Nobeyama one-day symposium on solar physics

Date: 2002 July 12 (Fri.)
Location : Nobeyama Solar Radio Observatory
Subject : Solar physics

• "RHESSI images" (J. Sato)
• "RHESSI and NoRH" (M. Shimojo)
• "Supra-arcade Downflows in the 21 April 2002 X Flare" (D. McKenzie)
  The 21 April 2002 X-class solar flare included supra-arcade downflows of the type described by McKenzie and Hudson (1999). The downflows, clearly imaged by TRACE, crossed the position of the SUMER slit. A comparison of the TRACE and SUMER data concerning the supra-arcade downflows will be presented.
• "Footpoint behavior" (H. Hudson)
• "Direct Precipitation? Trapping?" (S. Masuda)
• "MHD Simulation of a Solar Flare" (T. Yokoyama)
• "High-beta disruption scenario of solar flares" (K. Shibasaki)
  A new solar flare scenario is proposed based on the high-beta plasma disruption. Recent observations of flare dynamics (movies) by TRACE, NoRH and RHESSI will be interpreted by the new scenario.
• "Evolution of flare ribbons and energy release" (A. Asai)
• "Two-component interpretation of solar & stellar coronal plasma differential emission measure (DEM) distributions" (T. Watanabe)
  Yohkoh has successfully observed high temperature component of solar coronal plasmas, while increasing number of EUV observations has determined stellar coronal DEMs. Comparing these DEM figures rather qualitatively, it is found that the lower temperature DEM hump is constantly situated at around 2 million degree, while the location of higher temperature hump varies with the level of stellar activity, and that the creation of these higher temperature components might be closely related to flare-like transient activity via magnetic reconnection process.
• "A Decade-Long Study of the Quiet Solar Corona" (L. Acton)
• "Emission Measure Distribution for An Active Region using YOHKOH/Soft X-ray Telescope" (M. Shimojo)
  The active region NOAA6919 was observed by YOHKOH/Soft X-ray Telescope on 18 November, 1999. Hara et al. (1992) reported the temperature analysis of the active region and revealed that the hot plasma (5 sim 6 MK) exist in not only bright loops but also faint parts of the active region. We expand their study using CHIANTI spectrum database (Dere, et al., 2000) and derive the Differential Emission Measure (DEM) distributions of the active region. In this paper, we show the preliminary results of the DEM analysis using YOHKOH/SXT. The Withbroe-Sylwester method (Withbroe, 1975, Sylwester et al., 1980) is used to obtain the DEMs for the active region which was observed SXT using five different X-ray filters. The temperature range of the DEMs is from 2MK to 20MK. The DEMs of the quiet loops in the center of the active region show the power-law distribution with an index of 4 sim 5. We also examine the time evolutions of DEMs at the brightening loops and found that the index of the DEM distributions slightly decreases during the loop brightening.
• " " (A. Sterling)
• "SOHO-CDS observations of Plasmoids (poster)" (C. Foley)
  We present observations of plasmoids and rising flare cusps observed with SOHO-CDS, in. These are all associated with Coronal Mass Ejections, which most probably represent the reconnection of coronal field lines as the CME is disconnected from the sun. We examine the evolution of observed post cme structures in the context of the Standard Flare model.

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