1. Paolo Grigis 2. Alec Engell 3. Keiji Yosimura 4. Masumi Shimojo 5. Antonia Savcheva 6. Mark Weber 7. Aki Takeda 8. Noriyuki Narukage 9. Ryouhei Kano 10. Paola Testa 11. Piet Martens 12. Kathy Reeves 13. Dana Longcope 14. Adam Kobelski 15. Lewis Fox ============================================== "Thermal evolution of solar flare plasma" Paolo C. Grigis, SAO Solar flares release large amounts of energy that quickly and violently heats active region plasma. We study the thermal evolution of flares jointly observed by SDO/AIA and XRT by comparing lightcurves and images in different channels of AIA and XRT. In particular, we investigate the relative timing of the rise and decay phases of the lightcurves seen by XRT, AIA, GOES and RHESSI to reconstruct the heating and cooling behavior of the flare plasma as it evolves. ----------------------------------------------------- "XRT-SphinX" Alec Engell Using the X-Ray Telescope (XRT), Solar photometer in X-rays (SphinX), and Michelson Doppler Imager (MDI), we present a study of 114 flares occurring in AR 11024 from July 3-7, 2009.Ê By comparing the integrated lightcurves from XRTÕs field of view (FOV) and the temperatures derived from SphinX spectra inÊwe clearly see that they are observing the same flaring events.Ê AR 11024 is the only AR on disk throughout the study so the contribution to the SphinX measurements are the quiet Sun, AR emission, and flaring emission.ÊÊThe flare study of AR 11024 reveals that with the different stages of magnetic flux emergence there are different stages of flare activity. ÊFlare morphologies and flare temperatures are also analyzed. -------------------------------------------------------- "Cancelling magnetic features and X-ray Brightenings in Emerging Flux Regions" Keiji Yoshimura, MSU Magnetic structure of isolated emerging flux region(EFR) is rather simple compared to that of a general active region. We may be able to observe "simplified" activities in an EFR, especially in its early phase. We study the activities in X-ray images around isolated EFRs, focusing on the relationship between photospheric magnetic field and X-ray brightenings in the corona. I will summarize what we have found and discuss the relationship between photospheric magnetic cancellation and X-ray bright points. ------------------------------------------------------------------ "The evolution of the magnetic field distribution investigated based on the prominence activities" Masumi Shimojo (Nobeyama Solar Radio Observatory/NAOJ) Although Nobeyama Radioheliograph (NoRH) was built to study solar flares based on the microwave emission from non-thermal electrons, NoRH is one of the best instruments for the monitoring observations of prominences, because NoRH can observe the sun on cloudy/rainy days. In order to utilize the advantages of NoRH, we developed the automatic detection program of the prominence activities (Shimojo et al. 2006) and applied the program to the NoRH data from the middle of 1992 to the end of 2009 (about 17.5 years). As a result, we detected 871 events and made the butterfly diagram from the position of the prominence activities. Though it is said that the duration of Cycle 23 is over 12 years, we found from the diagram that the magnetic distribution of the solar northern hemisphere is changing with 11 years cycle during Cycle 23 and 24. If the evolution of the magnetic distribution of the northern hemisphere does not change in several years, the polarity inversion in the north pole would occur between the late of 2011 and the early of 2012. On the other hand, in the southern hemisphere, the new magnetic pattern of cycle 24 does not appear and the polarity inversion in the south pole might delay from the northern one. In the talk, we discuss also the polar observations by Hinode. -------------------------------------------------------- "Application of Quasi-Separatrix Layer Maps to Understanding the Structure and Evolution of Sigmoids" Antonia Savcheva, E. DeLuca, A. Van Ballegooijen We present some preliminary work in attempt to utilize Quasi-Separatrix Layer (QSL) maps for understanding the structure and evolution of sigmoids. We show sample QSL maps calculated at different heights above the photosphere and different times over the evolution of the quiescent sigmoid from February, 2007, observed with Hinode/XRT. The QSL maps use already existing static MHD models of the sigmoid, based on the flux rope insertion method. We give a short overview of the method used to set-up these maps. By comparing current distributions and the squashing factors at different height and cross sections over the sigmoid location we suggest the use of QSLs as tracers of surface and/or volumetric currents. We look at the distribution, structure, and concentration of QSLs in combination with the size and location of bald patches at different stages of the sigmoid development. We attempt to use this analysis to help us discriminate between