36th DPS Meeting, 8-12 November 2004
Session 34 Comets: Nuclei, Tails, Solar Wind
Poster II, Thursday, November 11, 2004, 4:15-7:00pm, Exhibition Hall 1A

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[34.09] Multi-fluid MHD Cometary Atmosphere Simulation for Halley-type Comets.

M. Benna, P. R. Mahaffy (NASA- Goddard Space Flight Center)

We present new results of our Cometary Atmosphere Simulation (CASIM) code that is presently under development to model the interaction of a cometary atmosphere with the solar wind. Several high-resolution 2-D simulations for a Halley-type comet are shown.

In the current simulations we investigate more precisely the evolution of the interaction between the cometary atmosphere and the solar wind starting from the early stages of the comet outgassing (~5. a.u.) to the peak of its activity (~1.5 a.u.). Our code is based on the solution of the multi-fluid MHD equations using an efficient adaptively refined cartesian mesh solver that provides a very high resolution over a large space domain (simulation domain ~ 108 km, highest resolution ~ 25 m).

The multi-fluid approach we chose leads to a more accurate representation of the cometary atmosphere since additional details of the interaction between the neutral gas and the plasma, and their resulting structures are revealed. In particular, the multi-fluid representation of the ion population gives an improved view of the coupling between heavy and light ions and the resulting coma boundaries at different spatial scales.

This research is sponsored by NASA and the National Academies.

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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.