Characterizing Interplanetary Coronal Mass Ejections Using In Situ Observations of Solar Wind Heavy Ions

Enhancements in certain high charge states of Fe, C and O have been shown to occur throughout Interplanetary Coronal Mass Ejections (ICMEs). The presence of these ions is a result of increased ionization attributed to enhanced heating at the Sun during the initiation and release of ICMEs. Using in situ ICME observations from 1998-2011 by the Solar Wind Ion Composition Spectrometer (SWICS) on the Advanced Composition Explorer (ACE) spacecraft at L1 we analyze the variation in the ratios of heavy ion charge states compared with published ICME databases from Cane and Richardson and Jian et al. We test which ensemble of charge state ratios at which thresholds correlates best with ICME observations using Heidke Skill Scores and Receiver Operating Characteristic (ROC) curves. We examine how these ratios vary with ICME features such as a clear flux rope signature, and the shock.