: 2003A&A...399..749F Altcode: This paper examines the relationship between a coronal wave, filament eruption, flare and Coronal Mass Ejection (CME) which occurred on 2001, April 10th. We study the pre-flare activity which includes the eruption of a filament and a coronal wave. A large X-ray flare and a CME follow. We discuss how these phenomena are related and compare our results to recent models. These are found to be largely consistent with the numerical simulations of a flux rope driven CME as presented recently in Chen et al. (2002). Title: The occurrence of single hard x-ray sources in solar flares Authors: Goff, C. P.; Matthews, S. A.; Harra, L. K. Bibcode: 2003AdSpR..32.2483G Altcode: The 'standard' thick target flare model predicts the existence of strong hard X-ray emission at the footpointsof a flare loop. However, Yohkoh observations suggest that up to 20% of events with data available in three or more Hard X-ray Telescope (HXT) channels show only a single source. Combining datasets from Yohkoh, the Solar and Heliospheric Observatory (SOHO), and Nobeyama Radio Heliograph (NoRH), we compare the characteristics of these single source events to double source events. The objective of this study is to determine whether these represent unresolved double footpoints, asymmetric electron deposition due to magnetic mirroring effects, or a genuine departure from the 'standard' model. Title: How to test coronal heating models? Authors: Mandrini, C. H.; Démoulin, P.; van Driel-Gesztelyi, L.; Klimchuk, J. A.; Harra, L. K. Bibcode: 2003BAAA...46....5M Altcode: We have tested coronal heating models following two different approaches. In the first case, we compared the dependence of the coronal heating rate predicted by theoretical models with the observed one, deriving the scalings of parameters, such as: the density, temperature and intensity of the coronal magnetic field, with the length of magnetic field lines. To do so, we combined density and temperature measurements for 47 coronal loops with magnetic field models for 14 active regions. In the second case, we analyzed the long term evolution of an active region observed during seven rotations on the solar disk and we determined the dependence of the observed heating rate with the magnetic field density (bar{B}), after finding the scalings of plasma parameters with bar{B}. In both cases, we found that models based on the dissipation of stressed, current-carrying magnetic fields (called direct current models) are in better agreement with observations than models that attribute coronal heating to the dissipation of MHD waves injected at the base of the corona (called alternate current models). Taking into account that the photospheric field is concentrated in thin magnetic flux tubes, observations are in best agreement with models invoking a stochastic buildup of energy, current layers and MHD turbulence, within direct current models. Title: Multi-wavelength observations of the pre-cursor phase of solar flares Authors: Matthews, S. A.; Harra, L. K.; Culhane, J. L. Bibcode: 2003AdSpR..32.2553M Altcode: Observational studies of the pre-cursor phase of solar flares have shown that there are many and varied signatures that may or may not indicate the probable onset of a flare. Combining data from Yohkoh, SOHO and TRACE and more recent observations from RHESSI, SOHO and TRACE we, investigate the relationships between the different manifestations of pre-flare behaviour in two solar flares with a view to determining how they are related to the subsequent flare energy release. We find that in one case the preflare activity seems strongly related to the subsequent flare and probably represents a build-up of energy in the active region prior to flare onset. The second case we find to be less clear cut suggesting that significant further work remains to be done in order to determine which pre-flare signatures are most useful in indicating the build-up to flare onset. Title: The Solar Corona as Seen by Yohkoh Authors: Harra, L. K. Bibcode: 2002ASPC..277..277H Altcode: 2002sccx.conf..277H No abstract at ADS Title: The Coronal Emission of Photospheric Magnetic Fragments Authors: McDonald, L.; Culhane, J. L.; Matthews, S. A.; Harra, L. K. Bibcode: 2002SoPh..211..125M Altcode: This paper examines the relationship between magnetic dipoles in the photosphere and X-ray bright points (XBPs) in the corona, using an XBP special campaign dataset obtained by the Yohkoh SXT and the NSO/Kitt Peak magnetograph. We find that for the cases where a simple dipole exists in the photosphere, the condition that they are separated by a distance less than the interaction distance defined by Longcope1998 is favorable for an XBP to be observed. For the cases where the magnetic topology is more complicated due to the addition of an extra fragment, we find that the geometry of the magnetic fragments is a major factor that determines if an XBP is observed. XBPs are more likely to be formed above magnetic fragments arranged in such a way that photospheric motions giving rise to reconnection between any two fragments will also give rise to reconnection with the remaining fragment. Title: Explosive events on the Sun Authors: Harra, Louise K. Bibcode: 2002RSPTA.360.2757H Altcode: I describe two of the most dynamic and highly energetic phenomena in the Solar System-the explosive flares that can occur when plasma is confined by magnetic fields and the large-scale ejections of material known as 'coronal mass ejections'. These explosive events are poorly understood and yet occur in a variety of contexts in the Universe, ranging from planetary magnetospheres to active galactic nuclei. Understanding why flares and coronal mass ejections occur is a major goal across a wide range of space physics and astrophysics. Although explosive events from the Sun have dramatic effects on Earth, flares in other stars, for example, can be vastly more energetic and have an even more profound effect on their environment. We are now in the unprecedented position of having access to a number of space observatories dedicated to the Sun: the Yohkoh spacecraft, the Solar and Heliospheric Observatory, the Transition Region and Coronal Explorer and the Ramaty High Energy Solar Spectroscopic Imager. These cover a wide wavelength range from white light to gamma rays with both spectroscopy and imaging, and allow huge progress to be made in understanding the processes involved in such large explosions. The high-resolution data show dramatic and complex explosions of material on all spatial scales on the Sun. They have revealed that the Sun is constantly changing everywhere on its surface-something that was never imagined before. One of the mechanisms that has been proposed to account for the large energy release is magnetic reconnection. Recent observations from space increasingly support this view. This article will discuss those observations that support this model and also those that suggest different processes. The current space missions have given us an excellent insight into the actual explosive processes in the Sun. However, they have provided us with only a tantalizing glimpse of what causes the elusive trigger. Future missions such as Solar-B (the follow-on to Yohkoh), the Solar Terrestrial Relations Observatory, the Solar Dynamics Observatory and the Solar Orbiter mission will allow us to probe the trigger in a way that was not dreamt of a decade ago, by providing stereo views, measurements from Sun-grazing orbit, and much higher spatial, temporal and spectral resolution. It is an exciting time for solar