Response of the Martian environment to solar wind dynamic pressure change
Résumé
The main structures of the solar wind plasma interaction with the upper atmosphere can be usually described using a steady state picture, however time-dependent effects play important roles. In the last couple of years sophisticated 3D simulation try to address the response of the induced magnetosphere and its escape to different time-dependent drivers. Modolo et al (2012) discussed about timescales required for the induced magnetosphere to recover from an IMF rotation. Ma et al (2013) used time-varying solar wind conditions (density and velocity enhancement) and concluded that the ionospheric/atmospheric system reach a new equilibrium in few hours. We use a 3D parallel multi-species hybrid simulation model to study the response of the induced magnetosphere to a time-varying solar wind dynamic pressure. The hybrid model (Modolo et al, 2014, in prep) includes crustal fields, a ionospheric chemistry scheme and uses a 3D description of the Martian thermosphere (Chaufray et al, 2014) and exosphere (Yagi et al, 2012). The impact of a solar wind dynamic pressure change on plasma boundaries is discussed. A special attention is focused on the time-varying energy deposition in the upper atmosphere by O+ ions precipitation as well as the escape flux of planetary ions.