Modeling Electron Acceleration and Transport in the Early Impulsive Phase of the 2017 September 10 Solar Flare

TL;DR

This study models electron acceleration and transport during the early impulsive phase of a major solar flare, using MHD simulations and Parker transport equation, revealing electron energies up to several MeV and spatial distributions consistent with observations.

Contribution

It introduces a comprehensive model combining MHD simulations and Parker transport equation to explain electron acceleration and distribution in a realistic flare geometry.

Findings

Electrons are accelerated up to several MeV.

Electron distributions match microwave and X-ray observations.

Large-scale electron filling in the reconnection region is confirmed.

Abstract

The X8.2-class limb flare on September 10, 2017 is among the best studied solar flare events owing to its great similarity to the standard flare model and the broad coverage by multiple spacecraft and ground-based observations. These multiwavelength observations indicate that electron acceleration and transport are efficient in the reconnection and flare looptop regions. However, there lacks a comprehensive model for explaining and interpreting the multi-faceted observations. In this work, we model the electron acceleration and transport in the early impulsive phase of this flare. We solve the Parker transport equation that includes the primary acceleration mechanism during magnetic reconnection in the large-scale flare region modeled by MHD simulations. We find that electrons are accelerated up to several MeV and fill a large volume of the reconnection region, similar to the observations shown in microwaves. The electron spatial distribution and spectral shape in the looptop region agree well with those derived from the microwave and hard X-ray emissions before magnetic islands grow large and dominate the acceleration. Future emission modelings using the electron maps will enable direct comparison with microwave and hard X-ray observations. These results shed new light on the electron acceleration and transport in a broad region of solar flares within a data-constrained realistic flare geometry.