Some Features of Manifestations of Coronal Holes in Microwave Emission
Grechnev, Victor V.; Krissinel, Boris B.; Kuznetsova, Svetlana M.; Maksimov, Vladimir P.; Prosovetsky, Dmitry V.; Stepanov, Alexandr P.; Shishko, Ludmila F.
Russia, Japan
Abstract
Using observational data from the SSRT, we have investigated the behavior of four mid- and low-latitude coronal holes. The coronal holes under study appeared as regions of decreased emission intensity relative to the quiet Sun level totally or partially coincident with holes in EUV emission. Difference in the electron density and temperature in different holes or different parts of a hole can account for the diversity of manifestations of coronal holes. Estimates showed that the influence of these parameters is strongest in the wavelength range of 2-5 cm. Depending on particular values of the coronal electron density and temperature, coronal holes are either indistinguishable from the background of the quiet Sun, or show up as regions of decreased or increased microwave emission.