the main scenarios for the formation and X-ray appearance of the S-like structure - flux emergence (or cancellation) and twisting foot point motions. This method may possibly shed some light on the pre-eruption configuration and eruption mechanism in sigmoids as well. -------------------------------------------------------- "Recalculating Yohkoh/SXT Temperature Response Functions" Aki Takeda and the YLA project team (MSU and LMSAL) Yohkoh Legacy data Archive (YLA) is one of the first group of the Resident Archives (RAs) selected for funding for NASA's Virtual Observatories for Heliophysics Data program. YLA provides the best corrected data set from Yohkoh satellite with user-friendly web interface and e-mail based individual user support, via http://solar.physics.montana.edu/ylegacy. As part of efforts to improve the quality and usability of the YLA products, we recently renewed the SXT response functions, from the traditional calculation based on Mewe et al.,1985, to those calculated with the most recent Chianti atomic database and software (version 6.01). The new response functions and filter ratio curves are summarized at http://solar.physics.montana.edu/ylegacy/documents/sxt_response/sxt_new_response.html. The new calculation shows SXT is more sensitivity to the hotter plasma around 10MK, and thus the peak temperature of the thin analysis filters (Al.1, AlMg, and Mg) increases from ~5MK to ~10MK. The filter ratio temperatures derived from our thickest filter pair (Be/Al12) increase by up to 50 percent for the cases formerly yielded over 10MK. --------------------------------------------------------------- "Property of solar coronal structures based on temperature and emission measure derived with Hinode/X-Ray Telescope" Noriyuki Narukage (NAOJ) Coronal observations in X-rays show the sun has many features in the corona which have a wide temperature range from less than 1 MK to more than 10 MK. The X-ray telescope (XRT) on board the Hinode satellite has an ability to observe the almost of whole coronal plasma. Using the data set observed with this telescope, the coronal temperature and emission measure can be derived across the whole sun. We find that coronal structures are classified with temperature and emission measure (EM), i.e., each coronal structure have each typical temperature and EM. On the basis of this result, we also derive the typical heating flux in the solar corona. --------------------------------------------------------------- "Multi-thermal structures above a polar region observed with XRT and EIS" R. Kano (NAOJ) It is important to derive spatial structures of coronal temperature, because they give us the information where coronal heating is taking place. Although Kano et al. (2008, PASJ) applied the XRT filter-ratio method to a polar coronal region, the temperature structure derived with the filter-ratio method probably misleads us to a wrong conclusion about heating locations, if observed features have multi-thermal plasma. Therefore, we revisited the temperature structure above a polar region by using the coordinated eclipse observation between XRT and EIS on January 26 in 2009. The differential emission measure (DEM) distributions derived with the EIS raster-scan data at the altitudes of 10", 50" and 100" clearly show multi-thermal structures at any altitudes. The vertical variation of the DEM is almost consistent with the hydrostatic pressure gradient at each temperature. On the other hand, the horizontal variation of the XRT filter-ratio temperature shows two types of solar plumes: "cool" plumes having lower (filter-ratio) temperature than surroundings and "warm" plumes having higher. They seem to be embedded in a diffuse inter-plume plasma component. These results suggest a multilevel structure of the polar corona region. From a microscopic viewpoint, it consists of fine-scale vertical magnetic threads that are isothermal along magnetic fields but different temperatures in different threads. From a macroscopic viewpoint, it consists of three components: "cool" plumes, "warm" plumes and inter-plume plasma. "Cool" and "warm" plumes may be a bundle of threads with different proportions of "cooler" and "warmer" threads. The isothermal structure along the magnetic fields in a thread supports the idea that coronal plasma is heated near the footpoint ("footpoint heating"). -------------------------------------------------------- "Constraining plasma temperature distribution of active regions from simultaneous XRT and EIS data" Paola Testa, Fabio Reale, Enrico Landi, Ed DeLuca We investigate thermal properties of coronal plasma in non-flaring active regions using simultaneous Hinode XRT and EIS observations which provide complementary diagnostics for the X-ray emitting plasma. The use of multi-filter XRT datasets together with EIS spectra allows us to accurately constrain the thermal structure of the active region plasma, and to investigate instruments