Microwave Emission of Supra-arcade Structure associated with M1.6 Limb Flare

TL;DR

This study investigates microwave and X-ray emissions from a supra-arcade structure during an M1.6 solar flare, revealing gradual microwave brightness temperature increase and dual soft X-ray sources, providing insights into flare plasma characteristics.

Contribution

It presents new observational analysis of microwave and soft X-ray emissions from a supra-arcade structure, highlighting its thermal properties and emission evolution during a solar flare.

Findings

Microwave brightness temperature increased up to 2×10^4 K.

Two soft X-ray sources were identified: one with the supra-arcade and one above the post-flare arcade.

Derived plasma parameters such as emission measure, density, and energy of the structure.

Abstract

We have investigated a supra-arcade structure, associated with an M1.6 flare, which occurred on the south-east limb on 4th of November 2010. It is observed in microwaves at 17 GHz with the Nobeyama Radioheliograph (NoRH), soft X-rays in the range of 8-20 keV with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and EUV with the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). As reported by Reeves & Golub (2011), the supra-arcade structure is observed predominantly in the AIA 131 {\AA} channel, which contains a hot 11 MK component from Fe XIX (Boerner et al. 2011). While this hot flare plasma lasts over the decay phase of the flare, it shows some interesting characteristics in microwaves and soft X-rays: 1) In the supra-arcade structure, the brightness temperature (TB) of the microwave emission increases gradually up to 2\times10^4 K, and 2) two soft X-ray sources appear: one cospatial with the supra-arcade structure and another above the post-flare arcade. We have derived the variation of emission measure, density, and energy of the supra-arcade structure using the TB obtained from 17 GHz microwave observations.