3-DIMENSIONAL MHD SIMULATIONS OF THE INTERACTION BETWEEN VENUS AND THE SOLAR-WIND

We have developed a three-dimensional, single-fluid, MHD code which ha s successfully simulated the major qualitative features of the Venus - solar wind interaction. A bow shock forms at a height above the ionos phere close to that deduced from Pioneer Venus Orbiter (PVO) observati ons. The bow shock shows an asymmetry in the terminator plane qualitat ively similar to results obtained from PVO data analyses. The magnetic field drapes over the planet and forms a two-lobed magnetotail. The m agnetic field configuration near the planet is very similar to that re corded by PVO as well. We model the Venus obstacle as a hard, conducti ng sphere. We simulate the case in which the IMF is tilted with respec t to the incoming solar wind velocity at approximately the Parker spir al angle; this is the first simulation of this particular case which i ncludes all spatial regions of the interaction.