cross-calibration. We discuss limits of the plasma diagnostics, systematic discrepancies and their likely sources. -------------------------------------------------------- "Automated Feature Recognition for Hinode" Petrus C Martens (MSU) and the SDO Feature Finding Team The SDO Feature Finding Team is developing a suite of 16 automated feature finding software that will automatically, and in most cases in near-real-time, detect, analyze, and catalog metadata on features such as flares, coronal dimmings, flux emergence and evolution, sigmoids, active regions, coronal holes, etc. The set of modules is rounded out by a trainable feature detection module that in interaction with the user can be honed to extract newly discovered phenomena and features not covered by the other modules (e.g. anemones) from its catalog of image texture parameters. Our modules are being and in some cases have been adjusted to analyze data from other solar space missions, including Hinode. ÊI will show some results of automated sigmoid detection in Hinode/XRT data, and discuss in some detail the workings of the trainable feature detection module. -------------------------------------------------------- "Flare Emissions and Energy Partition in a Simulated Solar Eruption" Kathy Reeves, Jon Linker, Zoran Mikic and Terry Forbes We model a CME and associated flare using a 2.5D numerical MHD code that includes coronal heating, thermal conduction and radiative cooling in the energy equation. We examine the simulated emissions due to this modeled eruption and find that we can reproduce cusp-shaped flare loops observed in XRT filters as well as and bright post-flare loops in the EUV wavelengths. The simulation also predicts that the structures surrounding the current sheet should be visible in XRT observations. Additionally, we find that as the eruption progresses, density is swept away from the low corona, providing an explanation for coronal dimming during eruptions. We calculate the energy budget for the simulated CME and find reasonable agreement with the energy partitioning in observed solar eruptions. -------------------------------------------------------- "Conduction Fronts in Petschek Reconnection" Dana Longcope, Montana State University In models of fast magnetic reconnection flux transfer occurs within a small portion of a current sheet triggering stored magnetic energy to be thermalized by shocks. Except in cases of purely anti-parallel reconnection, the energy conversion occurs in two steps via two distinct shocks. A rotational discontinuity converts magnetic energy to bulk kinetic energy forming, at least in steady state models, an outflow jet. Within the outflow jet slow magnetosonic shocks convert a portion of the kinetic energy to heat. Since bulk kinetic energy is carried mostly by ions, the electrons are heated slowly, through inefficient collisions, and achieve their final temperature away from the shocks. Heat transferred to the electrons is conducted upstream to form conduction fronts ahead of the slow shocks. Except in cases very close to the anti-parallel limit this conduction fronts do not extend beyond the rotational discontinuities and are therefore confined within the outflow jet. Because the electrons are heated gradually their heat flux is never near the saturation limit. On the other hand, the ion viscosity briefly achieves a level at (or beyond) the limit of valid fluid treatment. ----------------------------------------------------- "Photometric Uncertainty in HINODE/XRT" Adam Kobelski As XRT continues to extend its lifetime, it is expected that more photometric studies of high energy activities on the sun will be undertaken. ÊThis will require a more thorough analysis of the uncertainties that exist within the observations. ÊIn this study, I will give a brief overview of some of the sources of the uncertainties, and present results pertaining to the uncertainties induced by the on-board JPEG compression. -------------------------------------------------------- "Correcting XRT Contamination Spots by Flat-fielding" J. Lewis Fox, David McKenzie, Charles C. Kankelborg Beginning in mid-2007, the XRT images are marred by dark spots due to beads of congealed contaminant. ÊWhile programs are available for improving the cosmetic appearance of the images, no method has yet been demonstrated for a quantitative correction. ÊWe have employed a flat-fielding method developed for MSU's MOSES sounding rocket payload, in an attempt to restore capabilities for quantitative photometry in the affected pixels. ÊInitial results are encouraging; characterization of the uncertainties in the photometric correction are ongoing. We will report on the degree to which this flat-fielding attempt has been successful. While the method shows promise there remain outstanding issues, notably spectral variability of the contaminant spots within individual filter bands. --------------------------------------------------------