Energy budget of plasma motions, heating, and electron acceleration in a three-loop solar flare

TL;DR

This study analyzes the energy distribution in a solar flare, revealing how magnetic energy is partitioned among thermal plasma, nonthermal particles, and kinetic motions across multiple loops using multi-wavelength data and 3D modeling.

Contribution

It provides detailed quantification of energy partitioning and spatial distribution in a multi-loop solar flare, highlighting the uneven energy division and the presence of multiple heating episodes.

Findings

Energy is divided unevenly between thermal and nonthermal components.

Only one loop contains significant nonthermal electrons.

Kinetic energy in footpoints is minor compared to thermal and nonthermal energies.

Abstract

Non-potential magnetic energy promptly released in solar flares is converted to other forms of energy. This may include nonthermal energy of flare-accelerated particles, thermal energy of heated flaring plasma, and kinetic energy of eruptions, jets, up/down flows, and stochastic (turbulent) plasma motions. The processes or parameters governing partitioning of the released energy between these components is an open question. How these components are distributed between distinct flaring loops and what controls these spatial distributions is also unclear. Here, based on multi-wavelength data and 3D modeling, we quantify the energy partitioning and spatial distribution in the well observed SOL2014-02-16T064620 solar flare of class C1.5. Nonthermal emissions of this flare displayed a simple impulsive single-spike light curves lasting about 20\,s. In contrast, the thermal emission demonstrated at least three distinct heating episodes, only one of which was associated with the nonthermal component. The flare was accompanied by up and down flows and substantial turbulent velocities. The results of our analysis suggest that (i) the flare occurs in a multi-loop system that included at least three distinct flux tubes; (ii) the released magnetic energy is divided unevenly between the thermal and nonthermal components in these loops; (iii) only one of these three flaring loops contains an energetically important amount of nonthermal electrons, while two other loops remain thermal; (iv) the amounts of direct plasma heating and that due to nonthermal electron loss are comparable; (v) the kinetic energy in the flare footpoints constitute only a minor fraction compared with the thermal and nonthermal energies.