Evolution of the geoeffective April 5, 2010 CME in the inner heliosphere: A global MHD model with a data-constrained magnetic flux rope specification.

Modeling the evolution of internal magnetic structure of interplanetary coronal mass ejections (ICMEs) is important both for space weather prediction and for basic understanding of magnetized space plasma interactions. Data-driven modeling of ICMEs in the inner heliosphere (starting beyond the critical surface in the corona) presents an attractive and computationally feasible approach, since it bypasses the complex problem of CME initiation and eruption in the corona. Using this approach, we simulate the propagation of ICMEs through the inner heliosphere using a global model driven at the coronal boundary by the Wang-Sheeley-Arge (WSA)-ADAPT model. ICMEs are initiated at 20 solar radii (Rs) using a magnetohydrodynamic (MHD) analytical Gibson-Low (GL) model of a self-similarly expanding magnetic flux rope with parameters (e.g., location, geometry, speed, orientation) constrained by white-light coronograph observations. The ICME propagation is simulated using the Grid Agnostic MHD for Extended Research Applications (GAMERA) MHD model, which is a recent reinvention of the high-heritage Lyon-Fedder-Mobarry (LFM) code. We apply this approach to the study of a geoeffective ICME which arrived at Earth on April 5, 2010. This ICME appeared bright in SOHO/LASCO and STEREO coronagraphs allowing derivation of its parameters near the Sun thus constraining its properties in our model. However, the orientation of the flux rope was not determined uniquely from the observations. It was also not clear which part of the ICME hit Earth and caused the severe geomagnetic storm. By comparing synthetic white-light images derived from our MHD modeling with images from SOHO/LASCO and STEREO/HI1 and HI2, we shed light on the ICME initial orientation and it evolution due to the interaction with the background solar wind. We further compare the modeling results with ACE observations at 1 AU and discuss which part of the CME was probed by the spacecraft.