Radio Evidence of a Coronal Instability Before the Onset of a Solar Flare (9 June 1968)

Abstract

The outburst and storm of more than four hours’ duration that accompanied the importance 2 flare beginning at 0 h 25 m U.T. on 9 June 1968 were observed at 80 MHz with the Culgoora radioheliograph. More than 10 4 heliograms in both senses of circular polarization were recorded at one-second intervals both as cathode-ray-tube photographs and as digital characters on magnetic tape. It is the purpose of this preliminary account to summarize these observations and bring attention to a new phenomenon observed before the start of the flare.