In situ observation of filament plasma and their magnetic structure

Many CMEs, when observed during their expansion in the corona, are associated with a three-part structure: A bright core associated with prominence plasma, a dark area or cavity, that is bounded by a bright rim, presumably associated with the dynamic interactions of CMEs with their plasma environment. Many Interplanetary CMEs (ICMEs) only have two key parts: A magnetically dominated inner part, generally associated with the low density volume appearing dark in the corona, and the interaction sheath, presumably associated with the interaction of magnetic clouds in the corona. The vast majority of ICME do not have recognizable filament plasma. There are a few observations of ICMEs with singly charged He contributions that are generally associated with filaments. However, there are two model scenarios for producing such low ionic charge states. First, they can be achieved through filament-like material that never heats up during the eruption. Second, they can result from a rapid freeze-in process at high density in the corona. We discuss in situ observations of ICMEs that are characterized by unusually cool material and the ionic composition of all observable constituents that allow us to distinguish between these models. We discuss these data and interpret them in the context of CME models and the evolution of CMEs in the inner corona. We will also discuss the relation of the filament material to the magnetically dominated structures, such as flux ropes.