Solar Physics

, Volume 23, Issue 1, pp 155–168 | Cite as

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

  • H. S. Hudson
  • K. Ohki
Article
Received:

Abstract

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 Å (peak response at about 2 keV) and the 0.5–3 Å (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 1010 and 2 × 1011 cm−3. For an Importance 1 flare, this implies a stored energy of roughly 2 x 1030-1029 ergs. A refinement of the data will enable us to choose between conductive and radiative cooling models.

Keywords

Microwave Flare Thermal Process Solar Flare Emission Measure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© D. Reidel Publishing Company 1972

Authors and Affiliations

  • H. S. Hudson
    • 1
  • K. Ohki
    • 1
  1. 1.Tokyo Astronomical ObservatoryTokyoJapan

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