Observations of Turbulent Magnetic Reconnection Within a Solar Current Sheet

TL;DR

This paper presents direct observational evidence of fragmented and turbulent magnetic reconnection in a solar current sheet during a major solar flare, highlighting the complex dynamics involved.

Contribution

It provides the first direct observations of turbulence and fragmentation in magnetic reconnection within a solar current sheet, supporting theoretical models.

Findings

Detection of plasma heating and non-thermal motions in the current sheet.

Observation of intermittent, power-law distributed outflow jets.

Evidence of tearing mode instability in the current sheet.

Abstract

Magnetic reconnection is a fundamental physical process in various astrophysical, space, and laboratory environments. Many pieces of evidence for magnetic reconnection have been uncovered. However, its specific processes that could be fragmented and turbulent have been short of direct observational evidence. Here, we present observations of a super-hot current sheet during SOL2017-09-10T X8.2-class solar flare that display the fragmented and turbulent nature of magnetic reconnection. As bilateral plasmas converge toward the current sheet, significant plasma heating and non-thermal motions are detected therein. Two oppositely directed outflow jets are intermittently expelled out of the fragmenting current sheet, whose intensity shows a power-law distribution in spatial frequency domain. The intensity and velocity of the sunward outflow jets also display a power-law distribution in temporal frequency domain. The length-to-width ratio of the current sheet is estimated to be larger than theoretical threshold of and thus ensures occurrence of tearing mode instability. The observations therefore suggest fragmented and turbulent magnetic reconnection occurring in the long stretching current sheet.