Evolution of CME-driven Shocks in the Lower Corona for the October-November 2003 Events

While it is generally accepted that the largest energetic particle events are created by CME-driven shocks in interplanetary space, the relative importance of CME-driven shocks versus flare-related processes in creating energetic particles low in the corona is not understood and is an area of active research. We analyzed the formation of CME driven shocks in the lower corona for the Halloween Space Storms that occurred in late October and early November 2003. We used the Space Weather Modeling Framework (SWMF) developed at the University of Michigan to create a realistic corona. The CME was modeled as an out of equilibrium flux rope lying under a closed field region in the AR 10486. The MHD code was first used to create realistic background corona using observed photospheric fields for boundary conditions for the Carrington rotation 2008. The background corona was validated by comparing results from the model with in situ solar wind observations from ACE/WIND. We discuss the magnetosonic speed profile in the lower corona and the consequences for the CME shock formation. Consequences for the acceleration of particles to GeV/nucleon are discussed. The computational runs were performed at the supercomputer Columbia at NASA/AMES.