Coronal heating and the X-ray and microwave emission from M-dwarf flare stars
A current-dissipation model for coronal heating is used to study the conditions required for simultaneously generating the X-ray and microwave emission observed from M-dwarf flare stars. The hot X-ray emitting plasma is produced through Joule heating in the current sheets. The microwave emission may be either thermal cyclotron or gyrosynchrotron emission (Linsky and Gary 1983). If the current drift speed is on the order of the ion sound speed, in addition to heating, significant electron acceleration will also occur. It is shown that, under conditions required to heat the coronal plasma, the drift speed is likely to be greater than the sound speed and enough energetic electrons are accelerated to explain the microwave emission as gyrosynchrotron radiation from nonthermal electrons. The results are compared to the hard X-ray microflares observed on the sun.
KeywordsCurrent Sheet Coronal Plasma Microwave Emission Coronal Heating Drift Speed
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