Observations on the slowly varying component of solar radio emission at decameter wavelengths

Abstract

The authors have made two-dimensional maps of the slowly varying component (SVC) of solar radio emission at a frequency of 34.5 MHz with half power beam width of 26'/40'. It is found that a majority of SVC sources have brightness temperatures of the order of 0.5×106K and half power widths of about 4 R_sun;. The shifts in the positions of the centroids of the SVC sources from the center of the Sun were in the range 1.5 to 2 R_sun;. These observations can be explained in terms of thermal emission from coronal regions of enhanced density and temperature located at distances of 1.5 to 2 R_sun; from the center of the Sun.