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ORIGINAL RESEARCH article

Front. Astron. Space Sci.
Sec. Space Physics
Volume 11 - 2024 | doi: 10.3389/fspas.2024.1427791
This article is part of the Research Topic Magnetosheaths View all 7 articles

Spatial Distribution of the Plasma Density and Magnetic Field Amplitude in the Dayside Magnetosheath as a Function of the IMF Orientation

Provisionally accepted
Bayane Michotte De Welle Bayane Michotte De Welle 1*Nicolas Aunai Nicolas Aunai 1Benoit Lavraud Benoit Lavraud 2Vincent N. Génot Vincent N. Génot 3Alexis Jeandet Alexis Jeandet 1Gautier Nguyen Gautier Nguyen 4Ambre Ghisalberti Ambre Ghisalberti 1Roch Smets Roch Smets 1
  • 1 UMR7648 Laboratoire de physique des plasmas (LPP), Palaiseau, France
  • 2 UMR5804 Laboratoire d'astrophysique de Bordeaux (LAB), Pessac, Aquitaine, France
  • 3 UMR5277 Institut de recherche en astrophysique et planétologie (IRAP), Toulouse, Midi-Pyrénées, France
  • 4 Centre de Toulouse, Office National d'Études et de Recherches Aérospatiale, Toulouse, France

The final, formatted version of the article will be published soon.

    The properties of the magnetosheath are of pivotal importance in determining the coupling between the magnetosphere and the interplanetary medium. In particular, the magnetic flux pileup and plasma depletion layer (PDL) modify the boundary conditions of magnetopause reconnection. However, the spatial distribution of the magnetic field strength and plasma density in the magnetosheath, as well as their functional dependence on the interplanetary magnetic field (IMF) orientation, remain not well understood and is characterized in detail in this study through the statisical processing of decades of data from Cluster, Double Star, THEMIS, MMS. The first part of this study focuses on the so far poorly known variations across the magnetosheath from the shock to the magnetopause. The magnetic pileup and PDL are found to be significantly correlated, with a strong dependence on the IMF cone angle. Their dependence on the IMF clock angle is found only nearby the magnetopause, consistently with the expected effect of magnetic reconnection. The second part of this study examines the asymmetry in the magnetic field amplitude and density between the quasi-parallel and quasi-perpendicular sides of the equatorial magnetosheath. These asymmetries characterize for different relative distances to the magnetopause and bow shock boundaries, and as a function of the IMF orientation. The magnetic field amplitude, observed to be higher on the quasi-perpendicular side of the magnetosheath, become more symmetric on approaching the magnetopause. The quasi-parallel magnetosheath exhibits higher plasma density near the magnetopause. However, the asymmetry reverses about the mid-magnetosheath with decreasing IMF cone angle.

    Keywords: magnetosheath, magnetic pileup, Plasma depletion layer, asymmetry, density, Magnetic Field Amplitude, Magnetopause

    Received: 04 May 2024; Accepted: 04 Jul 2024.

    Copyright: © 2024 Michotte De Welle, Aunai, Lavraud, Génot, Jeandet, Nguyen, Ghisalberti and Smets. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Bayane Michotte De Welle, UMR7648 Laboratoire de physique des plasmas (LPP), Palaiseau, France

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