Implications of polarization properties of type III solar radio bursts at decametric wavelengths

Abstract

The present work analyzes some Faraday rotation measurements of type III bursts carried out by means of a two-bandwidth time-sharing polarimeter at 35 MHz. It was found that type III bursts at 35 MHz had axial ratios at the source ranging mostly between -0.15 and plus 0.20, indicating that the bursts were highly elliptically polarized, with degree of polarization varying between 20 and 100 per cent. The present results indicated that the observed value of the Faraday rotation at 35 MHz is at least two orders of magnitude less than what is theoretically expected. This low value for the Faraday rotation is discussed from the viewpoint of being possibly due to mode coupling in the earth's ionosphere or in the solar corona.