Solar Wind Heavy Ions from Energetic Coronal Events

摘要

Ions heavier than those of He can be resolved in the solar wind with electrostatic E/q analyzers when the local thermal temperatures are low. Ordinarily this condition prevails in the low speed solar wind found between high speed streams, i.e. the interstream, IS, solar wind. Various ions of O, Si and Fe are resolved in IS heavy ion spectra. Relative ion peak intensities indicate that the O ionization state is established in the IS coronal source regions at approx. 2.1 x 10 exp 6 K while the state of Fe is frozen in at approx. 1.5 x 10 exp 6 K farther out. Occasionally, anomalous spectra are observed in which the usually third most prominent ion peak, O exp 8+ , is depressed as are the Fe peaks ranging from Fe exp 12+ to Fe exp 7+ . A prominent peak in the usual Si exp 8+ position of IS spectra is self-consistently shown to be Fe exp 16+ . These features demonstrate that the ionization states were frozen in at higher than usual coronal temperatures. The source regions of these hot heavy ion spectra are identified as energetic coronal events including flares and nonflare coronal mass ejections. 24 references. (ERA citation 04:037634)