Numerical Simulation of a "Stealth" CME: Why Slow and Simple is Not Mysterious

The stereoscopic viewing and improvements in coronagraph observations by STEREO/SECCHI and low corona EUV and X-ray observations at multiple wavelengths by STEREO, Hinode, and SDO -- combined with this solar minimum's exceptionally low activity -- have given rise to the community's interest in so-called "stealth" CMEs. A "stealth" CME is one in which there are almost no low coronal signatures of the CME eruption but often a very well resolved slow, flux-rope like eruption seen in the coronagraph data. The fact that the in situ observations of "stealth" CMEs have shown many of the signatures of magnetic clouds (including the interplanetary flux rope structure) poses the question, "Just how different these events are from normal CMEs?" We present a 3D numerical MHD simulation of the 2008 Jun 2 gradual streamer blowout CME which had virtually no identifiable low coronal signatures. We energize the field by simple footpoint shearing along the source region's polarity inversion line (PIL) and model the background solar wind structure using an ~2MK isothermal wind and a low-order PFSS representation of the CR2070 synoptic magnetogram. Our results will show that the CME "initiation" is obtained by slowly disrupting the quasi-steady-state configuration of the helmet streamer, resulting in the standard eruptive flare picture (albeit, on a large scale) that ejects the sheared fields and lowers the magnetic energy stored in filament channel. We obtain a relatively slow CME eruption and argue that these "stealth" CMEs are no different than the standard quasi-2D picture but are simply at the low end of the CME energy distribution. We will show preliminary comparisons between the simulation results and the coronagraph observations of the low coronal evolution of the CME.