Authors: Shannon C. Hill (Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA), Matti Ala-Lahti (Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA), Tuija I. Pulkkinen (Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA), Austin Brenner (Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA), and Emilia K. J. Kilpua (Department of Physics, University of Helsinki, Helsinki, Finland)

We investigate the impacts of an ICME shock on 15 May 2005 via comparison of spacecraft and ground-based observations and SWMF Geospace simulation results. ACE, Wind, and Cluster observations reveal strong spatial variability of embedded magnetic structures within the 15 May 2005 ICME sheath. During the ICME sheath passage, IMAGE spacecraft observations show the development of a theta aurora in the southern polar cap. We use the University of Michigan’s Space Weather Modeling Framework in the Geospace configuration to analyze the interaction between the ICME sheath and the bow shock/magnetosphere and the impacts on the high-latitude ionosphere. We drive the event simulation with solar wind observations from the Wind spacecraft and compare simulation results to observed global indices. We analyze the 2D simulation cuts of the bow shock and magnetopause and compare the temporal dynamics to the observations. We also compare SuperMAG data to the simulated ionospheric electrodynamics in the high latitude regions to study the dayside and nightside responses to the ICME sheath shock and transmission into the magnetosphere. We discuss the importance of solar wind monitor choice when modeling solar wind-magnetosphere interactions.