New results on the direct observations of thermal radio emission from a solar coronal mass ejection

Abstract: We report observations of thermal emission from the frontal structure of a coronal mass ejection (CME) using data obtained with the Gauribidanur RAdioheliograPH (GRAPH) simultaneously at 80 MHz and 53 MHz on 2016 May 1. The CME was due to activity on the far-side of the Sun, but near its limb. No non-thermal radio burst activity were noticed. This provided an opportunity to observe the faint thermal radio emission from the CME, and hence directly estimate the electron density, mass, and magnetic field strength of the plasma entrained in the CME. Considering that CMEs are mostly observed only in whitelight and reports on their plasma characteristics are also limited, the rare direct radio observations of thermal emission from a CME and independent diagnosis of its plasma parameters are important measurements in the field of CME physics.