physics and everything that we learn about the Sun will improve our ability to understand other magnetic phenomena in the Universe. Title: The Relationship between Duration and Intensity for Ejective and Non-Ejective Solar and Stellar Flares Authors: Magee, H. R. M.; Harra, L. K.; Matthews, S. A. Bibcode: 2002ASPC..277..533M Altcode: 2002sccx.conf..533M No abstract at ADS Title: Doppler Detection of Material Outflows from Coronal Intensity ``Dimming Regions'' During Coronal Mass Ejection Onset Authors: Sterling, A.; Harra, Louise Bibcode: 2002AAS...200.3709S Altcode: 2002BAAS...34..696S ``Coronal dimmings,'' localized regions showing a precipitous drop in EUV or X-ray emission, are a key coronal signature of the sources of Coronal Mass Ejections (CMEs). Researchers often assume that dimmings result from a depletion of coronal material (i.e., a decrease in density along the line-of-sight), even when no obvious moving structure can be detected in images. Yet, this explanation has not been unambiguously established; in principle the dimmings could, for example, be due to a dramatic change in the temperature of the emitting material instead. Here we present the most direct evidence to-date that the dimmings result from mass loss, by observing Doppler motions of material leaving the regions as they dim. Using spectral data from the Coronal Diagnostic Spectrometer (CDS) on SOHO, we observe Doppler shifts in two different events. One of these, from 1998 March 31 near 9 UT, was near the solar limb and was associated with a CME traveling in the plane of the sky, while the other event, from 1999 July 19 near 1:50 UT, was on the solar disk and was associated with an Earth-directed ``halo'' CME\@. The limb event shows Doppler signatures of ≈ 30 km s-1 in coronal (Fe xvi and Mg ix) emission lines, where the enhanced velocities coincide with the locations of coronal dimming. An ``EIT wave'' accompanies the disk event, and a dimming region behind the wave shows strong blue-shifted Doppler signatures of ≈ 100 km s-1 in the O v transition region line. These results provide strong evidence that material from the dimming regions feeds into the CMEs. This work was supported by NASA's SR&T and GI Programs, and by PPARC. Title: Changes in the solar magnetic field preceding a coronal mass ejection Authors: Harra, L. K. Bibcode: 2002JASTP..64..505H Altcode: 2002JATP...64..505H The combined observing power of the Yohkoh, SOHO and TRACE spacecraft, along with the continuing ground-based observations has proved invaluable for the detection of changes in the magnetic morphology preceding coronal mass ejections (CMEs). A wide range of activity from small scale dimmings to large scale eruptions covering half the solar disk have been observed. The relationship between flares and CMEs has also become clearer. Rather than one event causing the other it would seem that it is a global change in the magnetic field which causes both. Recently, there has been a lot of interest in the sigmoid (S-shaped) structures seen in soft X-rays. The likelihood of a CME occurring appears to increase if there is a sigmoidal structure observed. This has formed the basis of more extensive studies into predicting the time and location of a CME from the changes in behaviour of features on the solar disk. Title: The magnetic topology of a sigmoid Authors: Glover, Alexi; Ranns, Neale D. R.; Brown, Daniel S.; Harra, Louise K.; Matthews, Sarah A.; Culhane, J. Leonard Bibcode: 2002JASTP..64..497G Altcode: 2002JATP...64..497G Recent surveys of solar features have linked the ``sigmoid-to-arcade'' scenario observed in the soft X-ray corona to coronal mass ejection (CME) onset (Geophys. Res. Lett. 26 (1999) 627, Geophys. Res. Lett. 14 (1998) 2481). Further to these observations, incorporation of extreme-ultraviolet, white light and H-alpha data into such a survey (Geophys. Res. Lett. 27 (2000) 2161) has illustrated the need for a quantitative definition of the term ``sigmoid'' and further understanding of such features if they are to be used as a means by which to predict CME onset. We analyse two sample active regions in detail, each appearing both sigmoidal and eruptive in Yohkoh soft X-ray telescope (SXT) full-disk data. Both regions were observed during October 1997 and each produced a flare displaying eruptive characteristics. In each case, formation of a flare-arcade was observed by both SXT and the extreme ultraviolet imaging telescope (EIT) following the event. EUV dimming and coronal EIT waves were also observed in each case. We have studied each active region both before and after eruption using soft X-ray, EUV and H-alpha data. A linear force-free field extrapolation has also been applied as a means by which to determine the active region field deviation from potential in each case. Each active region was observed to erupt by means of a different mechanism and while both events show signatures of eruption and consequently, mass ejection, only one produced a CME large enough to be observed by the SoHO large angle spectroscopic coronagraph. The implications of these observations in terms of CME prediction are discussed. Title: Multi-wavelength observations of an X-class flare without a coronal mass ejection. Authors: Green, L. M.; Matthews, S. A.; van Driel-Gesztelyi, L.; Harra, L. K.; Culhane, J. L. Bibcode: 2002SoPh..205..325G Altcode: Developments in our knowledge of coronal mass ejections (CMEs) have shown that many of these transients occur in association with solar flares. On the occasions when there is a common occurrence of the eruption and the flare, it is most likely that the flare is of high intensity and/or long-duration (Burkepile, Hundhausen, and Webb, 1994; Munro et al., 1979; Webb and Hundhausen, 1987). A model for the relationship between the long-duration event and eruption has been developed (Carmichael, 1964; Sturrock, 1966; Hirayama, 1974; Kopp and Pneuman, 1976), but not so for the high-intensity flares and eruptions. This work investigates the magnetic topology changes that occur for a X1.2 GOES classification flare which has no associated CME. It is found that the flare is likely to result from the interaction between two pre-existing loops low in the corona, producing a confined flare. Slightly higher in the corona, a loop is observed which exhibits an outward motion as a result of the reconfiguration during reconnection. The objective of this work is to gain insight on the magnetic topology of the event which is critical in order to determine whether a high-intensity flare is likely to be related to a CME or not. Title: AstroGrid: the UK's Virtual Observatory Initiative Authors: Mann, Robert G.; Astrogrid Consortium; Lawrence, Andy; Davenhall, Clive; Mann, Bob; McMahon, Richard; Irwin, Mike; Walton, Nic; Rixon, Guy; Watson, Mike; Osborne, Julian; Page, Clive; Allan, Peter; Giaretta, David; Perry, Chris; Pike, Dave; Sherman, John; Murtagh, Fionn; Harra, Louise; Bentley, Bob; Mason, Keith; Garrington, Simon Bibcode: 2002ASPC..281....3M Altcode: 2002adass..11....3M AstroGrid is the UK's Virtual Observatory (VO) initiative. It brings together the principal astronomical data centres in the UK, and has been funded to the tune of ∼pounds 5M over the next three years, via PPARC, as part of the UK e--science programme. Its twin goals are the provision of the infrastructure and tools for the federation and exploitation of large astronomical (X-ray to radio), solar and space plasma physics datasets, and the delivery of federations of current datasets for its user communities to exploit using those tools.

