A Study on the Acceleration of Coronal Mass Ejections

We present a statistical study on the acceleration of CMEs. This study is based on 23 CME events best observed by SOHO LASCO/C1 coronagraph, which observes the inner corona from 1.1 to 3.0 R_S. The kinematic evolution of a CME has a distinct acceleration phase that mainly takes place in the inner corona. We find that the acceleration duration distribution ranges from 10 to 1100 min with a median (average) value at 54 min (169 min). The acceleration magnitude distribution ranges from 6 m s^-2 to 947 m s^-2 with a median (average) value at 209 m s^-2 (280 m s^-2). We also find a good correlation between CME acceleration magnitude A (in unit of m s^-2) and acceleration duration T (in unit of min), which can be simply described as A=10000/T.