Observational Signatures of Tearing Instability in the Current Sheet of a Solar Flare

TL;DR

This paper presents observational evidence of tearing instability in a solar flare's current sheet, demonstrating plasmoid formation, plasma dynamics, and particle acceleration through multi-wavelength imaging, advancing understanding of magnetic reconnection.

Contribution

It provides detailed multi-wavelength observations of plasmoid formation and evolution in a solar flare, offering new insights into tearing instability and magnetic reconnection processes.

Findings

Detection of multiple plasmoids in EUV images

Observation of nonthermal X-ray emission at plasmoid locations

Radio structures indicating plasmoid evolution and dynamics

Abstract

Magnetic reconnection is a fundamental physical process converting magnetic energy into not only plasma energy but also particle energy in various astrophysical phenomena. In this letter, we show a unique dataset of a solar flare where various plasmoids were formed by a continually stretched current sheet. EUV images captured reconnection inflows, outflows, and particularly the recurring plasma blobs (plasmoids). X-ray images reveal nonthermal emission sources at the lower end of the current sheet, presumably as large plasmoids with a sufficiently amount of energetic electrons trapped in. In the radio domain, an upward slowly drifting pulsation structure, followed by a rare pair of oppositely drifting structures, was observed. These structures are supposed to map the evolution of the primary and the secondary plasmoids formed in the current sheet. Our results on plasmoids at different locations and scales shed important light on the dynamics, plasma heating, particle acceleration, and transport processes in the turbulent current sheet and provide observational evidence for the cascading magnetic reconnection process.