Comparison of two coronal mass ejections observed by EIT and LASCO with a model of an erupting magnetic flux rope

We present observations of two coronal mass ejections (CMEs) observed by th e LASCO and EIT instruments on board the Solar and Heliospheric Observatory . One was observed on 1997 April 30 and the other on 1997 February 23. The latter CME is accompanied by a spectacular prominence eruption and reaches velocities of about 900 km s(-1), while the former has no apparent accompan ying prominence eruption and attains velocities of only about 300 km s(-1). However, the two CMEs are similar in appearance, having bright circular ri ms that can be interpreted as marking the apexes of expanding magnetic flux ropes, and both can be tracked from their origins near the surface of the Sun out to great distances. We compare the kinematic and morphological prop erties of these CMEs with an MHD model of an erupting flux rope and find th at the CMEs can be successfully modeled in this manner.