Polarization Reversal of Solar Microwave Bursts

Abstract

HIGH resolution observations of solar microwave bursts were reported recently by Tanaka and Énomé¹. Using interferometric methods, they resolved the microwave bursts into two components, R₁ and R₂ which were well correlated with distinct sunspots in one-dimensional spatial position. The interferometric measurements were at one frequency, but the polarization characteristics of each source were separately estimated at several other frequencies¹. In Table 1 we have reproduced the sense of circular polarization of each source and the maximum flux density of the combined emission for the January 18, 1969, event. Each source had an opposite sense of polarization and, as a function of frequency, the sense of circular polarization reversed, separately, for both sources. The polarization centre of one source showed a definite movement¹ with an estimated velocity of about 2,500 km s⁻¹.