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Communication Dans Un Congrès Année : 2017

Kinetic Studies of Thin Current Sheets at Magnetosheath Jets

E. Eriksson
  • Fonction : Auteur
D. B. Graham
  • Fonction : Auteur
E. Yordanova
  • Fonction : Auteur
H. Hietala
  • Fonction : Auteur
S. Markidis
  • Fonction : Auteur
B. L. Giles
  • Fonction : Auteur
M. André
C. T. Russell
  • Fonction : Auteur
Olivier Le Contel
J. L. Burch
  • Fonction : Auteur

Résumé

In near-Earth space one of the most turbulent plasma environments is the magnetosheath (MSH) downstream of the quasi-parallel shock. The particle acceleration and plasma thermalization processes there are still not fully understood. Regions of strong localized currents are believed to play a key role in those processes. The Magnetospheric Multiscale (MMS) mission has sufficiently high cadence to study these processes in detail. We present details of studies of two different events that contain strong current regions inside the MSH downstream of the quasi-parallel shock. In both cases the shape of the current region is in the form of a sheet, however they show internal 3D structure on the scale of the spacecraft separation (15 and 20 km, respectively). Both current sheets have a normal magnetic field component different from zero indicating that the regions at the different sides of the current sheets are magnetically connected. Both current sheets are boundaries between two different plasma regions. Furthermore, both current sheets are observed at MSH jets. These jets are characterized by localized dynamic pressure being larger than the solar wind dynamic pressure. One current sheet does not seem to be reconnecting while the other shows reconnection signatures. Inside the non-reconnecting current sheet we observe locally accelerated electron beams along the magnetic field. At energies above the beam energy we observe a loss cone consistent with part of the hot MSH-like electrons escaping into the colder solar wind-like plasma. This suggests that the acceleration process within this current sheet is similar to the one that occurs at the bow shock, where electron beams and loss cones are also observed. Therefore, we conclude that electron beams observed in the MSH do not have to originate from the bow shock, but can also be generated locally inside the MSH. The reconnecting current sheet also shows signs of thermalization and electron acceleration processes that are discussed in detail.
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Dates et versions

hal-02796713 , version 1 (05-06-2020)

Identifiants

  • HAL Id : hal-02796713 , version 1

Citer

E. Eriksson, A. Vaivads, Y. V. Khotyaintsev, D. B. Graham, E. Yordanova, et al.. Kinetic Studies of Thin Current Sheets at Magnetosheath Jets. AGU Fall meeting, Dec 2017, New Orleans, Louisiane, United States. ⟨hal-02796713⟩
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