Solar wind heavy ions from flare-heated coronal plasma

Information concerning the coronal expansion is carried by solar wind heavy ions. Distinctly different energy-per-charge ion spectra are found in two classes of solar wind having the low kinetic temperatures necessary for E/q resolution of the ion species. Heavy ion spectra which can be resolved are most frequently observed in the low-speed interstream (IS) plasma found between high speed streams; the streams are thought to be coming from coronal holes. Although the sources of the IS plasma are uncertain, the heavy ion spectra found there contain identifiable peaks of O, Si and Fe ions. Such spectra indicate that the IS ionization state of O is established in coronal gas at T approximately 2.1 X 106K while that of Fe is frozen in farther out at approximately 1.5 X 106K. On occasion anomalous spectra are found outside IS flows in solar wind with abnormally depressed local kinetic temperatures. The anomalous spectra contain Fe16+ ions, not usually found in IS flows, and the derived coronal freezing in temperatures are significantly higher. The coronal sources of some of these ionizationally hot flows are identified as solar flares. (Auth.)