Energy Budget of Plasma Motions, Heating, and Electron Acceleration in a Three-loop Solar Flare

Abstract

Nonpotential 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, upflows/downflows, and stochastic (turbulent) plasma motions. The processes or parameters governing partitioning of the released energy between these components are an open question. How these components are distributed between distinct flaring loops and what controls these spatial distributions are also unclear. Here, based on multiwavelength 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 emission of this flare displayed a simple impulsive single-spike light curve 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 upflows and downflows and substantial turbulent velocities. The results of our analysis suggest that (i) the flare occurs in a multiloop 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; and (v) the kinetic energy in the flare footpoints constitutes only a minor fraction compared with the thermal and nonthermal energies.

Observations of Magnetic Reconnection and Particle Acceleration Locations in Solar Coronal Jets

“…However, the energy partition between the jet and the associated flares is different from the energy partition between a CME and a flare. For this event, the kinetic/gravitational energy of the jet is more than one order of magnitude smaller than the energy of the flares (thermal/nonthermal), while in Emslie et al (2012), the total energy of the CME is usually significantly larger-the kinetic energy in confined flares is much smaller (Fleishman et al 2021), though. This variety could be explained in the minifilament eruption scenario, with jets and CMEs being parts of the same eruptive events, but with the energy partition changing with scale; or it could also indicate that there are fundamental differences between jets and CMEs.…”

“…Similar results were found in a later study by Warmuth & Mann (2016), where the median ratio of thermal energies to nonthermal energies in the electrons for 24 (C-to-X class) flares was 0.3. In a subclass of "cold" flares (Lysenko et al 2018), the thermal energy is equal (within the uncertainties) to the nonthermal energy deposition (Fleishman et al 2016;Motorina et al 2020;Fleishman et al 2021). (Theoretically, the thermal energy cannot be less than the nonthermal energy, as the nonthermal energy decays into the thermal energy.)…”

Data-constrained Solar Modeling with GX Simulator

“…However, one may choose to skip this step of the model production pipeline, and assign instead a chromosphere represented by a uniform slab of adjustable height, constant temperature T chr , and constant density n chr , interactively chosen through the GX Simulator GUI, this option being available for any of the POT, NAS, NAS.GEN, or POT.GEN models produced by the pipeline. This simpler option is often appropriate for modeling of flaring loops Kuroda et al 2018;Fleishman et al 2018Fleishman et al , 2021b.…”

X-ray fine structure of a limb solar flare revealed by Insight-HXMT, RHESSI and Fermi

“…In standard scenario high energy electrons propagates from higher corona into the dense chromosphere along complex magnetic loop (Benz 2017). It's natural that if we could obtain the precise 3D morphology structure of the flare and its evolution, which could be very helpful for better modeling of the physic process, determinate the energy budget and its conversion efficiency (Fleishman et al 2021). But almost all ground and space observations only provide line of sight in field of view, projection effect becomes very important, which causes discrepancy between the observations and theory (Forbes & Acton 1996), especially for detailed energy release and dissipation processes (Warmuth & Mann 2016).…”