4-D modeling of CME expansion and EUV dimming observed with STEREO/EUVI

摘要

This is the first attempt to model the kinematics of a CME launchand the resulting EUV dimming quantitatively with a self-consistent model.Our 4-D-model assumes self-similar expansion of a spherical CME geometrythat consists of a CME front with density compression and a cavity withdensity rarefaction, satisfying mass conservation of the total CMEand swept-up corona. The model contains 14 free parameters and isfitted to the 25 March 2008 CME event observed withSTEREO/A and B. Our model is able to reproduce the observed CME expansionand related EUV dimming during the initial phase from 18:30 UTto 19:00 UT. The CME kinematics can be characterized by a constantacceleration (i.e., a constant magnetic driving force). While theobservations of EUVI/A are consistent with a spherical bubble geometry,we detect significant asymmetries and density inhomogeneities with EUVI/B.This new forward-modeling method demonstrates how the observed EUV dimmingcan be used to model physical parameters of the CME source region,the CME geometry, and CME kinematics.