Return current losses in pulse beam heating of the solar atmosphere

Abstract

The influence of return current losses on pulse beam heating of the solar atmosphere is studied using a 1 D-hybrid code. While heating of the coronal plasma by the penetrating electron beam is obtained, as expected, strong return current losses of beam electrons at the resistivity jump in the transition region are also found. The electron beam energy is deposited at greater heights in the solar atmosphere than in the case of pure collisional losses. At the starting time of the flare, due to a strong return current heating, a very steep transition region is formed where upwards and downwards plasma flows are generated. However, this state has a transitory character. The atmosphere is heated and a channel of hot, low resistivity plasma is formed, by which the following electron beams can penetrate more easily to deep chromospheric levels, where they are then thermalized.