New Measurements of Solar Particle Events Enriched in Heavy Ions

Abstract

The four most heavy-ion-rich of the nine largest solar energetic particle events detected by the Solar Isotope Spectrometer on the ACE, are the focus of this paper. We have used isotopic measurements of Ne to determine the degree of charge/mass fractionation and infer the charge states of C - Ni in these events. The results indicate a source temperature of ~ 4 x 10^6 K; this and the measured abundances suggest that these four events more similar to impulsive events than gradual. Although the ^3He/^4He ratios are not enhanced to the level typical of impulsive events, there are measurable enhancements over typical solar wind values in three of the events.