<論文>「たんせい4号」による太陽フレアX線輝線スペクトルの観測

概要

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Observations of soft X-ray line emissions of highly ionized iron and calcium have been made by Bragg spectrometer (LiF) aboard Tansei 4 satellite. Two wave length regions: 1.8-2.0A and 3.1-3.25A are measured simultaneously with spectral resolution of 0.005 A. A combination of high sensitivity and high time resolution measurements enabled to detect initial heating phase of flares. Rapid shift of the peak intensity in the iron line spectrun from 1,885A region to 1.865A region together with K_α emmission has been observed at the very initial phase of impulsive flares in coincidence with hard X-ray and microwave bursts. This indicates that individual heating occurs in less than 10 seconds simultaneously with the production of high energy electrons. Rapid increase of turbulence during the heating phase has been found from line broademing of FeXXV resonance line. It is also found that temperature and emission measure of soft X-ray emitting plasma increase and decrease simultaneously for small flares contrary to previous results by soft X-ray continuum emission. Plasma compression has been suggested for the heating mechanism of flares.
宇宙航空研究開発機構の論文