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

Abstract

Two-dimensional maps have been made 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 arcmin. It is found that a majority of SVC sources have brightness temperatures of the order of 500.000 K, and half-power widths of about 4 solar radii. 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 solar radii. 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 solar radii from the center of the sun.