Modeling the Response of the Martian Upper Atmosphere to Solar Flares

Over the past decade, observations and models of Mars' atmosphere have enabled scientists to begin to focus not only on the climatology and global behavior of the atmosphere, but also on time-dependent behavior that extends over multiple spatial scales. The ability to study the effects of transient phenomena is not only important from a scientific perspective, but also from an operational one, since spacecraft are often asked to sample the atmosphere well below the exobase. Previous works have already begun to study the effects of solar flares on the ionosphere using observations (e.g. Mendillo et al., 2006; Mahajan et al, 2009). In this study, we utilize the recently developed and initially validated 3-D Mars Global Ionosphere-Thermopshere Model (M-GITM) to examine the effects of a large solar flare on the martian thermosphere and ionosphere. M-GITM simulates the atmosphere from the ground to exobase in spherical coordinates while relaxing the hydrostatic assumption and utilizing a terrain-following coordinate system. The model makes use of required physical processes, formulations, and subroutines that have been taken from existing lower and upper atmosphere Mars GCMs. In this study, we focus on the perturbation of the mass and electron densities caused by solar flares and examine the role that preconditioning plays in the response of the atmosphere.