Inter-Hemispheric Asymmetry (IHA) in the Magnetosphere-Ionosphere System Due to the December 04, 2021 Solar Eclipse: MHD-GCM Coupled Simulations

Solar eclipses present unique opportunities for investigating the Geospace environment. While the impact of rapidly changing solar radiation on Earth’s ionosphere-thermosphere (IT) is well studies, the effects of eclipses on magnetosphere-ionosphere (MI) coupling dynamics, particularly through alterations in ionospheric conductance, remain inadequately explored. Moreover, the abrupt and substantial changes during eclipses may induce notable inter-hemispheric asymmetry (IHA) in the MI system. A total solar eclipse occurred over western Antarctica from 06 to 09 UT on December 04, 2021. In this study, a new eclipse mask model will be used to specify the EUV irradiation for driving the Global Ionosphere-Thermosphere Model (GITM), with NCAR electrodynamo module as the global electrodynamic driver. For comparison, two runs are conducted with or without the eclipse mask. Subsequently, by feeding GITM simulated ionospheric conductivity from the two runs back to the BATS-R-US Magnetohydrodynamics (MHD) model, the impacts of the eclipse will be further assessed. The study lies on the three aspects: 1) Validating simulation through data-model comparisons regarding the eclipse response and IHAs in the MI system; 2) Assessing eclipse-induced depletion of ionospheric conductivity and its impacts on the magnetosphere. 3) Investigating the eclipse feedback from magnetosphere to the ionosphere such as the response time. Our study will help quantify the solar eclipse effects on the global MI system to shed new lights on magnetosphere-ionosphere-thermosphere studies under extraordinary solar conditions.