A Reconnecting Current Sheet Imaged in A Solar Flare

TL;DR

This paper presents the first clear observation of a reconnecting current sheet during a solar flare, providing direct evidence of magnetic reconnection in the solar corona.

Contribution

It reports the imaging of a large, bright current sheet in EUV during a solar flare, confirming theoretical models with direct observational evidence.

Findings

Imaged a bright current sheet >0.25 solar radii in length

Observed reconnection signatures consistent with theoretical predictions

Provided detailed view of reconnection geometry and dynamics

Abstract

Magnetic reconnection changes the magnetic field topology and powers explosive events in astrophysical, space and laboratory plasmas. For flares and coronal mass ejections (CMEs) in the solar atmosphere, the standard model predicts the presence of a reconnecting current sheet, which has been the subject of considerable theoretical and numerical modeling over the last fifty years, yet direct, unambiguous observational verification has been absent. In this Letter we show a bright sheet structure of global length (>0.25 Rsun) and macroscopic width ((5 - 10)x10^3 km) distinctly above the cusp-shaped flaring loop, imaged during the flare rising phase in EUV. The sheet formed due to the stretch of a transequatorial loop system, and was accompanied by various reconnection signatures that have been dispersed in the literature. This unique event provides a comprehensive view of the reconnection geometry and dynamics in the solar corona.