Observations and modeling of an explosive coronal mass ejection as observed by LASCO

We present a qualitative and quantitative comparison of a single coronal ma ss ejection (CME) as observed by LASCO on 5 October 1996 with the results o f a two-dimensional magnetohydrodynamic (MHD) model. This event was selecte d as a clear example of a CME that is not caused by the disruption of a hel met streamer. This CME occurs against the background of multiple bright str eamers on the west limb. The CME is first seen as a brightening of the enti re west limb. The CME has a bright, sharp front that moves outward with no significant change in shape. The CME moves outward with roughly constant ve locity that is approximately twice as fast at high latitude as near the str eamer. The measured CME mass is 1.2x10(16) g. There are two parts to the MH D model. The pre-event corona was calculated using a 2-dimensional bi-modal model. The CME is simulated using a time dependent perturbation at the bas e of the corona. The model successfully reproduces the observed morphology, velocity profiles, and change in coronal mass. The observed velocity asymm etry is a natural consequence of the structure of the pre-event corona. Ani mations have been generated from both the data and model to illustrate the good agreement between the observations and simulation. These animations ca n be found on the CD-ROM which accompanies this volume.