Some studies on Hα-flares and microwave bursts in relation to sunspot magnetic configurations

Abstract

Sunspot associated Hα-flares and microwave bursts occurring during the period 1972 to 1974 have been examined in relation to the magnetic strength and configurations of the sunspots and sunspot groups (abbreviated as ‘spots’). Important results obtained are: (i) percentage occurrences of flares exceeds those of microwave bursts up to a magnetic field strength of 2000 G while the reverse is true for higher field strength of ‘spots’, (ii) flare productivity (average number of flares per spot) and also burst productivity are comparatively higher in the case of ‘βγ’ and ‘δ’ types of spots than in the case of other types of spots, (iii) the above productivities are predominantly high when magnetic configuration of ‘spots’ changes during their life time, and (iv) ‘impulsive’ type of microwave bursts are more associated with ‘spots’ having ‘changing type’ of magnetic configuration.