Multi-Wavelength Observation of Electron Acceleration in the 2006 December 13 Flare

TL;DR

This study combines multi-wavelength observations from Hinode, RHESSI, and Nobeyama to investigate electron acceleration mechanisms during the December 13, 2006 solar flare, highlighting the role of magnetic separatrices.

Contribution

It provides new observational evidence linking electron acceleration sites to magnetic separatrices using combined optical, X-ray, and radio data.

Findings

HXR sources are located at regions with changing horizontal magnetic fields.

Microwave emissions indicate electron acceleration near magnetic separatrices.

Loop structures connect HXR sources, supporting acceleration along magnetic field lines.

Abstract

We present a multi-wavelength observation of a solar flare occurring on 2006 December 13 with Hinode, RHESSI, and the Nobeyama Radio Observatory, to study the electron acceleration site and mechanism. The Solar Optical Telescope (SOT) on board Hinode observed elongated flare ribbons, and RHESSI observed double-footpoint hard X-ray (HXR) sources appearing in part of the ribbons. A photospheric vector magnetogram obtained from SOT reveals that the HXR sources are located at the region where horizontal magnetic fields change the direction. The region is interpreted as the footpoint of magnetic separatrix. Microwave images taken with the Nobeyama Radioheliograph show a loop structure connecting the HXR sources. The brighter parts of the microwave intensity are located between the top and footpoints of the loop. We consider these observations as an evidence of the electron acceleration near the magnetic separatrix and injection parallel to the field line.