Solar Flare Effects in the Martian Ionosphere and Magnetosphere: 3-D Time-Dependent MHD-MGITM Simulation and Comparison With MAVEN and MGS

Abstract

A comprehensive modeling study has been conducted to investigate space weather effects at Mars during the 10 September 2017 solar flare, utilizing an integrated framework that combines the global magnetohydrodynamic (MHD) model and Mars Global Ionosphere-Thermosphere Model (MGITM). This is the first time the thermosphere-ionosphere-magnetosphere system is self-consistently simulated under realistic, time-varying conditions. Our simulations align well with observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN). Recognizing that complexities due to highly disturbed upstream conditions and rotating crustal fields obscure solar flare effects in orbit-to-orbit comparisons, we perform controlled simulations of nonflare and flare cases and exploit their contrast to quantify spatiotemporal variations in flare impact. Our results highlight pronounced and rapid dayside ionospheric perturbations, contrasting with weaker and delayed nightside responses. Notably, in the topside ionosphere, $O_2^{+}$ and C$O_2^{+}$ densities increase primarily on the dayside below $\sim$300 km altitude, peaking with an increase of 20%–30%. The $O^{+}$ density shows a more significant increase of up to $\sim$50%, extending into the magnetosphere and nightside via plasma transport, increasing its total loss rate by 14%. We observe distinct altitude-dependent patterns in dayside electron density enhancements in percent, characterized by a weakening with altitude and a rapid decay below $\sim$150 km in line with the flare development, and a gradual intensification between $\sim$150–300 km due to plasma transport and flare-induced atmospheric upwelling. Earlier Mars Global Surveyor observations were limited to the low-altitude pattern due to atmospheric expansion and missed the higher altitude variations observed by MAVEN.