A Correlation between the Optical and Radio Aspects of a Class 3 Flare

Abstract

It is shown that variations in the H α intensity of a bright dot which appeared over the umbra of a sunspot during the Class 3 flare of 1960 November 10, were synchronous with variations in the level of the accompanying 20 cm radio emission. No such correlation existed between the characteristics of the radio emission and the behaviour of other H α regions within the flare although it is possible that minor contributions to the radio emission were made when certain of the H α regions expanded over minor spots. An examination of all the available single frequency records on centimetre, decimetre and metre wavelengths reveals that those radio bursts accompanying variations in the intensity of the H α spot were Type IV events and the ionospheric record indicates that these changes in the visible and radio radiation were accompanied by simultaneous variations in the flare X-ray radiation.