A magnetohydrodynamic modelling approach to simulate CME-forced planetary magnetospheres and predict geomagnetic impacts

Coronal Mass Ejections (CMEs) carry large amounts of magnetized plasma into the heliosphere at very high speeds. Their interplanetary counterparts, or Interplanetary CMEs (ICMEs), create adverse space weather conditions around planets. These interplanetary structures have the potential to cause hazardous space weather and impact space- and ground-based technologies on Earth. At CESSI we have developed a 3D magnetohydrodynamic STORM Interaction (CESSI-STORMI) module to simulate the interactions between ICMEs and planets with and without a global magnetosphere. In this talk, I shall discuss our data-driven simulations to assess ICME impact on the Earth’s magnetosphere and  present a methodology to estimate their geo-effectiveness. We validate this module with observations and find a good match with the observed values of the Dst index for past events. In addition, we also present a qualitative study of the global magnetosphere under the influence of ICMEs. Our work allows us to estimate the severity of geomagnetic storms based on early, data-driven inputs of ICME flux rope profiles gleaned from near-Sun or in-situ observations. Thus our work has the potential to significantly extend the time window for predicting the severity of geomagnetic storms - which remains a grand challenge in heliophysics.