Whilst AstroGrid's work will be centred on existing and future (e.g. VISTA) UK datasets, it will seek solutions to generic VO problems and will contribute to the developing international virtual observatory framework: AstroGrid is a member of the EU-funded Astrophysical Virtual Observatory project, has close links to a second EU Grid initiative, the European Grid of Solar Observations (EGSO), and will seek an active role in the development of the common standards on which the international virtual observatory will rely.

In this paper we shall primarily describe the concrete plans for AstroGrid's one-year Phase A study, which will centre on: (i) the definition of detailed science requirements through community consultation; (ii) the undertaking of a ``functionality market survey" to test the utility of existing technologies for the VO; and (iii) a pilot programme of database federations, each addressing different aspects of the general database federation problem. Further information on AstroGrid can be found at AstroGrid . Title: Non-thermal Velocities in Solar Flares [Invited] Authors: Harra, L. K. Bibcode: 2002mwoc.conf..261H Altcode: The high resolution spectroscopic information from the Bragg Crystal Spectrometer onboard Yohkoh has provided us with new and exciting information about flares and active regions. In particular, there has been much work on understanding the excess line broadening above the thermal width (known as non-thermal line broadening). We have been able to look for the first time spectroscopically at the preflare stages. The timings of the non-thermal velocity relative to the hard X-ray emission has been investigated. Non-thermal velocities have been observed to increase ten minutes before the main flares begins. Progress has been made to locate the region of dominant non-thermal velocity. This is difficult due to the lack of spatial resolution. A discussion will be made on what can be expected from the EUV Imaging Spectrometer onboard Solar B, which combines both high spatial and spectral resolution simultaneously. Title: Multi-wavelength observations of the pre-cursor phase of solar flares Authors: Matthews, S.; Harra, L.; Culhane, J. Bibcode: 2002cosp...34E1579M Altcode: 2002cosp.meetE1579M Observational studies of the pre-cursor phase of solar flares have shown that there are many and varied signatures that may or may not indicate the probable onset of a flare. Recent studies have included results showing that in some flares the non- thermal velocity of soft X-ray lines begins to rise up to 10 minutes before flare onset (Harra et al., 2001), and that UV brightenings are also seen several minutes before flare onset, at locations remote from site of the flare Hard X-ray emission (Warren &Warshall, 2001). Combining data from Yohkoh, SOHO and TRACE and more recent observations from RHESSI, SOHO and TRACE we investigate the relationships between the different manifestations of pre-flare behaviour with a view to detrmining how they affect the flare energy release process. Title: Flare characteristics: Properties of Eruptive and Non-eruptive events and their associations Authors: Culhane, J.; Magee, H.; Matthews, S.; Harra, L. Bibcode: 2002cosp...34E1676C Altcode: 2002cosp.meetE1676C We report studies of a sample of 64 solar flares - GOES class A to X. Events are classed as eruptive or non-eruptive based on whether or not accompanying CMEs were observed in SOHO LASCO or EIT data. Associations between event parameters; duratuion, intensity, temperature and emission measure and presence or absence of a related CME are discussed. Intensity and duration are considered for a sample of stellar flares and the relationship with solar flares is examined. For a subset of the solar flare sample, the significance of the hard X-ray spectral slope and the association with coronal waves is assessed. Title: Single source hard X-ray sources and the standard flare model Authors: Goff, C.; Matthews, S.; Harra, L. Bibcode: 2002cosp...34E1082G Altcode: 2002cosp.meetE1082G The 'standard' flare model predicts the existence of strong Hard X-ray emission at the footpoints of the flare loop. However, Yohkoh observations suggest that a third of events show instead only a single source. Combining datasets which include observations from Yohkoh, RHESSI, SOHO, TRACE and Nobeyama we compare the characteristics of these single source events to a group of double source events with the aim of determining whether these sources represent unresolved double footpoints, asymmetric electron deposition due to magnetic mirroring effects, or a genuine departure from the 'standard' model. Title: Anatomy of a Flare and Coronal Mass Ejection Authors: Foley, C. R.; Harra, L. K.; Culhane, J. L.; Mason, K. O.; Hori, K.; Matthews, S. A.; Iles, R. H. A. Bibcode: 2002mwoc.conf..253F Altcode: In this paper we present the observations of a flare, CME and their interaction obtained with the SOHO, Trace, and Yohkoh spacecraft. More specifically we show evidence for wave-like motions in the Trace 171 observations, of comparable speed to those usually inferred from EIT observations and thus termed `EIT waves'. We find that these waves commence at the same time at which a prominence is observed to rise within the active region and signifies the start of a gradual coronal mass ejection. The prominence is observed with the Coronal Diagnostic Spectrometer, on SOHO, with red and blueshifts which can only be reconciled if the structure is rotating close to the plane of the image with an angle of ~ 72o, to line of sight. During, the impulsive phase of the flare the prominence and CME is observed to accelerate from 190km/s to 900km/s. Title: Flare Temperature from FE XXV and CA XIX: Improved Atomic Data Authors: Phillips, K. J. H.; Rainnie, J. A.; Harra, L. K.; Dubau, J.; Keenan, F. P. Bibcode: 2002mwoc.conf..293P Altcode: For several years flare temperatures and emission measures have been derived from comparison of observed Yohkoh BCS spectra with theoretical spectra derived from atomic parameters based on distorted wave approximation. In the case of Fe XXV and Ca XIX spectra, the main lines used in the determination are dielectronic satellite lines (j or k as appropriate) and the resonance line w. More accurate close-coupling calculations from the R-matrix procedure have been available in unpublished form, and in this work these new atomic data were substituted for the distorted wave data. The intensities of the Fe XXV and Ca XIX lines w, x, y, and z are affected -- all are increased. However, the differences from the previously used atomic data are very slight. We estimate that for a given j/w ratio in Fe XXV, for instance, the temperature estimated from the new atomic data will be about 1MK smaller than from the existing data in the standard Yohkoh software at temperatures of around 20MK. Smaller differences are expected for Ca XIX at typical temperatures of 14MK. The increase in the Fe XXV y and z line intensities tends to reduce a well-known discrepancy in these lines (more evident in the much better resolved SMM BCS spectra) but not by a sufficient amount to explain the discrepancy. Title: Ultraviolet spectroscopy with SOHO Authors: Harra, L. Bibcode: 2002cosp...34E1466H Altcode: 2002cosp.meetE1466H The UV spectroscopy available from SOHO has provided new and exciting results for a wide range of phenomena observed on the Sun. Determination of plasma parameters such as velocity, density, temperatures and abundances have provided new physical insight into fundamental problems in solar physics. These include magnetic reconnection, emerging