HR: 1340h
AN: P43A-0959    [Abstracts]
TI: Global Hybrid Simulations of the Corotating Plasma Interaction with the Neutral Environment of Titan (configuration of the TA flyby of Titan by Cassini)
AU: * Modolo, R
EM: Ronan.Modolo@cetp.ipsl.fr
AF: Swedish Institute of Space Physics, Uppsala Division Box 537, Uppsala, 751 21 Sweden
AU: Wahlund, J
EM: jwe@irfu.se
AF: Swedish Institute of Space Physics, Uppsala Division Box 537, Uppsala, 751 21 Sweden
AU: Chanteur, G M
EM: Gerard.Chanteur@cetp.ipsl.fr
AF: CETP - IPSL, 10-12, venue de l'Europe, Velizy, 78140 France
AB: The upper part of the atmosphere and the ionosphere of Titan interact directly with the corotating plasma of Saturn or with the solar wind depending upon its orbital phase and upon the dynamic pressure of the solar wind. We investigated the corotating plasma interaction with the exosphere of Titan with a three-dimensional and multi-species hybrid model taking into account self consistently the coupling between ionized and neutral species. In the hybrid approach, a fluid description for electrons and a fully kinetic description for ions is adopted . Since Larmor radii of incoming and pickup ions are large with respect to the radius of the atmospheric obstacle, a full description of ions dynamic is mandatory. Three neutral species (methane, molecular nitrogen and hydrogen) are assumed to described the Titan's exosphere. A spherical symetry is assumed and profile densities are derived from INMS observations. The neutral environment is partially ionized by solar photons, electron impacts, and charge exchange reactions between the incoming plasma and neutral species. The production rate are computed self-consistently from the neutral density and the ionization frequency or the cross-section. The corotating plasma is assumed to be made of O+ and H+ (thermal and energetic) ions while H2+, CH4+ and N2+ ions describe the planetary plasma. Simulations result are presented for the the TA flyby of Titan by spacecraft CASSINI on October 26th 2004. The submagnetosonic interaction of the kronian plasma with Titan is investigated, taking into account the different ram directions of the corotating plasma and solar radiation.
DE: 2423 Ionization processes (7823)
DE: 6281 Titan
DE: 6929 Ionospheric physics (1240, 2400)
SC: Planetary Sciences [P]
MN: Fall Meeting 2005