An Intriguing Solar Microflare Observed with RHESSI, Hinode and TRACE

TL;DR

This study examines a solar microflare using multi-instrument observations to analyze particle acceleration and heating, revealing unexpected spectral and temporal behaviors that challenge standard flare models.

Contribution

It provides detailed imaging and spectral analysis of a microflare with high-energy non-thermal emissions, highlighting deviations from classical flare expectations.

Findings

Non-thermal emission extends above 50 keV.

Hard X-ray burst does not follow the Neupert effect.

Non-thermal spectrum may extend down to 4 keV.

Abstract

Investigate particle acceleration and heating in a solar microflare. In a microflare with non-thermal emission to remarkably high energies ($>50$ keV), we investigate the hard X-rays with RHESSI imaging and spectroscopy and the resulting thermal emission seen in soft X-rays with Hinode/XRT and in EUV with TRACE. The non-thermal footpoints observed with RHESSI spatially and temporally match bright footpoint emission in soft X-rays and EUV. There is the possibility that the non-thermal spectrum extends down to 4 keV. The hard X-ray burst clearly does not follow the expected Neupert effect, with the time integrated hard X-rays not matching the soft X-ray time profile. So although this is a simple microflare with good X-ray observation coverage it does not fit the standard flare model.