Expanshion of coronal mass ejections in the SOHO / LASCO field of view: some regularities

Regularities are examined of expansion of coronal mass ejections (CME) associated with limb eruptive prominences and/or posteruptive arcades in the SOHO/LASCO C2 and C3 field of view. As shown, such CMEs can be classified into two groups. CMEs of the first group are those for which their angle sizes in latitude 2α in the plane of the sky are unchangeable within the observational accuracy. The second group includes CMEs for which their angle sizes increase up to ejection front position RF = Rαm and are maximal (2αm) at this distance. It has been found that CMEs of second type are wider on average, faster and have denser outer sheath at large distances. On average, Rαm is shown to increase with 2αm.