Active and eruptive prominences and their relationship to coronal mass ejections

In order to understand better the dynamical processes in the solar atmosphere that are associated with coronal mass ejections (CMEs), we have carried out a study of prominence activity using H alpha observations obtained at the Mauna Loa Solar Observatory (MLSO). After developing clear definitions of active prominences (APs) and eruptive prominences (EPs), we examined 54 H alpha events to identify distinguishing characteristics of APs and EPs and to study the relationship between prominence activity and CMEs. The principal characteristics we found to distinguish clearly between APs and EPs are maximum projected radial height, projected radial velocity, and projected radial acceleration. We determined CME associations with H alpha events by using white-light data from the Mk III K-Coronameter at MLSO and the LASCO C2 Coronagraph on SOHO. We found that EPs are more strongly associated with CMEs than are APs and that the CMEs associated with EPs generally have cores, while those associated with APs do not. A majority of the EPs in the study exhibit separation of escaping material from the bulk of the prominence-the latter initially lifting away from and then returning toward the solar surface. This separation tends to occur in the height range from 1.20 to 1.35 R-0, and we infer that it involves the formation of an X-type neutral line in this region, which allows disconnection of part of the prominence material. This disconnection view of prominence eruption seems most consistent with flux rope models of prominence support.