flux, quiet Sun , active region heating, the characteristics of coronal waves, flows in solar flares, formation of the solar wind, determination of coronal mass ejection onset and twisting of magnetic structures. This paper will review these results, and discuss what can be achieved with future spectroscopic instrumentation. Title: The timing of non-thermal soft X-ray emission line broadenings in solar flares Authors: Ranns, N. D. R.; Harra, L. K.; Matthews, S. A.; Culhane, J. L. Bibcode: 2001A&A...379..616R Altcode: We study 59 solar limb flares using the Bragg Crystal Spectrometer (BCS) on Yohkoh and the Burst and Transient Source Experiment (BATSE) to investigate the relative timings between the Hard X-Ray (HXR) emission and the observed non-thermal broadenings of X-ray emission lines (Vnt). We show that the duration of the HXR flux rise to maximum emission affects the relative timing of the main Vnt peak with respect to the main HXR peak. In ~20% of the flares studied, secondary peaks in Vnt are observed. These are always associated with a strong HXR pulse and usually occur after the associated HXR pulse. There are also flares that show a relationship between the decay times of Vnt and HXR flux. These results are conducive to a causal relationship between the HXR flux and Vnt. We divided the sample of flares into two classes, gradual rise and impulsive rise, depending on the shape of the HXR lightcurve up to maximum emission. We show that the Vnt behaviour differs in the two classes. The implications are discussed with a view to understanding the mechanism of Vnt generation. Title: Material Outflows from Coronal Intensity ``Dimming Regions'' during Coronal Mass Ejection Onset Authors: Harra, Louise K.; Sterling, Alphonse C. Bibcode: 2001ApJ...561L.215H Altcode: One signature of expulsion of coronal mass ejections (CMEs) from the solar corona is the appearance of transient intensity dimmings in coronal images. These dimmings have generally been assumed to be due to discharge of CME material from the corona, and thus the ``dimming regions'' are thought of as an important signature of the sources of CMEs. We present spectral observations of two dimming regions at the time of expulsion of CMEs, using the Coronal Diagnostic Spectrometer (CDS) on the SOHO satellite. One of the dimming regions is at the solar limb and associated with a CME traveling in the plane of the sky, while the other region is on the solar disk and associated with an Earth-directed ``halo'' CME. From the limb event, we see Doppler signatures of ~30 km s-1 in coronal (Fe XVI and Mg IX) emission lines, where the enhanced velocities coincide with the locations of coronal dimming. This provides direct evidence that the dimmings are associated with outflowing material. We also see larger (~100 km s-1) Doppler velocities in transition region (O V and He I) emission lines, which are likely to be associated with motions of a prominence and loops at transition region temperatures. An ``EIT wave'' accompanies the disk event, and a dimming region behind the wave shows strong blueshifted Doppler signatures of ~100 km s-1 in O V, suggesting that material from the dimming regions behind the wave may be feeding the CME. Title: Eruption of a Flux Rope on the Disk of the Sun: Evidence for the Coronal Mass Ejection Trigger? Authors: Foley, Carl R.; Harra, Louise K.; Culhane, J. Leonard; Mason, Keith O. Bibcode: 2001ApJ...560L..91F Altcode: The first evidence of acceleration of a flux rope from the disk of the Sun using the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) is presented. A distinct blueshifted emission component (-480 km s-1) was observed by the EUV spectrometer on SOHO at the start of the impulsive phase of an X2.3 flare. There is a halo coronal mass ejection associated with this event. Based on a sequence of velocity measurements, we determine the acceleration of the erupting material. These results are supported by simultaneous EUV imaging data from the Transition Region and Coronal Explorer spacecraft, which shows the projected motion of the flux rope. The CDS spectra reveal an initial rapid acceleration phase (3.5 km s-2), followed by a transition to a more gradual acceleration (0.68 km s-2). This may indicate energy input via explosive reconnection. Title: Long term evolution of a non-active region sigmoid and its CME activity Authors: Glover, A.; Harra, L. K.; Matthews, S. A.; Hori, K.; Culhane, J. L. Bibcode: 2001A&A...378..239G Altcode: Recent studies have considered sigmoidal features in the Solar corona to possess a high probability of eruption. Unlike these studies which have focussed only on active region sigmoids, the present work centres on a large area which developed S-like morphology unconfined by a single active region. The S-like feature formed near the central meridian on 8th May 2000 and was observed to erupt, with an associated CME, twice over a period of 3 days. We observe considerable CME and flaring activity in two previous rotations, consistent with the observation of active regions and emerging flux. We illustrate sigmoid formation through the appearance of highly sheared soft X-ray loops overlying an extended filament channel. This arises from the gradual diffusion of flux associated with a large, dispersing active region over the period of three solar rotations. This scenario is indicative of shear build-up within the region over several rotations. The observed CMEs act to remove helicity from the highly sheared sigmoidal feature, finally producing an approximately potential filament channel on 10th May 2000. Title: Magnetic field configurations and the likelihood of coronal mass ejections Authors: Culhane, J. L.; Glover, A.; Green, L. M.; Harra, L. K.; Matthews, S. A.; Hori, K. Bibcode: 2001ESASP.493..193C Altcode: 2001sefs.work..193C No abstract at ADS Title: Velocity observations of an active region during the onset phase of a coronal mass ejection Authors: Harra, Louise K.; Sterling, Alphonse C. Bibcode: 2001ESASP.493..237H Altcode: 2001sefs.work..237H No abstract at ADS Title: Coronal heating in the Sun and late-type stars Authors: Harra, L. K.; Culhane, J. L. Bibcode: 2001Obs...121..217H Altcode: No abstract at ADS Title: Energetics of an Active Region Observed from Helium-Like Sulphur Lines Authors: Watanabe, Tetsuya; Sterling, Alphonse C.; Hudson, Hugh S.; Harra, Louise K. Bibcode: 2001SoPh..201...71W Altcode: We report temperature diagnostics derived from helium-like ions of sulphur for an active region NOAA 7978 obtained with Bragg Crystal Spectrometer (BCS) on board the Yohkoh satellite. For the same region we estimate conductive flux downward to the chromosphere by the Coronal Diagnostic Spectrometer (CDS) on board the Solar and Heliospheric Observatory (SOHO) satellite. This region appeared as a region of soft X-ray enhancement in May 1996, underwent a period of enhanced activity coinciding with flux emergence between 6 July and 12 July, and then continued to exist in a nearly flareless state for several solar rotations until November 1996. Energy balance of the non-flaring active region is basically consistent with a model of an arcade of coronal loops having an average loop-top temperature of 4×106 K. Energy from flare activity during a period of flux emergence is comparable to the energy requirements of the non-flaring active region. However, the non-flaring energy is roughly constant for the subsequent solar rotations following the birth of the active region even after the flare activity essentially subsided. Energy partition between flare activity and steady active-region