Energetic electron heating and chromospheric evaporation during a well-observed compact flare

Abstract

A previous analysis of chromospheric evaporation in the solar flare of May 7, 1980, in which it was shown that the chromospheric evaporation can account for the thermal X-ray plasma of the flare, is extended. The way the H-alpha profile should respond to thick-target nonthermal electron heating is discussed using previous theoretical modelling. It is shown that broad Stark wings are the theoretically expected response above moderately high values of the input nonthermal electron energy flux. The observed spatial and temporal behavior of H-alpha profiles and hard X-rays during the impulsive phase is exmined, and it is concluded that broad H-alpha wings are closely related observationally to hard X-rays. Finally, it is shown that the observed width of impulsive-phase H-alpha wings supports the thick-target nonthermal electron heating model.