The expansion of a coronal mass ejection within LASCO field of view: some regularities

Forty five limb CMEs related with eruptive prominences and/or near-to-limb post-eruptive arcades have been tested. It is shown that CMEs can be divided into two groups. The first group includes coronal mass ejections whose "2 alpha" latitude angular sizes apparent in the plane of the sky remain unchanged within measurement accuracy of several degrees. The second one is formed by CMEs that expand "non-radially", namely, their angular sizes increase by the relative value (10-30)% up to the position of the ejection front R-F = R-alpha m and run to the maximal value 2 alpha(m) at this distance. It, has been found that CMEs of the second type are, on the average, wider, faster and have an outer shell brighter and with higher plasma density for long distances. It is shown that on average R alpha(m) increases as 2 alpha(m) rises.