Interplanetary signatures of solar mass ejections

Some manifestations of solar activity are able to release huge amounts of plasma into interplanetary space, which, in principle, can be distinguished from the normal solar wind. In an oversimplification of these processes, all the transient mass ejections of the Sun, as well as all kinds of transient material found in the interplanetary medium, have been called ''coronal mass ejections'' (CMEs). In this work we have selected three different transient interplanetary signatures observed in the solar wind at 1 AU, namely. magnetic clouds, helium enhancements and bidirectional electron and ion fluxes, and undertaken a correlative study with the corresponding solar observations in order to distinguish the solar origin of the differing signatures. We find that more than 90% of these signatures correspond to cases when a flare and/or the eruption of a prominence occurred near solar central meridian between 1 and 4 days before the observation of the disturbance at 1 AU, the highest association being with nares. We also find that although commonly different signatures appear in a single interplanetary transient event, they are not necessarily simultaneous, that is, they belong to different plasma regions within the ejecta. (C) 1997 COSPAR. Published by Elsevier Science Ltd.