# Energy partition in two M-class circular-ribbon flares

## TL;DR

This study analyzes the energy distribution in two homologous M-class circular-ribbon solar flares, quantifying thermal, nonthermal, and radiative energies, and assessing their interrelations and energy sources.

## Contribution

It provides detailed energy partitioning analysis of two homologous circular-ribbon flares using multi-instrument observations, highlighting the energy contributions and losses.

## Key findings

- Peak thermal energies are approximately 1.94×10^{30} erg.
- Nonthermal energies in flare-accelerated electrons are about 3.9×10^{30} erg.
- Radiative outputs in 1-70 Å are ~200 times greater than in 1-8 Å, accounting for ~62.5% of thermal energy.

## Abstract

In this paper, we investigate the energy partition of two homologous M1.1 circular-ribbon flares (CRFs) in active region (AR) 12434. They were observed by \textit{SDO}, \textit{GOES}, and \textit{RHESSI} on 2015 October 15 and 16, respectively. The peak thermal energy, nonthermal energy of flare-accelerated electrons, total radiative loss of hot plasma, and radiant energies in 1$-$8 {\AA} and 1$-$70 {\AA} of the flares are calculated. The two flares have similar energetics. The peak thermal energies are (1.94$\pm$0.13)$\times$10$^{30}$ erg. The nonthermal energies in flare-accelerated electrons are (3.9$\pm$0.7)$\times$10$^{30}$ erg. The radiative outputs of the flare loops in 1$-$70 {\AA}, which are $\sim$200 times greater than the outputs in 1$-$8 {\AA}, account for $\sim$62.5\% of the peak thermal energies. The radiative losses of SXR-emitting plasma are one order of magnitude lower than the peak thermal energies. Therefore, the total heating requirements of flare loops including radiative loss are (2.1$\pm$0.1)$\times$10$^{30}$ erg, which could sufficiently be supplied by nonthermal electrons.