Modeling Extreme Space Weather Scenarios: July 23, 2012 Rare-Type CME

Space weather is a major concern for modern day society because of its adverse impacts on technological infrastructure such as power grids, oil pipelines, and global navigation systems. Particularly, earth directed coronal mass ejections (CMEs) are the main drivers of the most extreme geomagnetic storms in the near-Earth space environment. On 23 July 2012, NASA's Solar Terrestrial Relations Observatory-Ahead (STEREO-A) spacecraft observed in situ an extremely fast CME that traveled 0.96 astronomical units (~1 AU) in about 19 h. In our study, we use the Space Weather Modeling Framework (SWMF), a 3-D MHD based code, to perform simulations of this rare CME by considering STEREO-A in situ observations to represent the upstream L1 solar wind boundary conditions. The goal of the study is to investigate what would have happened if this Rare-type CME was Earth-bound. Global SWMF-generated ground geomagnetic field perturbations are used to compute the simulated induced geoelectric field at specific ground-based active magnetometer sites. Simulation results show that the July 23 CME would have produced ground effects comparable to previously observed extreme geomagnetic storms such as the Halloween 2003 storm. In addition, we discuss how this study compares to other independent studies on this same event.