X-ray and UV investigation into the magnetic connectivity of a solar flare

TL;DR

This study analyzes X-ray and UV emissions during a solar flare to understand its evolution, revealing two distinct emission phases, spatial correlations, and the role of magnetic reconnection processes.

Contribution

It provides new insights into the magnetic topology and reconnection mechanisms driving the flare's evolution through combined X-ray and UV observations.

Findings

Two emission phases separated by 25 seconds

Good spatial and temporal correlation between X-ray and UV emissions

Reconnection processes involve quasi separatrix layer and null-point reconnection

Abstract

We investigate the X-ray and UV emission detected by RHESSI and TRACE in the context of a solar flare on the 16th November 2002 with the goal of better understanding the evolution of the flare. We analysed the characteristics of the X-ray emission in the 12-25 and 25-50 keV energy range while we looked at the UV emission at 1600 {\AA}. The flare appears to have two distinct phases of emission separated by a 25-second time delay, with the first phase being energetically more important. We found good temporal and spatial agreement between the 25-50 keV X-rays and the most intense areas of the 1600 {\AA} UV emission. We also observed an extended 100-arcsecond < 25 keV source that appears coronal in nature and connects two separated UV ribbons later in the flare. Using the observational properties in X-ray and UV wavelengths, we propose two explanations for the flare evolution in relation to the spine/fan magnetic field topology and the accelerated electrons. We find that a combination of quasi separatrix layer reconnection and null-point reconnection is required to account for the observed properties of the X-ray and UV emission.