heating thus varies significantly over the lifetime of the active region, and active-region emission cannot always be identified with flaring. Title: Coronal mass ejections and their association to active region flaring. Authors: Green, L. M.; Harra, L. K.; Matthews, S. A.; Culhane, J. L. Bibcode: 2001SoPh..200..189G Altcode: Since the discovery of coronal mass ejections (CMEs), flaring has been thought to be associated in some way with the ejection in either cause or effect. When CMEs were first discovered in the 1970s it was suggested that they were powered by solar flares (e.g., Dryer, 1982). Research since then (Harrison, 1986) has indicated that there is an associated flare that occurs shortly after the CME. To investigate this further, and making no assumption that a particular flare is causally connected to the CME, flaring activity in nine active regions that show one or more CME signatures has been studied for several hours before and after CME launch. Although the initiation of the CME may occur on size scales larger than the active region itself, definite changes are seen in the flaring activity which may be related to the ejection. This work indicates that the energy released from the active region magnetic field via flaring is greater prior to the CME launch than after. Title: Radio and X ray Observations of a Limb Flare during the Max Millennium Campaign Authors: Lee, J.; Gallagher, P. T.; Gary, D. E.; Harra, L. K. Bibcode: 2001AGUSM..SP51A03L Altcode: A powerful (GOES Class M9.8), limb flare was observed on 1999 August 20 above AR 8673 during the second Max Millennium campaign. Due to its location on the limb as well as its strength, the flare observation provides an ideal case of studying vertical structure of electron acceleration and its transport. The hard X ray images from Yohkoh/HXT along with EUV images from SoHO/EIT show an impulsive, compact double brightening in the lower atmosphere and a hypothesis of footpoint emission from a compact loop seems likely. In contrast, microwave visibilities obtained using the Owens Valley Solar Array (OVSA) suggest a region of high energy electrons high in the corona (2x 105 km), requiring large loops that can act as a good trap of electrons. The duration of radio emission is also much extended compared with the hard X ray emission. We present this set of observations as a good example of the trap-plus-precipitation hypothesis, and derive numbers of electrons emitting the microwaves and hard X rays, respectively, as a measure for the trap vs. precipitation. The derived time evolution of electron numbers in energy space is not compatible with a simple hypothesis of energy-independent acceleration solely under Coulomb collisions, but instead requires an acceleration or transport process that is highly energy-dependent. Title: Coronal heating Authors: Harra, Louise Bibcode: 2001A&G....42b..18H Altcode: Louise Harra presents a summary of a meeting at which a wealth of new sources of data - Yohkoh, SOHO, TRACE, XMM-Newton and Chandra - is bringing new insights to studies of solar and stellar coronal heating. Title: Nonthermal Velocity Evolution in the Precursor Phase of a Solar Flare Authors: Harra, L. K.; Matthews, S. A.; Culhane, J. L. Bibcode: 2001ApJ...549L.245H Altcode: We present observations of two solar flares occurring in Active Region 7590 on 1993 October 3 using data from the Yohkoh spacecraft. The hard X-ray bursts from the two flares occurred within an 18 minute interval, with the soft X-ray emission having a shorter separation of ~5 minutes. Both flares occurred within one Yohkoh orbit, and hence we have continuous coverage of the soft X-ray line broadening at the peak of the first flare, reducing to the active region level of 33.5 km s-1 in S XV (66.1 km s-1 in Ca XIX) and then increasing to the peak in the second flare. The rise above the active region background level begins 11 minutes before the start of the second flare as defined by the start of the hard X-ray emission. During this extended rise time of Vnt, there is no increase in the light curves or the electron temperature. We suggest that this increase is an indicator of turbulent changes in the active region prior to the flare that are related to the flare trigger mechanism. Title: An Observational Test for Solar Atmospheric Heating Authors: van Driel-Gesztelyi, L.; Démoulin, P.; Ireland, J.; Thompson, B.; Fludra, A.; Oláh, K.; Kövári, Zs.; Harra, L. K.; Mandrini, C. H.; Bocchialini, K.; Orlando, S. Bibcode: 2001IAUS..203..514V Altcode: We study the evolution of the emissivity and heating correlated with magnetic observables of an active region from its birth throughout its decay during seven solar rotations (July-Dec. 1996). Taking one "snapshot" per g:wq: Command not found. time of flares, we analyse multi-wavelength and multi-instrument data obtained from SOHO (MDI, EIT, CDS and SUMER), Yohkoh (SXT), GOES, SOLSTICE and 10.7 cm radio data from DRAO, Canada. We utilise our results to test the validity of coronal heating models. We find that models which are based on the dissipation of stressed, current-carrying magnetic fields are in better agreement with the observations than the models which attribute coronal heating to the dissipation of MHD waves. Title: Properties of EUV and X-ray emission in solar active regions Authors: Matthews, S. A.; Klimchuk, J. A.; Harra, L. K. Bibcode: 2001A&A...365..186M Altcode: Using observations from the Coronal Diagnostic Spectrometer (CDS) on SoHO and the Soft X-ray Telescope (SXT) on Yohkoh we investigate how the spatial properties of active region emission observed in the EUV and X-ray range varies with temperature. We examine the contrast per unit area of the EUV emission from a number of active regions, and employ correlation techniques and Fourier methods with which we obtain the two dimensional power spectrum of the intensity distribution for a number of images in emission lines formed at different temperatures. Integrating this over polar angle we find isotropic power-law behaviour at all temperatures in a number of topologically different active regions, with a tendency for flatter spectra at lower temperatures. The existence of power-law spectra indicates that there is no preferred length scale within the regions, at least not a resolvable one, while flatter spectra at lower temperatures indicate that the structures are relatively smaller in this temperature range, possibly providing support for the idea of a multi-component transition region (TR). Implications for various heating models are discussed. Title: Quiet Sun Brightenings - Cell and Network Behaviour (CD-ROM Directory: contribs/harra) Authors: Harra, L.; Gallagher, T. P.; Phillips, J. J. H. Bibcode: 2001ASPC..223..674H Altcode: 2001csss...11..674H No abstract at ADS Title: Location of the source of soft X-ray non-thermal line broadenings in a solar flare Authors: Ranns, N. D. R.; Matthews, S. A.; Harra, L. K.; Culhane, J. L. Bibcode: 2000A&A...364..859R Altcode: We determine the location of the source of the non-thermal Soft X-ray line broadenings in an M1.7 two-ribbon solar flare using multi-wavelength observations. Using a combination of the Yohkoh Soft X-ray Telescope (SXT), Hard X-ray Telescope (HXT), Bragg Crystal Spectrometer (BCS) and the Transition Region and Coronal Explorer (TRACE), we find the source of the non-thermal broadenings, at their peak value, to be located in and above the SXR flare loops, not at the flare loop footpoints. After eliminating the footpoints as a potential source we discuss the likelihood that the source of non-thermally