Fine Structures of the Electron Current Sheet in Magnetotail Guide‐Field Reconnection. Issue 9 (5th May 2022)

• Record Type: Journal Article
• Authors: Tang, B.‐B.; Li, W. Y.; Khotyaintsev, Yu. V.; Graham, D. B.; Gao, C. H.; Chen, Z. Z.; Fu, H. S.; Lu, Q. M.; Wang, C.; Burch, J. L.
• Is Part Of: Geophysical research letters. Volume 49:Issue 9(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-05-05
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2021GL097573
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We investigate fine structures of the electron current sheet in magnetotail guide‐field reconnection using Magnetospheric Multiscale observations. This current sheet, observed in the outer electron diffusion region (EDR) of reconnection, is featured by clear bifurcation and deflection, and also has complicated fine sublayers. The formation of these sublayers is closely related to streaming and meandering electrons, which are facilitated by the reconnection guide field. In particular, in the sublayer around the BL reversal, the meandering electrons, which usually move along the out‐of‐plane (M) direction, are strongly distorted into the vL ‐vN plane due to the finite BM component. The low frequency fluctuation of this current sheet is also revealed, contributing ∼3% of the reconnection electric field by the anomalous effect. We suggest that such current sheet fluctuations, possibly driven by the magnetic double‐gradient instability, can be characteristic in the outer EDR. Plain Language Summary: The electron‐scale current sheet forms a basic feature of the electron diffusion region of magnetic reconnection, in which the topology of magnetic field lines changes and various electron processes occur. However, owing to its thinness, the fine structure of the electron current sheet has not been fully investigated, despite some general configurations having been reported. In this study, by using high‐resolution measurements from Magnetospheric Multiscale mission, we present fine structures of an electron current sheet in guide‐field reconnection, and show how these fine structures are closely related to the electron motion. Besides, the low frequency fluctuation of this current sheet is also revealed. These results provide new insight to reconnection dynamics at electron scales. Key Points: Fine structures of an electron current sheet in the electron diffusion region are presented The formation of these structures are closely related to the streaming and meandering electrons The low frequency fluctuation of this current sheet is also revealed