A Spectacular Coronal Mass Ejection Event and Associated Phenomena

Based on the data taken from S.G.D.and relevant simultaneous observations of solar radio bursts,gamma-ray emissions and geophysical effects on June 15,1991 the relationships among these phenomena are discussed in this paper. In the observation records of Yunnan Observatory, a spike-Ⅲ burst happened on the metric waveband at 063730UT.The type-Ⅲ burst took place within the waveband of 230-250MHz and showed an evident frequency-drift at both positive and negative directions.Within 230-250MHz the drift rate was-46MHz/s and on the waveband beyond 250MHz the drift was positive and the rate was 65MHz/s.Regarding to the Tarnstrom and Philips classification,the drift rate was moderate.There were millisecond spikes around the waveband of 271-281MHz and they became a type-Ⅲ burst when developing into the waveband beyond 282MHz.The spikes and type-Ⅲ burst corresponded with an X12/3B grade flare that started form 0633UT,maximum at 0831UT,ended at 1117UT and was one of the 6 great flares happened in the AR6659.The metric spikes-Ⅲ burst happened in the rise phase of the flare. Through the analyses it is considered that proton events and GLE events occurred on June 15 in 1991,which were the geophysic responses caused by CME(V≥750km/s).Simultaneous observation of the bursts at the centimetric and decimetric wavelengths can obtain the U-shape spectrum of speak fluxes,which is still one of the effective tools for predicting proton events and its production mechanism can be explained by using the acceleration of the direct current field parallel to the magnetic field in the electric current sheet formed in the process of the production of spray prominences.However,the process in which electrons are accelerated up to the high energy state remains to be explained.The whole event of June 15 1991, form the coronal matter ejection (or the spray prominences in active regions) to the production of various geophysic effects,has explained and verified.