Solar Wind - Venus Interaction During the Solar Maximum & Solar Minimum Periods: A Newly Developed Multi-Fluid MHD Model

A three-dimensional, four-species multi-fluid magnetohydrodynamic (MHD) model was developed to simulate the global interaction between the solar wind and Venus during the solar maximum and solar minimum periods. The model was augmented to incorporate the production and loss of the significant ion species in the Venusian ionosphere, i. e. H⁺, O₂⁺, O⁺, CO₂⁺, taking into account chemical reactions among all species. Results of simulated Venusian induced magnetosphere, which were validated by comparing with the observations from Venus Express, suggest that the shock locations are closer to the planet during the solar minimum condition, because the magnitude of electromagnetic forces in the minimum increased to counterbalance the heightened solar wind dynamic pressure. The Venusian ionosphere simulation results show that the ionospheric density profile is more condensed during solar minimum which are consistent with previous observations and simulations. Moreover, by taking advantage of our model, functions of electromagnetic forces acting on various ion species were analyzed to explore potential mechanisms behind the differences between these two solar wind conditions. The estimated ions escape rate is much higher for the minimum condition due to increased J×B forces within the magnetotail which are cause by the compressed magnetic field lines under higher solar wind dynamic pressures. This multi-fluid MHD model could serve as an efficient tool for exploring the fine structures of the Venusian space environment system and could also find applications in the future study of distinguishing impacts caused by the variation of a single parameter.