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Near-Earth plasma sheet boundary dynamics during substorm dipolarization

Authors :
Rumi Nakamura
Tsugunobu Nagai
Joachim Birn
Victor A. Sergeev
Olivier Le Contel
Ali Varsani
Wolfgang Baumjohann
Takuma Nakamura
Sergey Apatenkov
Anton Artemyev
Robert E. Ergun
Stephen A. Fuselier
Daniel J. Gershman
Barbara J. Giles
Yuri V. Khotyaintsev
Per-Arne Lindqvist
Werner Magnes
Barry Mauk
Christopher T. Russell
Howard J. Singer
Julia Stawarz
Robert J. Strangeway
Brian Anderson
Ken R. Bromund
David Fischer
Laurence Kepko
Guan Le
Ferdinand Plaschke
James A. Slavin
Ian Cohen
Allison Jaynes
Drew L. Turner
Source :
Earth, Planets and Space, Vol 69, Iss 1, Pp 1-14 (2017)
Publication Year :
2017
Publisher :
SpringerOpen, 2017.

Abstract

Abstract We report on the large-scale evolution of dipolarization in the near-Earth plasma sheet during an intense (AL ~ −1000 nT) substorm on August 10, 2016, when multiple spacecraft at radial distances between 4 and 15 R E were present in the night-side magnetosphere. This global dipolarization consisted of multiple short-timescale (a couple of minutes) B z disturbances detected by spacecraft distributed over 9 MLT, consistent with the large-scale substorm current wedge observed by ground-based magnetometers. The four spacecraft of the Magnetospheric Multiscale were located in the southern hemisphere plasma sheet and observed fast flow disturbances associated with this dipolarization. The high-time-resolution measurements from MMS enable us to detect the rapid motion of the field structures and flow disturbances separately. A distinct pattern of the flow and field disturbance near the plasma boundaries was found. We suggest that a vortex motion created around the localized flows resulted in another field-aligned current system at the off-equatorial side of the BBF-associated R1/R2 systems, as was predicted by the MHD simulation of a localized reconnection jet. The observations by GOES and Geotail, which were located in the opposite hemisphere and local time, support this view. We demonstrate that the processes of both Earthward flow braking and of accumulated magnetic flux evolving tailward also control the dynamics in the boundary region of the near-Earth plasma sheet. Graphical Abstract Multispacecraft observations of dipolarization (left panel). Magnetic field component normal to the current sheet (BZ) observed in the night side magnetosphere are plotted from post-midnight to premidnight region: a GOES 13, b Van Allen Probe-A, c GOES 14, d GOES 15, e MMS3, g Geotail, h Cluster 1, together with f a combined product of energy spectra of electrons from MMS1 and MMS3 and i auroral electrojet indices. Spacecraft location in the GSM X-Y plane (upper right panel). Colorcoded By disturbances around the reconnection jets from the MHD simulation of the reconnection by Birn and Hesse (1996) (lower right panel). MMS and GOES 14-15 observed disturbances similar to those at the location indicated by arrows

Details

Language :
English
ISSN :
18805981
Volume :
69
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Earth, Planets and Space
Publication Type :
Academic Journal
Accession number :
edsdoj.f74c6b13e64146f7a5051e9333cb2d3c
Document Type :
article
Full Text :
https://doi.org/10.1186/s40623-017-0707-2