HR: 1330h
AN: P32A-1067    [PDF]
TI: Solar Wind Interaction With Martian Exosphere and Atmosphere: Charge Exchange, ENAs and the Loss of Planetary Ions
AU: * Kallio, E
EM: Esa.Kallio@fmi.fi
AF: Finnish Meteorological Institute, Geophysical Research, Vuorikatu 15A P.O. BOX 503, Helsinki, FIN-00101 Finland
AU: Janhunen, P
EM: Pekka.Janhunen@fmi.fi
AF: Finnish Meteorological Institute, Geophysical Research, Vuorikatu 15A P.O. BOX 503, Helsinki, FIN-00101 Finland
AB: Neither Mars nor Venus has a strong global intrinsic magnetic field and therefore the solar wind can flow close to the planets in high neutral density regions. Because of the formed direct interaction between the atmosphere/exosphere and the solar wind, the ionized atmospheric neutrals can be picked up by the solar wind. Charge exchange between solar wind protons and planetary neutrals, instead, produce energetic neutral hydrogen atoms (H-ENA) which are the manifestation of the direct interaction between the solar wind and planetary neutrals. Picked-up planetary O$^+$ ions in turn form energetic neutral oxygen atoms (O-ENA) via charge exchange process. The ion escape, H-ENAs, O-ENAs and electrons will soon be investigated at Mars(2004) and Venus(2006) by two identical instruments: ASPERA-3 on MarsExpress and ASPERA-4 on VenusExpress. We present a self-consistent, three-dimensional quasi-neutral hybrid (ions are particles, electrons a fluid) simulation to study Mars/Venus-solar wind interaction in general and ASPERA-3/4 measurements in particular. Our recently improved Mars model includes three ion species (H$^+$, O$^+$, O$_2^+$), and contains charge exchange, ion-neutral and chemical reactions. We show results of quasi-neutral hybrid model runs that we have used to study the escape of planetary ions, the effects of planetary ions on the Martian plasma environment and the production and properties of fast hydrogen(H) and oxygen(O) ENAs near Mars. The potential of the developed model to interpret forthcoming ASPERA-3 and 4 measurement are finally discussed.
DE: 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707)
DE: 2152 Pickup ions
DE: 2753 Numerical modeling
DE: 2780 Solar wind interactions with unmagnetized bodies
DE: 5435 Ionospheres (2459)
SC: Planetary Sciences [P]
MN: 2003 Fall Meeting