Semi-empirical Model of the White Light Flare on September 19, 1979

The intensities of the continuum emission and the Call K line of the white light flare with 3B importance on September 19, 1979 are measured and analyzed. Their variations with time are given. It is indicated that the continuum emission of this flare appeared in the early impulsive phase and lasted for about 5～6 min, with the time of maximum intensity 2～3 min earlier than that for the microwave radio burst. Based on the non-LTE theory, a semi-emplrical model at a time with the continuum emission being relatively intensive is presented. The resuhs show that the temperature in the flare photosphere is increased by 150～250 K, and that the continuum emission is produced mainly by the negative hydrogen ion. Finally, some discussions about the heating mechanism are also presented, implying that the heating energy may come from the lower atmosphere itself.