DIAGNOSTICS OF NONTHERMAL PROCESSES IN CHROMOSPHERIC FLARES .1. H-ALPHA AND CAII K-LINE PROFILES OF AN ATMOSPHERE BOMBARDED BY HECTA KEV ELECTRONS

The significance of non-thermal excitation and ionization of hydrogen and CaII, by an electron beam, on the line profiles of Halpha and Call K line has been investigated. Non-LTE Halpha and CaII K line profiles have been calculated for the temperature distributions of semi-empirical flares models F1 and F2 (Machado et al. 1980). For reasonable values of the beam energy flux and power index, the hydrogen lines are greatly strengthened and broadened, and an obvious central reversal appears. The effects are weaker for the CaII K line. These effects can be used to diagnose electron beam bombardment during a solar flare, especially at its early phase. Any semi-empirical flare model that does not take into account non-thermal effects overestimates the heating of the solar atmosphere.