Electron acceleration in a post-flare decimetric continuum source

Abstract

Aims: to calculate the power budget for electron acceleration and the efficiency of the plasma emission mechanism in a post-flare decimetric continuum source. Methods: We have imaged a high brightness temperature (∼10⁹K) post-flare source at 1060 MHz with the Giant Metrewave Radio Telescope (GMRT). We use information from these images and the dynamic spectrum from the Hiraiso spectrograph together with the theoretical method described in Subramanian & Becker (2006) to calculate the power input to the electron acceleration process. The method assumes that the electrons are accelerated via a second-order Fermi acceleration mechanism. Results: We find that the power input to the nonthermal electrons is in the range 3 × 10²⁵ -10²⁶ erg/s. The efficiency of the overall plasma emission process starting from electron acceleration and culminating in the observed emission could range from 2.87 ×10^-9 to 2.38 ×10^-8.