American Geophysical Union, Journal of Geophysical Research, A12(106), p. 29231-29238, 2001
DOI: 10.1029/2001ja000014
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We present solar wind Fe charge state data measured on the Advanced Composition Explorer (ACE) from early 1998 to the middle of 2000. Average Fe charge states in the solar wind are typically around 9+ to 11+. However, deviations from these charge states occur, including intervals with a large fraction of Fe>=16+ which are consistently associated with Interplanetary Coronal Mass Ejections (ICMEs). By studying the Fe charge state distribution, we are able to extract coronal electron temperatures often exceeding 2 million Kelvin. We also discuss the temporal trends of these events, indicating the more frequent appearance of periods with high Fe charge states as solar activity increases.