Analysis of Interplanetary Coronal Mass Ejection Parameters as a Function of Energetics, Source Location, and Magnetic Structure

Abstract

We describe a study of how ICME parameters vary as function of source location, associated flare magnitude, and magnetic structure. The strongest compositional enhancements are found to occur in events originating in central longitudes of the Sun, those with large associated flares, and those that are identified as magnetic clouds. In situ velocity is highest for events associated with large flares. Density has a strong negative correlation with associated flare size, but no strong trend with source longitude or magnetic cloud structure. Temperature is lower than expected for events originating in central longitudes, events associated with large flares, and for magnetic clouds. Total magnetic field is highest for events originating in central longitudes and for magnetic clouds. Combining these results, we suggest that ICMEs may have a basic structure consisting of a core (or cores) of magnetic cloud plasma and compositional signatures that are modulated by CME energetics, surrounded by an envelope with weaker signatures. If this core/envelope scenario is proven to be valid, that suggests that a larger percentage of energetic ICMEs may contain enhanced composition that is not detected by the current single track observations.