Plasma heating in the very early and decay phases of solar flares

TL;DR

This study analyzes the energy contribution of non-thermal electrons in solar flares, demonstrating they are sufficient for plasma heating throughout all phases, including decay, without additional mechanisms.

Contribution

It provides detailed energy budget analysis showing non-thermal electrons alone can account for plasma heating in solar flares, challenging the need for other heating mechanisms.

Findings

Non-thermal electrons supply sufficient energy during all flare phases.

Energy fluxes from RHESSI data match observed GOES light-curves.

No additional heating mechanisms are necessary for the studied flares.

Abstract

In this paper we analyze the energy budgets of two single-loop solar flares under the assumption that non-thermal electrons are the only source of plasma heating during all phases of both events. The flares were observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Geostationary Operational Environmental Satellite (GOES) on September 20, 2002 and March 17, 2002, respectively. For both investigated flares we derived the energy fluxes contained in non-thermal electron beams from the RHESSI observational data constrained by observed GOES light-curves. We showed that energy delivered by non-thermal electrons was fully sufficient to fulfil the energy budgets of the plasma during the pre-heating and impulsive phases of both flares as well as during the decay phase of one of them. We concluded that in the case of the investigated flares there was no need to use any additional ad-hoc heating mechanisms other than heating by non-thermal electrons.