Soft X-ray and microwave observations of hot regions in solar flares

✍ Scribed by H. S. Hudson; K. Ohki

• Publisher: Springer
• Year: 1972
• Tongue: English
• Weight: 696 KB
• Volume: 23
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00153899

✦ Synopsis

Hot regions in solar flares produce X-radiation and microwaves by thermal processes. Recent X-ray data make it possible to specify the temperature and emission measure of the soft X-ray source, by using, for instance, a combination of the 1-8 A (peak response at about 2 keV) and the 0.5-3 ]k (peak response at about 5 keV) broad-band photometers. The temperatures and emission measures thus derived satisfactorily explain the radio fluxes, within systematic errors of about a factor of 3. Comparison of 15 events with differing parameters shows that a hot solar flare region has an approximately isothermal temperature distribution. The time evolution of the correlation in a single event shows that the hot material originates in the chromosphere, rather than the corona. The density must lie between 101~ and 2 • 1011 cm-L For an Importance 1 flare, this implies a stored energy of roughly 2 • 1030 --1029 ergs. A refinement of the data will enable us to choose between conductive and radiative cooling models.