The Relationship Between EUV Nonthermal Line Broadening and High-energy Particle During Solar Flare

TL;DR

This study investigates the spatial relationship between EUV nonthermal line broadening and high-energy particles during large solar flares, revealing differences between thermal rich and thermal poor flares that suggest turbulence influences electron scattering.

Contribution

It provides new insights into the spatial dynamics of nonthermal broadening and microwave sources in different flare types, highlighting turbulence's role in high-energy electron behavior.

Findings

Nonthermal broadening occurs at the loop top in thermal rich flares.

Nonthermal broadening occurs at the footpoint in thermal poor flares.

Turbulence may influence electron pitch angle scattering.

Abstract

We have studied the relationship between the location of EUV nonthermal broadening and high-energy particles during the large flares by using EUV imaging spectrometer onboard {\it Hinode}, Nobeyama Radio Polarimeter, Nobeyama Radioheliograph, and Atmospheric Imaging Assembly onboard {\it Solar Dynamic Observatory}. We have analyzed the five large flare events which contain thermal rich, intermediate, and thermal poor flares classified by the definition discussed in the paper. We found that, in the case of thermal rich flares, the nonthermal broadening of \ion{Fe}{24} occurred at the top of the flaring loop at the beginning of the flares. The source of the 17 GHz microwave is located at the footpoint of the flare loop. On the other hand, in the case of intermediate/thermal poor flares, the nonthermal broadening of \ion{Fe}{24} occurred at the footpoint of the flare loop at the beginning of the flares. The source of the 17 GHz microwave is located at the top of the flaring loop. We discussed the difference between thermal rich and intermediate/thermal poor flare based on the spatial information of nonthermal broadening, which may give a clue for the presence of turbulence playing an important role in the pitch angle scattering of the high-energy electron.