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Three-dimensional Configuration of Induced Magnetic Fields around Mars
  • +12
  • Chi Zhang,
  • Zhaojin Rong,
  • Lucy Klinger,
  • Hans Nilsson,
  • Zhen Shi,
  • Fei He,
  • Jiawei Gao,
  • Xinzhou Li,
  • Yoshifumi Futaana,
  • Robin Ramstad,
  • Xiao-Dong Wang,
  • Mats Holmström,
  • Stas Barabash,
  • Kai Fan,
  • Yong Wei
Chi Zhang
Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences
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Zhaojin Rong
Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences

Corresponding Author:[email protected]

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Lucy Klinger
Beijing International Center for Mathematical Research,Peking University, China
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Hans Nilsson
Swedish Institute of Space Physics
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Zhen Shi
IGGCAS
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Fei He
Institute of Geology and Geophysics, Chinese Academy of Sciences
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Jiawei Gao
GFZ German Research Center for Geosciences
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Xinzhou Li
Institute of Geology and Geophysics, Chinese Academy of Sciences
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Yoshifumi Futaana
Swedish Institute of Space Physics
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Robin Ramstad
University of Colorado Boulder
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Xiao-Dong Wang
Swedish Institute of Space Physics
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Mats Holmström
Swedish Institute of Space Physics
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Stas Barabash
Swedish Institute of Space Physics
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Kai Fan
Institute of Geology and Geophysics Chinese Academy of Sciences
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Yong Wei
Institute of Geology and Geophysics, Chinese Academy of Sciences
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Abstract

Using over 6 years of magnetic field data (2014.10-2020.12) collected by the Mars Atmosphere and Volatile EvolutioN (MAVEN), we conduct a statistical study on the three-dimensional average magnetic field structure around Mars. We find that this magnetic field structure conforms to the pattern typical of an induced magnetosphere, that is, the interplanetary magnetic field (IMF) which is carried by the solar wind and which drapes, piles up, slips around the planet, and eventually forms a tail in the wake. The draped field lines from both hemispheres along the direction of the solar wind electric field (E) are directed towards the nightside magnetic equatorial plane, which looks like they are “sinking” toward the wake. These “sinking” field lines from the +E-hemisphere (E pointing away from the plane) are more flared and dominant in the tail, while the field lines from the –E-hemisphere (E pointing towards) are more stretched and “pinched” towards the plasma sheet. Such highly “pinched” field lines even form a loop over the pole of the –E-hemisphere. The tail current sheet also shows an E-asymmetry: the sheet is thicker with a stronger tailward J×B force at +E-flank, but much thinner and with a weaker J×B (even turns sunward) at –E-flank. Additionally, we find that IMF Bx can induce a kink-like field structure at the boundary layer; the field strength is globally enhanced and the field lines flare less during high dynamic pressure; however, the rotation of the planet, against expectations, modulate the configuration of the tail current sheet insignificantly.