4D-Modeling of CME Expansion and EUV Dimming Observed with STEREO/EUVI
Markus J. Aschwanden Submitted: 2009-06-08 11:24
This is the first attempt to model the kinematics of a CME launch
and the resulting EUV dimming quantitatively with a self-consistent model.
Our 4D-model assumes self-similar expansion of a spherical CME geometry
that consists of a CME front with density compression and a cavity with
density rarefaction, satisfying mass conservation of the total CME
and swept-up corona. The model contains 12 free parameters and is
fitted to the 2008 March 25, 18:30 UT, CME event observed with
STEREO/A and B. Our model is able reproduce the observed CME expansion
and related EUV dimming during the initial phase from 18:30 UT
to 19:00 UT. The CME kinematics can be characterized by a constant
acceleration (i.e., a constant magnetic driving force). While the
observations 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 dimming
can be used to model physical parameters of the CME source region,
the CME geometry, and CME kinematics.
Authors: Markus J. Aschwanden
Publication Status: Annales Geophysicae (accepted 2009-Aug-13, in press)
Last Modified: 2009-08-13 08:38