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Title: Characterizing Ion Flows Across a Magnetotail Dipolarization Jet: Characterizing Ion Flows Across a Magnetotail Dipolarization Jet
Award ID(s):
1805829
NSF-PAR ID:
10097833
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
Journal of Geophysical Research: Space Physics
Volume:
123
Issue:
8
ISSN:
2169-9380
Page Range / eLocation ID:
6326 to 6334
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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  1. Abstract

    This paper addresses the question of the contribution of azimuthally localized flow channels and magnetic field dipolarizations embedded in them in the global dipolarization of the inner magnetosphere during substorms. We employ the high‐resolution Lyon‐Fedder‐Mobarry global magnetosphere magnetohydrodynamic model and simulate an isolated substorm event, which was observed by the geostationary satellites and by the Magnetospheric Multiscale spacecraft. The results of our simulations reveal that plasma sheet flow channels (bursty bulk flows, BBFs) and elementary dipolarizations (dipolarization fronts, DFs) occur in the growth phase of the substorm but are rare and do not penetrate to the geosynchronous orbit. The substorm onset is characterized by an abrupt increase in the occurrence and intensity of BBFs/DFs, which penetrate well earthward of the geosynchronous orbit during the expansion phase. These azimuthally localized structures are solely responsible for the global (in terms of the magnetic local time) dipolarization of the inner magnetosphere toward the end of the substorm expansion. Comparison with the geostationary satellites and Magnetospheric Multiscale data shows that the properties of the BBFs/DFs in the simulation are similar to those observed, which gives credence to the above results. Additionally, the simulation reveals many previously observed signatures of BBFs and DFs, including overshoots and oscillations around their equilibrium position, strong rebounds and vortical tailward flows, and the corresponding plasma sheet expansion and thinning.

     
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