Comparison of CMEs, magnetic clouds, and bidirectionally streaming proton events in the heliosphere using helios data

Abstract

Coronal Mass Ejections (CMEs) are large, energetic expulsions of mass and magnetic fields from the Sun; they can significantly affect large volumes of the heliosphere and appear to be a key cause of geomagnetic storms. We have compiled a list of all significant CMEs detected by the HELIOS white light photometers from 1975–1982. We are studying the characteristics of these CMEs, and present preliminary results of their associations with in-situ features, especially magnetic “clouds” and periods of bidirectionally streaming ions, two classes of structures considered indicative of interplanetary loops. Advantages of this data set include reliable association in the interplanetary medium of the white light CME plasma with the in-situ features, and observations of a large number of events over a long time base.