The structure of a perturbed magnetic reconnection electron diffusion region

TL;DR

This paper presents in situ observations of a perturbed electron diffusion region during magnetic reconnection, revealing complex oscillations and motions that challenge the assumption of a steady 2D reconnection model.

Contribution

It provides the first detailed analysis of a perturbed EDR, highlighting the importance of three-dimensional effects and dynamic motions in magnetic reconnection.

Findings

Significant magnetic field oscillations near the lower hybrid frequency.

Oscillations in electron-scale gradients close to the EDR.

Complex motion of the reconnection plane due to current sheet kinking.

Abstract

We report in situ observations of an electron diffusion region (EDR) and adjacent separatrix region. We observe significant magnetic field oscillations near the lower hybrid frequency which propagate perpendicularly to the reconnection plane. We also find that the strong electron-scale gradients close to the EDR exhibit significant oscillations at a similar frequency. Such oscillations are not expected for a crossing of a steady 2D EDR, and can be explained by a complex motion of the reconnection plane induced by current sheet kinking propagating in the out-of-reconnection-plane direction. Thus all three spatial dimensions have to be taken into account to explain the observed perturbed EDR crossing.