HR: 11:05h
AN: SA12A-04 INVITED     [Abstracts]
TI: Latest Results From ASPERA and Implications for Atmospheric Loss
AU: * Kallio, E
EM: Esa.Kallio@fmi.fi
AF: Esa Kallio, Finnish Meteorological Institute, Space Research, Vuorikatu 15A, Helsinki, FI-00101 Finland
AU: Team, A
EM: stas.barabash@irf.se
AF: ASPERA-3 Team, Swedish Institute of Space Physics, Kiruna, Box 803 Sweden
AB: Mars does not have 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 the 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 are currently measured at Mars by ASPERA-3 (Analyzer of Space Plasmas and Energetic Atoms) instrument onboard MarsExpress orbiter. The measurements started in January 2004. ASPERA-3 contains four individual subunits. Ions are measured by IMA (Ion Mass Analyzer), energetic neutral atoms by NPI (Neutral Particle Imager) and NPD (Neutral Particle Detector), and electrons by ELS (Electron Spectrometer) instruments. In this presentation we (1) Summarize some of the basic new measurements associated with Martian atmospheric loss made by ASPERA-3/MarsExpress instrument, and (2) Use global Mars-solar wind interaction models to interpret the measurements.
DE: 5407 Atmospheres--evolution
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2459 Planetary ionospheres (5435, 5729, 6026, 6027, 6028)
DE: 2481 Topside ionosphere
DE: 2780 Solar wind interactions with unmagnetized bodies
SC: SPA-Aeronomy [SA]
MN: 2004 AGU Fall Meeting