HR: 0800h
AN: SA31B-02    [Abstracts]
TI: 2D Numerical Study of Superthermal Particles in Martian Exosphere
AU: * Valeille, A
EM: arnaud@umich.edu
AF: University of Michigan, Space Research Building University of Michigan 2455 Hayward St., Ann Arbor, MI 48109-2143, United States
AU: Tenishev, V
EM: vtenishe@umich.edu
AF: University of Michigan, Space Research Building University of Michigan 2455 Hayward St., Ann Arbor, MI 48109-2143, United States
AU: Bougher, S W
EM: bougher@umich.edu
AF: University of Michigan, Space Research Building University of Michigan 2455 Hayward St., Ann Arbor, MI 48109-2143, United States
AU: Combi, M R
EM: mcombi@umich.edu
AF: University of Michigan, Space Research Building University of Michigan 2455 Hayward St., Ann Arbor, MI 48109-2143, United States
AU: Nagy, A F
EM: anagy@umich.edu
AF: University of Michigan, Space Research Building University of Michigan 2455 Hayward St., Ann Arbor, MI 48109-2143, United States
AB: Hot atomic oxygen two-dimensional velocity distributions, atmospheric loss rates and profiles of density and temperature have been calculated for Mars exosphere by using our new Direct Simulation Monte Carlo (DSMC) flow solver on an unstructured 2D-axisymmetric mesh. As a test of the 2D version of our code, the result of the 1D distribution function obtained by a two-stream transport model by Nagy et al. [J. Geophys. Res.,106, 21565, 2001.] was used as boundary condition. For the full 2D Solar Zenith Angle (SZA) dependent run however, a more complete approach was adopted and the 2D average of the well-established 3D thermospheric model of Bougher et al. [Geophys. Res. Lett., 33, doi:10.1029/2005GL024059, 2006.] has been used to calculate the production of hot O and its collisional thermalization with the dominant background species (O and CO2). Dissociative recombination (DR) of O2+ ions was assumed to be the main production of hot O and calculations were performed for equinox conditions and for both low and high solar activity cases. Due to the methodology of the DSMC method, the velocity distribution at the exobase describes the gas system of the Martian exosphere and allows us to provide a complete set of its macroscopic parameters.
DE: 5400 PLANETARY SCIENCES: SOLID SURFACE PLANETS
SC: SPA-Aeronomy [SA]
MN: 2007 Joint Assembly