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Communication Dans Un Congrès Année : 2022

Multiscale analysis of a current sheet crossing associated with a fast earthward flow during a substorm event detected by MMS

Olivier Le Contel
Alessandro Retino
Thomas Chust
Daniel Gershman
Daniel Graham

Résumé

<p><span>In July 2017, the MMS constellation was evolving in the magnetotail with an apogee of 25 Earth radii and an average inter-satellite distance of 10 km (i.e. at electron scales). On 23</span><sup><span>rd</span></sup><span> of July around 16:19 UT, MMS was located at the edge of the current sheet which was in a quasi-static state. Then, MMS suddenly entered in the central plasma sheet and detected the local onset of a small substorm as indicated by the AE index (~400 nT). Fast plasma flows towards the Earth were measured for about 1 hour starting with a period of quasi-steady flow and followed by a series of saw-tooth plasma jets (&#8220;bursty bulk flows&#8221;). In the present study, we focus on a short sequence related to the crossing of an ion scale current sheet embedded in a fast earthward flow. The current sheet appears to be corrugated and with a significant guide field (BL/BM~0.5). Tailward propagating electrostatic solitary waves are detected just after the magnetic equator crossing and at the edge of the current sheet. We also analyze in detail an electron vortex magnetic hole also detected at the edge of this current sheet and discuss the Ohm&#8217;s law and energy conversion processes. We find that the energy dissipation associated with the electron vortex is three times greater (0.15nW/m3) than at the current sheet crossing (0.05nW/m3). Based on estimated statistical weight of these vortices we discuss possible consequences for the energy dissipation associated with fast earthward plasma flows.</span></p>
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Dates et versions

hal-03916801 , version 1 (31-12-2022)

Identifiants

Citer

Olivier Le Contel, Alessandro Retino, Alexandra Alexandrova, Rumi Nakamura, Soboh Alqeeq, et al.. Multiscale analysis of a current sheet crossing associated with a fast earthward flow during a substorm event detected by MMS. EGU22, the 24th EGU General Assembly, May 2022, Vienne, Austria. ⟨10.5194/egusphere-egu22-9481⟩. ⟨hal-03916801⟩
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