broadened emission lines is either evaporating chromospheric plasma or plasma above the Soft X-ray flare loop that is associated with the flare energy release. Title: Characteristics of quiet Sun cell and network brightenings Authors: Harra, L. K.; Gallagher, P. T.; Phillips, K. J. H. Bibcode: 2000A&A...362..371H Altcode: Extreme ultraviolet observations of the quiet Sun are made with the Coronal Diagnostic Spectrometer (cds) on board the Solar and Heliospheric Observatory (soho). It has been previously noted that frequent transition region brightenings occur in both the bright network and dark cell regions. Analysing 1125 events, we determined the characteristics of the brightenings in the cell and network regions which include the duration, energy, and intensity increase above the background. Network brightenings are found to be larger than cell events occurring with a mean duration of 150 s and releasing an average of 1026.9 ergs per event. Cell brightenings, on the other hand, last for an average of 96 s and release 1025.8 ergs per event. It has also been found that the distribution of energy is a power-law which is different in the cell (gamma =2.5) and network (gamma =1.5) regions. When the entire quiet Sun region is analysed the value of gamma is 1.7. The number of events per cds pixel is approximately the same, and a histogram of the ratio ([peak value - background]/background) shows similar values for both the cell and network. It is important to analyse the cell and network regions separately in the context of coronal heating by such small flare-like events. Title: The Energy Supply to X-ray Bright Points Authors: McDonald, L.; Culhane, J. L.; Harra, L. K.; Matthews, S. A. Bibcode: 2000SoPh..196..137M Altcode: X-ray bright points (XBPs) are usually assumed to be isolated structures in the solar atmosphere that are powered exclusively by magnetic reconnection. We analyse a large XBP that does not satisfy this assumption. The XBP is observed to be connected to an active region approximately 280 000 km away by a magnetic loop. We find that the soft X-ray intensity and thermal energy of the XBP are very sensitive to the existence of the magnetic loop. Both the intensity and energy decrease significantly at the times when the loop disappears, indicating that the loop is a medium for energy transfer from the active region to the XBP. We deduce that the mechanism for the energy transfer is most likely to be Alfvén or fast-mode magnetoacoustic waves created by photospheric motions in the active region. These waves can dissipate energy at the density gradient between the XBP and the loop via phase mixing or resonant absorption. Title: Emerging flux as a driver for homologous flares Authors: Ranns, N. D. R.; Harra, L. K.; Matthews, S. A.; Culhane, J. L. Bibcode: 2000A&A...360.1163R Altcode: We present multi-wavelength observations of 2 M-class solar flares observed by SoHO and Yohkoh, which appear to be homologous. By examination of the flare loop morphology and footpoints we propose a schematic reconnection scenario of a two loop interaction in a quadrupolar magnetic configuration, for both flares (Machado ?; Mandrini ?). After the first flare, the combination of chance emergence of new flux at an opportune location and a subsequent flare, of the type described by Heyvaerts et al. (?), form a new quadrupolar configuration in which the second flare occurred. Therefore though the two M-class flares are homologous by definition, they appear to conform to a scenario in which the preflare conditions are reformed after the first flare by emerging flux, rather than models which involve the continual shearing of a single magnetic structure. Title: The onset and association of CMEs with sigmoidal active regions Authors: Glover, Alexi; Ranns, Neale D. R.; Harra, Louise K.; Culhane, J. Leonard Bibcode: 2000GeoRL..27.2161G Altcode: Previous studies of active regions characterised by Soft X-ray S or inverse-S morphology [Canfield et al., 1999], have found these regions to possess a higher probability of eruption. In such cases, CME launch has been inferred using X-ray proxies to indicate eruption. Active regions observed during 1997, previously categorised as both sigmoidal and eruptive [Canfield, 1999], have been selected for further study, incorporating SoHO-LASCO, SoHO-EIT and ground based H-alpha data. Our results allow re-classification into three main categories; sigmoidal, non-sigmoidal and active regions appearing sigmoidal due to the projection of many loops. Although the reduced dataset size prevents a statistical measure of significance, we note that regions comprising a single S (or inverse-S) shaped structure are more frequently associated with a CME than those classed as non-sigmoidal. This motivates the study of a larger dataset and highlights the need for a quantitative observational definition of the term “sigmoid”. Title: Solar activity studies through coronal X-ray observations Authors: Harra, Louise Bibcode: 2000RSPTA.358..641H Altcode: The solar corona consists of high-temperature plasma that is contained by a wide range of magnetic field structures. The cyclic behaviour of solar activity results in continuing evolution of these structures. This evolution can be well studied by observing the X-ray and extreme ultraviolet (EUV) emission from the hot plasma which delineates the magnetic field in the corona. In this review, the X-ray images obtained from the Yohkoh mission over more than half a solar cycle and the information they provide about coronal evolution will be discussed. A variety of short-term transient brightenings observed by Yohkoh, and at EUV wavelengths by the SOHO mission, will be described and their relevance for coronal heating evaluated. Yohkoh observations have advanced our understanding of solar flares. These important results will be summarized and discussed. Finally, the current view of the nature of coronal mass ejections as deduced by Yohkoh and SOHO is presented. Title: Active region dynamics Authors: Harra, L. K.; Matthews, S. A.; Hara, H.; Ichimoto, K. Bibcode: 2000ssls.work..109H Altcode: It has been frequently observed that in solar active regions the measured line widths are larger than those based on thermal equilibrium widths. This excess width (characterised as non-thermal velocity, Vnt) has been proposed as a signature of the heating mechanism. The behaviour of the Vnt at coronal temperatures has not produced consistent results with values ranging from 0 to 100 km/s. We investigate this problem by using joint observations from Norikura Solar Observatory, Japan and the Coronal Diagnostic Spectrometer (CDS) on SOHO. We find that values of Vnt range between 10-20 km/s. We analyse the dynamical bahaviour of different temperature loops and find that for loops with log Te < 5.8, the variability ∝Te0.39. This is comparable to the dependence of non-thermal velocity on temperature which we have determined to be Vnt ∝ Te0.35. This suggests that the excess line broadening is caused by highly dynamical behaviour in the transition region for active regions. These results have significant implications for potential heating mechanisms and these are discussed. Title: The spatial distribution of EUV emission in active regions Authors: Matthews, S. A.; Klimchuk, J. A.; Harra, L. K. Bibcode: 2000ssls.work...53M Altcode: The full version of this paper will be published elsewhere. We give here only an extended abstract. Title: The Determination of Electron Densities in the Solar Atmosphere from the 1718.56 Angstrom /1486.51 Angstrom Emission-Line Ratio in N IV