A SOLAR-FLARE IN THE FE-I-5324 LINE ON 24 JUNE, 1993

A solar flare with both H beta and FeI 5324 emissions was observed in AR 7529 (S13, E65) on 24 June, 1993 at the Bejing Astronomical Observa tory. Our calculations show that the Fe I 5324 emission region of the flare was located in the low photosphere at a height of about 180 km a bove tau(5000) = 1, which is lower than many previous studies of white -light flares. To study a Fe I 5324 flare, which represents a kind of extreme case in solar flares, would be useful for clarifying some argu ments in the researches of white-light flares as well as for understan ding the mechanism of solar flares. The synthetic analyses from vairou s features of the hare lead to the following possible exciting mechani sm of the FeI 5324 flare: owing to the flow of energetic electrons fro m the corona and probably also the thermal conduction downward into th e lower atmosphere, a condensation with a temperature higher than that below it was formed near the transition region. Then the low photosph ere was heated through backwarming. The Fer 5324 flare occurred as an indicator of the excitation in the low photosphere.