RATAN-600 Observations of Unusual Inversion of Polarization in Sunspot Associated Microwave Sources

Abstract

We have discovered unusual inversion of circular polarization in both components of an active region. We have observed the region for six consecutive days in May 96 using the RATAN-600 radio telescope with high polarization accuracy up to 0.5 %. The observations were taken in the range of 1.7 to 30 cm. At short wavelengths the circular polarization scans revealed a bipolar structure, expected since the magnetic field is bipolar. However, for all six days and while the region was moving from the center of the disk to the west limb, the circular polarization dropped practically to zero at 14.5 cm and at longer wavelengths the sense of the polarization was reversed.