Effects of physical features in the solar atmosphere on the coronal mass ejection evolution

Based on time-dependent MHD simulation, we investigate how physical features in the solar atmosphere affect the evolution of coronal mass ejections (CMEs). It is found that temperature and density play a crucial role in CME initiation. We argue that lower temperature facilitates the catastrophe's occurrence, and that the CMEs which initiate in low density could gain lower velocity. In our numerical experiment, by employing different values of ß, the resulting eruptions of either slow or fast events may be obtained.