Authors: Wraback, E. M. (University of Michigan), Landi, E. (University of Michigan), Manchester, W.B. (University of Michigan), Szente, J. (Boston University)
The ionization state of plasmas leaving the Sun freezes in low in the solar corona and carries information about the inner corona through the heliosphere, which in situ measurements can extract to study early solar wind and coronal mass ejection (CME) evolution and energetics. 3D global magnetohydrodynamics models allow us to link the measured in-situ charge states to the energetics in the inner corona, where many processes driving the evolution occur. In this work, we use the Alfvén Wave Solar atmosphere Model (AWSoM) to simulate the April 9th, 2008, CME (aka “Cartwheel CME”). We study the energy budget evolution in the CME as the non-equilibrium charge states freeze-in, to understand what is driving the plasmas’ evolution through the solar corona. Early in the eruption, a significant portion of the magnetic energy stored in the flux rope dissipates to thermal energy or is converted to kinetic energy. The CME-driven compression increases the density at the CME front, in turn increasing the Alfvén wave reflection rate, which goes into heating the front. The enhanced temperature and density at the CME-driven front increase the ionization efficiency, causing the average Fe charge state to be about 12, which persists to the edge of the simulation domain at 24 Rs. The backside and legs of the CME are heated by reconnection as the CME detaches from the Sun, forming a current sheet and increasing the plasma ionization in localized regions. The prominence material remains cold, due to continued radiative cooling of the material, with especially low average Fe charge states (3-5) out to 10 Rs.