Chapter

Geology and Habitability of Terrestrial Planets

Volume 24 of the series Space Sciences Series of ISSI pp 279-300

Planetary Magnetic Dynamo Effect on Atmospheric Protection of Early Earth and Mars

  • V. DehantAffiliated withRoyal Observatory of Belgium Email author 
  • , H. LammerAffiliated withSpace Research Institute, Austrian Academy of Sciences
  • , Y. N. KulikovAffiliated withPolar Geophysical Institute (PGI), Russian Academy of Sciences
  • , J. -M. GrießmeierAffiliated withObservatoire de Paris
  • , D. BreuerAffiliated withDLR
  • , O. VerhoevenAffiliated withRoyal Observatory of Belgium
  • , Ö. KaratekinAffiliated withRoyal Observatory of Belgium
  • , T. Van HoolstAffiliated withRoyal Observatory of Belgium
  • , O. KorablevAffiliated withSpace Research Institute
    • , P. LognonnéAffiliated withInstitut de Physique du Globe de Paris

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Abstract

In light of assessing the habitability of Mars, we examine the impact of the magnetic field on the atmosphere. When there is a magnetic field, the atmosphere is protected from erosion by solar wind. The magnetic field ensures the maintenance of a dense atmosphere, necessary for liquid water to exist on the surface of Mars. We also examine the impact of the rotation of Mars on the magnetic field. When the magnetic field of Mars ceased to exist (about 4 Gyr ago), atmospheric escape induced by solar wind began. We consider scenarios which could ultimately lead to a decrease of atmospheric pressure to the presently observed value of 7 mbar: a much weaker early martian magnetic field, a late onset of the dynamo, and high erosion rates of a denser early atmosphere.

Keywords

Habitability Rotation Magnetic field Atmospheric escape