Signatures of magnetic separatrices at the borders of a crater flux transfer event connected to an active X‐line
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
In this paper, we present Magnetospheric Multiscale (MMS) observations of a flux transfer event (FTE) characterized by a clear signature in the magnetic field magnitude, which shows maximum at the center flanked by two depressions, detected during a period of stable southward interplanetary magnetic field. This class of FTEs are called “crater‐FTEs” and have been suggested to be connected with active reconnection X line. The MMS burst mode data allow the identification of intense fluctuations in the components of the electric field and electron velocity parallel to the magnetic field at the borders of the FTE, which are interpreted as signatures of the magnetic separatrices. In particular, the strong and persistent fluctuations of the parallel electron velocity at the borders of this crater‐FTE reported for the first time in this paper, sustain the field‐aligned current part of the Hall current system along the separatrix layer, and confirm that this FTE is connected with an active reconnection X line. Our observations suggest a stratification of particles inside the reconnection layer, where electrons are flowing toward the X line along the separatrix, are flowing away from the X line along the reconnected field lines adjacent to the separatrices, and more internally ions and electrons are flowing away from the X line with comparable velocities, forming the reconnection jets. This stratification of the reconnection layer forming the FTE, together with the reconnection jet at the trailing edge of the FTE, suggests clearly that this FTE is formed by the single X line generation mechanism.
Date Issued
2019-11-09
Date Acceptance
2019-09-27
Citation
Journal of Geophysical Research: Space Physics, 2019, 124 (11), pp.8600-8616
ISSN
2169-9380
Publisher
American Geophysical Union (AGU)
Start Page
8600
End Page
8616
Journal / Book Title
Journal of Geophysical Research: Space Physics
Volume
124
Issue
11
Copyright Statement
©2019. American Geophysical Union. All Rights Reserved. This is the accepted version of the following article: Trenchi, L., Coxon, J. C., Fear, R. C., Eastwood, J. P., Dunlop, M. W., Trattner, K. J., et al ( 2019). Signatures of magnetic separatrices at the borders of a crater flux transfer event connected to an active X‐line. Journal of Geophysical Research: Space Physics, 124, which has been published in final form at https://doi.org/10.1029/2018JA026126
Sponsor
Science and Technology Facilities Council (STFC)
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JA026126
Grant Number
ST/N000692/1
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
DAYSIDE MAGNETOPAUSE
EARTHS MAGNETOPAUSE
RECONNECTION
PLASMA
BOUNDARY
FIELD
SHEAR
0201 Astronomical and Space Sciences
0401 Atmospheric Sciences
Publication Status
Published
Article Number
2018JA026126
Date Publish Online
2019-10-17