Modeling Solar Wind Interaction with Mars through a Ten-ion-species Multifluid MHD Approach

The configurations of the Martian ionosphere and magnetosphere play a crucial role in the process of ion escape, given that the ionosphere serves as an important source of Martian ion escape and the magnetosphere is closely associated with the escape channels. In this study, we introduced a recently developed three-dimensional multifluid magnetohydrodynamic (MHD) model involving ten ionospheric ion species prevalent on Mars, Ar⁺, CO₂⁺, CO⁺, C⁺, N₂⁺, N⁺, NO⁺, O⁺, O₂⁺, and H⁺. We solved control equations for each species integrated with their self-consistent chemical reactions. The model successfully reproduced the large-scale structure of bow shock (BS), magnetic pile-up boundary (MPB), and induced magnetosphere consistent with observational statistical results. Benefiting from the consideration of more species and relevant chemical reactions, the model calculated ionospheric profiles are in good agreement with existing studies derived from observations. Moreover, the presence of the crustal magnetic field concentrated in the southern hemisphere of Mars tends to elevate the boundary position of MPB by tens to hundreds of kilometers and impact ion escape processes. Therefore, our model, by calculating ion density and velocity for individual species, can reveal diverse effects of the crustal magnetic field on each ion species.