Authors: Keenan, F. P.; Harra, L. K.; Doschek, G. A.; Cook, J. W. Bibcode: 1994ApJ...432..806K Altcode: The theoretical electron density sensitive emission-line ratio R = I(1718.56 a)/I(1486.51 A) in N IV is presented for a range of Ne(approximately equals 1010 - 1012/cu cm) applicable to higher density solar plasmas, such as active regions. A comparison of these calculations with the observed values of R of several solar features obtained with the Naval Research Laboratory's S082B spectrograph on board Skylab reveals general agreement between theory and observation at pointings just above the limb, where line blends with N IV 1718.56 A should be insignificant, which provides experimental support for the accuracy of the line ratio calculations. Title: Coronal Electron Density Diagnostic from Fe XII Authors: Cook, J. W.; Keenan, F. P.; Harra, L. K.; Tayal, S. S. Bibcode: 1994ApJ...429..924C Altcode: We present observations of the forbidden coronal lines Fe XII 1242 A and 1349 A from active regions and from two flares, obtained by the SO82B slit spectrograph onboard Skylab. The line intensity ratio R = I(1242 A)/I(1349 A) is sensitive to electron density. We have calculated this ratio using recent atomic data, and obtained coronal electron densities at T = 1.5 x 106 K for our observations. We find a range in Ne of (0.5 to 7.2) x 109/cm-3 for active regions, which is in good agreement with previous results from other diagnostic ratios in this temperature range, and of approximately (0.9 to 12) x 109/cm-3 (or higher) for flares, which is generally low compared to previous flare results. The flare values employ particularly weak 1349 A observations and may not be reliable. From an observation of an active region just inside the solar limb, giving the best coverage in our data of both line profiles, we find a line width (FWHM) for both lines of 0.20 A, which corresponds to a nonthermal velocity of 18 km/sec. Title: Calculated He-Like Argon Line Intensities and Comparison with Solar Flare Spectra from the FCS Instrument on the Solar Maximum Mission Authors: Harra, L. K.; Phillips, K. J. H.; Keenan, F. P.; Zarro, D. M.; Wilson, M. Bibcode: 1994emsp.conf...77H Altcode: No abstract at ADS Title: Helium-like Argon Line Emission in Solar Flares Authors: Phillips, K. J. H.; Harra, L. K.; Keenan, F. P.; Zarro, D. M.; Wilson, M. Bibcode: 1993ApJ...419..426P Altcode: Theoretical X-ray spectra of Ar XVII lines and Ar XVI satellites at ∼4 Å, derived from R-matrix code and other calculations, are compared with solar-flare observations obtained with the SMM Flat Crystal Spectrometer. There is good agreement between the observed line features and those in the theoretical spectra, and the comparison leads to best-fit values of electron temperature for the observed solar flares. We present wavelengths for the Ar XVII and some Ar XVI lines, measured from the observed spectra, which have better precision than previous values. In addition, the coronal Ar/S abundance is determined from the relative intensities of Ar XVII lines to those of nearby S XV transitions, and the value of this ratio is discussed in the light of previous work. Title: Electron density diagnostics applicable to IUE spectra of gaseous nebulae. Authors: Keenan, F. P.; Feibelman, W. A.; Harra, L. K.; Conlon, E. S.; Aggarwal, K. M. Bibcode: 1993uxrs.conf..341K Altcode: 1993uxsa.conf..341K Observed values of the emission line ratios R = I(3s2 1S - 3s3p 3P2)/ I(3s2 1S - 3s3p 3P1) = I(2660 Å)/I(2669 Å) in Al II, R1 = I(2s2 1S - 2s2p 3P2)/ I(2s2 1S - 2s2p 3P1) = I(1907 Å)/I(1909 Å) in C III, and R2 = I(3s2 1S - 3s3p 3P2)/ I(3s2 1S - 3s3p 3P1) = I(1883 Å)/I(1892 Å) in Si III, measured from high resolution spectra obtained with the International Ultraviolet Explorer (IUE) satellite, are presented for several planetary nebulae and symbiotic stars. Electron densities deduced from these ratios in conjunction with new theoretical R, R1 and R2 diagnostics (which are significantly different from those calculated by previous authors), are found to be compatible, and are also in good agreement with those derived from line ratios in other species. This provides observational support for the accuracy of the atomic data adopted in the line ratio calculations. Title: Spectral studies of high temperature plasmas Authors: Harra, Louise Kim Bibcode: 1993PhDT.......252H Altcode: No abstract at ADS Title: Ar XVII X-ray lines emitted by solar flares. Authors: Phillips, K. J. H.; Keenan, F. P.; Harra, L. K.; McCann, S. M. Bibcode: 1993uxrs.conf..579P Altcode: 1993uxsa.conf..579P Recent calculations of electron impact excitation rates in helium-like argon (Ar XVII) have been used to derive emission line intensities for the resonance (1s2 1S0 - 1s2p 1P1), intercombination (1s2 1S0 - 1s2p 3P1,2) and forbidden (1s2 1S0 - 1s2s 3S1) lines that appear in the X-ray region (≍4 Å). These have been combined with calculations of nearby dielectronic satellites of Ar XVI to synthesize spectra that can be compared with observations. The synthetic spectra are sensitive to electron temperature Te but not electron density unless extremely large (>1014cm-3). Comparisons have been made using observations taken during solar flares with the Flat Crystal Spectrometer (part of the X-ray Polychromator) on Solar Maximum Mission and with spectra from the Alcator tokamak. The observed spectra show good agreement with the theoretical spectra, and demonstrate the feasibility of using Ar XVII line ratios for determining Te. Title: The determination of solar coronal electron temperatures from Mg XI emission lines in SMM-FCS spectra of flares and active regions. Authors: Harra, L. K.; Phillips, K. J. H.; Keenan, F. P.; Conlon, E. S.; Kingston, A. E. Bibcode: 1993uxrs.conf..551H Altcode: 1993uxsa.conf..551H Recent atomic physics calculations for Mg XI are used to derive the electron temperature sensitive emission line ratios G = [I(1s2 1S - 1s2s 3S) + I(1s2 1S - 1s2p 3P1,2)]/ I(1s2 1S - 1s2p 1P), R1 = I(1s2 1S - 1s3p 1P)/ I(1s2 1S - 1s2p 1P), and R2 = I(1s2 1S - 1s4p 1P)/ I(1s2 1S - 1s2p 1P), which are found to be significantly different from earlier results. Values of Te deduced from G, R1 and R2 ratios measured from solar flare and active region spectra obtained with the Flat Crystal Spectrometer (FCS) on board the Solar Maximum Mission (SMM) satellite are consistent. This provides support both for the validity of the theoretical G, R1 and R2 diagnostics, and for the FCS calibration curve in the wavelength region covering the Mg XI transitions, 7.472-9.314 Å. Title: EUV lines of Mg IX as ne-diagnostics for high density flares. Authors: Harra, L. K.; Keenan, F. P.; Widing, K. G.; Conlon, E. S. Bibcode: 1993uxrs.conf..320H Altcode: 1993uxsa.conf..320H Theoretical Mg IX electron density sensitive emission line ratios, derived using electron impact excitation rates interpolated from accurate R-matrix calculations, are presented for R1 = I(443.97 Å)/I(368.07 Å), R2 = I(439.17 Å)/I(368.07 Å), R3 = I(443.40 Å)/I(368.07 Å) and R4 = I(441.20 Å)/I(368.07 Å). A comparison of these with observational data for solar flares, obtained with the Naval Research Laboratory's S082A spectrograph on board Skylab, reveals excellent agreement between theory and observation for R1 and R2, which confirms the usefulness of these ratios as Ne-diagnostics for solar flares, as well as providing experimental support for the accuracy of the atomic data adopted in the line ratio calculations. However the observed values of both R3 and R4 generally imply unrealistically high electron densities, which is probably due to blending in the 