Troubles in Mars Ionosphere Modeling

Abstract

AbstractThe Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft has acquired comprehensive measurements of the properties that determine the density and composition of the ionosphere of Mars, namely solar irradiance, thermospheric density and composition, and electron temperature. Ionospheric models that use these measured properties as inputs ought, in principle, to accurately reproduce corresponding MAVEN measurements of ionospheric density and composition. Here we test whether or not several Mars ionosphere models do so. We focus on the optically thin portion of the photochemical equilibrium region of the dayside ionosphere, 160–200 km altitude, where ionospheric modeling is most straight‐forward. The predictions of Fox et al. (2021, https://doi.org/10.1016/j.icarus.2020.114186) clearly delivered better model‐data agreement than the other models considered herein, although the model of Mayyasi et al. (2019, https://doi.org/10.1029/2019ja026481) also performed well. For the other models assessed herein, model‐data discrepancies in ion densities of at least a factor of two were present in at least one major ion species.