Observable Properties of the Breakout Model for Coronal Mass Ejections

We compare the ‘‘magnetic breakout’’ model for coronal mass ejections (CMEs) with observed general properties of CMEs by analyzing in detail recent high-resolution MHD simulations of a complete breakout CME. The model produces an eruption with a three-part plasma density structure that shows a bright circular rim outlining a dark central cavity in synthetic coronagraphic images of total brightness. The model also yields heighttime profiles similar to most three-part CMEs, but the eruption speed by 2.5 R is of order the Alfvén speed, indicative of a fast CME. We show that the evolution of the posteruptive flare loop and chromospheric ribbons determined from the model are in agreement with observations of long-duration flares, and we propose an explanation for the long-standing observation that flares have an impulsive and gradual phase. A helical magnetic flux rope is generated during eruption and is consistent with a large class of interplanetary CME observations. The magnetic fields in this flux rope are well approximated by the Lundquist solution when the ejecta are at 15 R and beyond. Furthermore, the interior density structure of the magnetic flux rope appears to have some of the basic features of an ‘‘average’’ magnetic cloud profile at 1 AU. Future simulation improvements and more stringent observational tests are discussed. Subject headinggs: MHD — Sun: corona — Sun: coronal mass ejections (CMEs) — Sun: magnetic fields