443.40 and 441.20 Å lines, possibly with Ar IV 443.44 Å and Mg VI/Mg VII 441.22 Å, respectively. Title: Energy levels and oscillator strengths for transitions in helium-like Fe XXV and Ni XXVII. Authors: Harra, L. K.; Boone, A. W.; Norrington, P. H.; Keenan, F. P.; Kingston, A. E. Bibcode: 1993uxrs.conf..122H Altcode: 1993uxsa.conf..122H Configuration interaction (CI) wavefunctions are used to calculate energy levels and oscillator strengths for all significant electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1) and magnetic quadrupole (M2) transitions among the 1s2, 1s2l and 1s3l states of He-like Fe XXV and Ni XXVII. Accurate wavefunctions are also obtained using the fully relativistic MCDF method and similarly employed to calculate these same energy levels and oscillator strenths. Derived energy levels are compared to each other and with previous results, and indicate that the MCDF method gives data which are closer to the experimental energies. The calculated CI and MCDF A-values are found to be in good agreement, but differ significantly in some cases from these and previous authors. Title: X-Ray Emission-Line Ratios in MG XI as Electron Temperature Diagnostics for Solar Flares and Active Regions Authors: Keenan, F. P.; Phillips, K. J. H.; Harra, L. K.; Conlon, E. S.; Kingston, A. E. Bibcode: 1992ApJ...393..815K Altcode: Electron temperature-sensitive emission-line ratios are derived via electron impact excitation rates for transitions in helium-like Mg XI, calculated with the R-matrix code. These ratios are found to be significantly different from earlier diagnostic calculations of Keenan et al. (1984, 1991), and lead to electron temperature estimates up to a factor of about 1.6 larger. Values of Te deduced from R1 and R2 ratios measured from solar flare and active region spectra obtained with the FCS on board the SMM satellite are consistent and in good agreement with temperatures estimated from the observed G ratios for these solar features. This provides support both for the validity of the theoretical R1 and R2 diagnostics, and for the FCS calibration curve in the wavelength region covering the Mg XI transitions 7.472-9.314 A. Title: AI II as an electron density diagnostic for the upper chromosphere/lower transition region in late-type stars. Authors: Doyle, J. G.; Keenan, F. P.; Harra, L. K.; Aggarwal, K. M.; Tayal, S. S. Bibcode: 1992A&A...261..285D Altcode: The ratio of the Al II resonance line 3s2 1S-3sp 1P1 at 1670 A to the inter-system line 3s2 1S-3s3p 3P1 at 2669 A is a useful electron density diagnostic for N(e) greater than 10 exp 10/cu cm. However, it is also sensitive to the adopted electron temperature, and, in fact, should be a useful electron temperature diagnostic when Ne is not greater than 10 exp 9/cu cm. In particular, we present observational data for the RS CVn star II Peg and show that this ratio implies an electron pressure substantially less than that implied from other diagnostic line ratios but in good agreement with the pressure derived from the C III 1176/C III 1908 ratio. We suggest additional observational and theoretical work that may be required. Title: NE V Line Ratios in the EUV Spectra of Solar Flares Authors: Keenan, F. P.; Conlon, E. S.; Harra, L. K.; Aggarwal, K. M.; Widing, K. G. Bibcode: 1992ApJ...389..440K Altcode: Theoretical line ratios involving 2s22p2-2s2p3 transitions in Ne V between 359 and 572 A are presented. A comparison of these with solar-flare observational data from the spectrograph on board Skylab reveals excellent agreement between theory and experiment, with discrepancies that average only 8 percent. This provides experimental support for the accuracy of the atomic data adopted in the line-ratio calculations, and in addition resolves discrepancies between theory and observations previously found for this species. The potential usefulness of the Ne V line ratios as electron temperature diagnostics for the solar transition region is briefly discussed. Title: MG IX Line Ratios in the Sun Authors: Keenan, F. P.; Conlon, E. S.; Harra, L. K.; Widing, K. G. Bibcode: 1992ApJ...386..371K Altcode: Attention is given to theoretical Mg IX electron density sensitive emission-line ratios derived using electron impact excitation rates interpolated from accurate R-matrix calculations, which are presented for R1 = I(443.97 A)/I(368.07 A), R2 = I(439.17 A)/I(368.07 A), R3 = I(368.07 A)/I(443.07 A), and R4 = I(441.20 A)/I(368.07 A). A comparison of these with observational data for solar flares on board Skylab reveals excellent agreement between theory and observation for R1 and R2, which confirms the usefulness of these ratios as Ne-diagnostics for solar flares, as well as providing experimental support for the accuracy of the atomic data adopted in the line ratio calculations. The observed values of both R3 and R4 generally imply unrealistically high electron densities, which is argued to be due to blending in the 443.40- and 441.20-A lines, probably with Ar IV 443.44 A and Mg VI/Mg VII 441.22 A, respectively. Title: AL II Emission-Line Strengths in Low-Density Astrophysical Plasmas Authors: Keenan, F. P.; Harra, L. K.; Aggarwal, K. M.; Feibelman, W. A. Bibcode: 1992ApJ...385..375K Altcode: Theoretical values of the emission-line ratio R are derived for the transitions 3s2 1S-3s3p 3P2 and 3s2 1S-3s3p 3P1 in Al II, at 2660 and 2669 A, respectively. These ratios are compared with IUE observations of the planetary nebula NGC 7027 and the symbiotic star RR Tel, to illustrate the usefulness of the R as an electron density diagnostics. A value of R = 0.72 was deduced for NGC 7027, which implies log Ne = 4.2 for Te = 14,000 K. This is consistent with densities deduced earlier for this planetary nebula. Title: C IV Line Ratios in the Sun Authors: Keenan, F. P.; Conlon, E. S.; Harra, L. K.; Burke, V. M.; Widing, K. G. Bibcode: 1992ApJ...385..381K Altcode: Theoretical electron temperature-sensitive emission-line ratios are calculated with R-matrix analysis of electron-impact excitation rates for transitions in C IV. Two of the emission-line ratios are found to agree with observational data on the sun taken with a slitless spectrograph aboard Skylab, and the two remaining lines have inaccuracies that can be attributed to blending of the 312.43 A line. The agreement between the observational and analytical data lends credence to the accuracy of the atomic data used in the analysis. Title: X-ray emission-line ratios in He-like ions as electron-temperature diagnostics for solar flares and active regions (abstract) Authors: Harra, L. K.; Phillips, K. J. H.; Keenan, F. P.; Bromage, B. J. I.; McCann, S. M. Bibcode: 1992sccw.conf..144H Altcode: No abstract at ADS Title: Improved Line Ratio Calculations Involving Delta N = 1 (2--3) Transitions in O V and a Reanalysis of SKYLAB Observations of Solar Flares Authors: Keenan, F. P.; Dufton, P. L.; Harra, L. K.; Conlon, E. S.; Berrington, K. A.; Kingston, A. E.; Widing, K. G. Bibcode: 1991ApJ...382..349K Altcode: R-matrix calculations of electron-impact-excitation rates in O V are used to rederive theoretical electron-density diagnostic emission-line ratios involving transitions between the n = 2 and 3 levels, which includes lines at 192.80, 192.90, 215.10, 215.25, 220.35, and 248.46 A. A comparison of these diagnostics with observational data for two solar flares obtained with the spectrograph on board Skylab reveals better agreement between theory and observation than was found previously. This provides experimental support for the improved accuracy of the atomic data employed in the present analysis.