Some Studies on Solar Radio Bursts & SIDs in Relation to Distinctive Visual Features of H_ɑ-Flares

Abstract

Solar H_ɑ-Flares reported under a scheme of classification based on their distinctive visual features have been examined for a period of about eight years. Flare-radio burst and flare-sudden ionospheric disturbances (SIDs) association and also the peak flux spectra of the associated bursts have been studied. The following important results are obtained, viz. (i) D-type of flares, compared to other types, are the most predominant and appear to concentrate more towards the disk limb; (ii) flare-burst association is frequency dependent and has the highest and the lowest values for H- and D-types of flares respectively; (iii) peak flux spectra of each type of flares reveal that the flux density shows a definite increase in the decimetric region; (iv) decametric type III bursts generally do not coincide with these types of flares; if they do, they accompany microwave and decimetre wave bursts in 30% and 43% cases respectively and (v) flare-SID association is highest for F-type and lowest for D-type of flares.