Global Disturbances in the Mars Ionosphere and Magnetosphere During the 10 September 2017 Solar Flare Event: A Time-Dependent MHD Study

Solar flares produce a burst of radiation over a wide range of wavelengths including X-ray and extreme ultraviolet (EUV), resulting in important ionization and heating of planetary atmospheres. However, due to the lack of concurrent and multi-point observations, our knowledge of how and to what extent the near-Mars space environment responds to such episodic transient events is sparse. In particular, there is a critical gap in our understanding of whether and how flare-induced dayside ionospheric enhancements could propagate to the nightside and upward into the magnetosphere. In this study, we apply a global time-dependent MHD model to simulate spatial and temporal responses of the ionosphere and magnetosphere to a X8.2-class solar flare event on 10 September 2017, which represents one of the most powerful solar flare eruptions hitting Mars. The solar irradiance spectra and the upper atmospheric distributions during the flare event, which are needed for the MHD modeling, are adopted from Fang et al. [2019] using an ad-hoc spectral irradiance model with combined MAVEN and Earth measurements and the Mars Global Ionosphere-Thermosphere Model (MGITM), respectively. By performing the self-consistent simulations of neutral and plasma regimes, we report the first attempt to quantify the global flare impact in the ionosphere and magnetosphere and to characterize the time scales underlying the variabilities of various components of the near-Mars space environment. The potential impact of the solar flare event on atmospheric loss is also evaluated.