Energy Release During Slow Long Duration Flares Observed by RHESSI

TL;DR

This study analyzes six Slow Long Duration Events (SLDEs) observed by RHESSI, revealing that their extended rising phase is due to prolonged heating rate decrease, characterized by smooth, long-lasting hard X-ray emissions.

Contribution

It provides detailed imaging spectroscopy analysis of SLDEs, linking their long rising phases to extended heating rate decay, a novel insight into their energy release process.

Findings

Long heating rate decrease explains extended rising phase.

SLDEs show smooth, long-lasting HXR emission without impulsive peaks.

Physical parameters derived from RHESSI data support energy balance analysis.

Abstract

Slow Long Duration Events (SLDEs) are flares characterized by long duration of rising phase. In many such cases impulsive phase is weak with lack of typical short-lasting pulses. Instead of that smooth, long-lasting Hard X-ray (HXR) emission is observed. We analysed hard X-ray emission and morphology of six selected SLDEs. In our analysis we utilized data from RHESSI and GOES satellites. Physical parameters of HXR sources were obtained from imaging spectroscopy and were used for the energy balance analysis. Characteristic time of heating rate decrease, after reaching its maximum value, is very long, which explains long rising phase of these flares.