Atmospheric Effects of Solar Energetic Particle Events In Magnetized and Non-Magnetized Regions of Mars

Solar and shock-accelerated heliospheric energetic charged particles represent an important if irregular source of energy to the Martian upper atmosphere. A Monte Carlo code has been developed to track a population of protons in an atmosphere and account for energy loss to collisional processes including heating, ionization, excitation, and charge transfer. The model framework is open to multiple planetary-specific inputs (e.g. three-dimensional neutral densities, electric and magnetic fields) and uses an adaptive trace algorithm to accurately model collisions in dense and sparse atmospheric regions. Applying 3-D models of electric and magnetic fields from the Michigan Mars MHD code and 1-D neutral densities from the Mars Global Thermosphere Ionosphere Model (M-GITM), we use this model to calculate volume rates of relevant proton-mediated energy loss processes in the Martian upper atmosphere. The model will be improved to generate ionization and heating rates in areas of strong and weak crustal magnetic fields for solar energetic particle events observed by the SEP instrument on MAVEN. Ultimately this will form part of a comprehensive model of solar wind interactions with Mars.