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[14.02] Mars Ion Loss Rates from a Global Hybrid Model of the Solar Wind Interaction

S.H. Brecht (Bay Area Reseach Corp.), S.A. Ledvina, J.G. Luhmann (Space Sci. Lab., Univ. of California, Berkeley)

One of the outstanding questions of Martian aeronomy is the loss rate of atmospheric ions to the solar wind. The outer atmosphere is exposed to the solar wind convection electric field and thus it is expected, and confirmed by observations, that Mars loses its outer ionosphere due to ion pickup. The importance of this loss process relative to other loss processes is however undetermined. For example, oxygen is lost by photochemical escape and pickup ion sputtering in addition to direct ion pickup. The absolute and relative rates are further variable since they are determined by solar extreme ultraviolet flux as well as solar wind parameters. Using global hybrid simulations of the solar wind interaction with Mars, including an oxygen ionosphere and exosphere, we investigate the dependence of the pickup ion loss rate on solar EUV and solar wind conditions including the interplanetary magnetic field direction. Consideration is given to what the ASPERA-3 ion spectrometer on Mars Express might detect when it arrives next year.

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.