Three-dimensional, multifluid, high spatial resolution MHD model studies of the solar wind interaction with Mars

Our newly developed 3-D, multifluid MHD model is used to study the interaction of the solar wind with Mars. This model is based on the BATS-R-US code, using a spherical grid and a radial resolution equal to 10 km in the ionospheric regions. We solve separate continuity, momentum, and energy equations for each ion fluid and run our model for both solar minimum and maximum conditions. We obtain asymmetric densities, velocities, and magnetic pileup in the plane containing both the direction of the solar wind and the convective electric field. These asymmetries are the result of the decoupling of the individual ions; therefore, our model is able to account for the respective dynamics of the ions and to show new physical processes that could not be observed by the single-fluid model. Our results are consistent with the measured bow shock and magnetic pileup locations and with the Viking-observed ion densities. We also compute the escape fluxes for both solar minimum and solar maximum conditions and compare them to the single-fluid results and the observed values from Mars Express.