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Massive multi-mission statistical study and analytical modeling of the Earth’s magnetopause: 2 - Shape and location
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  • Gautier Nguyen,
  • Nicolas Aunai,
  • Bayane Michotte de Welle,
  • Alexis Jeandet,
  • Benoit Lavraud,
  • Dominique Fontaine
Gautier Nguyen
Direction Générale de l'Armement

Corresponding Author:[email protected]

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Nicolas Aunai
IRAP, Toulouse, France
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Bayane Michotte de Welle
Ecole polytechnique
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Alexis Jeandet
Ecole polytechnique
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Benoit Lavraud
Institut de Recherche en Astrophysique et Planetologie - CNRS
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Dominique Fontaine
Laboratoire de Physique des Plasmas (LPP/CNRS), Paris, France
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Abstract

The Earth magnetopause is the boundary between the magnetosphere and the shocked solar wind. Its location and shape are primarily determined by the properties of the solar wind and interplanetary magnetic field (IMF) but the nature of the control parameters and to what extent they impact the stand-off distance, the flaring, and the symmetries, on the dayside and night side, is still not well known. We present a large statistical study of the magnetopause location and shape based a multi-mission magnetopause database, cumulating 17 230 crossings on 17 different spacecraft, from the dayside to lunar nightside distances. The IMF clock angle itself (all amplitudes combined) is fount not to impact the stand-off distance, nor does the cone angle. However, the magnetopause is found to move Earthward as the IMF gets stronger and more southward. All upstream conditions combined, it is found that the function used at the root of several analytical models still holds at lunar distances. The meridional flaring is found to depend on the seasonal tilt conditions, being larger in the summer hemisphere. The flaring is also found to depend on the IMF clock angle. Meridional flaring increases as the IMF turns south and is then larger than the equatorial flaring. The equatorial flaring barely changes or weakly increases as the IMF turns northward, and is larger than the meridional flaring for northward conditions. The study pave the way for the elaboration of a new analytical empirical expression magnetopause surface model.
Jan 2022Published in Journal of Geophysical Research: Space Physics volume 127 issue 1. 10.1029/2021JA029774