Flares on the Sun: Selected Results from HINOTORI

Katsuo Tanaka
1983 International Astronomical Union Colloquium  
ABSTRACTThe X-ray observations of solar flares by Japanese astronomy satellite Hinotori (ASTRO-A) are reviewed. Detailed results from the X-ray telescope and the soft X-ray spectrometers are given. The hard X-ray images in the 17-40 keV range show a wide variety of source structures. Examples of compact single source, stationary coronal source, and double sources are presented. High resolution spectra in the range 1.7-2.0A indicate strong turbulence and blue-shifted components in the beginning
more » ... s in the beginning of flares. From the FeXXV and FeXXVI spectra two kinds of thermal plasma are shown to appear. The cooler component of Te=15-20xl06K, which increases in the impulsive phase of the hard X-ray burst, is suggested to be produced by the dissipation of the electron beams. The hotter component of Te=30-50xl06K and Ne=1011-1012increases towards the flare maximum. This component is also responsible for emitting 17-40keV continuum, and emitted from a very compact source. The results are discussed in comparison with flare loop models. It is shown that evolutionary changes in the loop density realize various source structures in the hard X-ray under the unitary electron beam hypothesis.
doi:10.1017/s0252921100096226 fatcat:m5kfz3272ra2vecnebizeuxyp4