We present a numerical investigation of the coronal evolution of a coronal
mass ejection (CME) on 2005 August 22 using a 3-D thermodynamics
magnetohydrodynamic model, the SWMF. The source region of the eruption was
anemone active region (AR) 10798, which emerged inside a coronal hole. We
validate our modeled corona by producing synthetic extreme ultraviolet (EUV)
images, which we compare to EIT images. We initiate the CME with an
out-of-equilibrium flux rope with an orientation and chirality chosen in
agreement with observations of a H-alpha filament. During the eruption, one
footpoint of the flux rope reconnects with streamer magnetic field lines and
with open field lines from the adjacent coronal hole. It yields an eruption
which has a mix of closed and open twisted field lines due to interchange
reconnection and only one footpoint line-tied to the source region. Even with
the large-scale reconnection, we find no evidence of strong rotation of the CME
as it propagates. We study the CME deflection and find that the effect of the
Lorentz force is a deflection of the CME by about 3 deg/Rsun towards the East
during the first 30 minutes of the propagation. We also produce coronagraphic
and EUV images of the CME, which we compare with real images, identifying a
dimming region associated with the reconnection process. We discuss the
implication of our results for the arrival at Earth of CMEs originating from
the limb and for models to explain the presence of open field lines in magnetic
clouds.
