The ^3He-Rich SEP Events of August 2002: Exceptional Elemental and Isotopic Composition Patterns at Energies Above 10 MeV / Nucleon

Abstract

Heavy-ion composition observations from the Solar Isotope Spectrometer on ACE are reported for four ^3He-rich solar-energetic-particle (SEP) events that occurred in August 2002. The abundance enhancement patterns are not monotonic functions of atomic number (or mass), such as is commonly found in 3He-rich events, but have large enhancements of abundance ratios between some neighboring elements (e.g., N/O) and between isotopes of some elements (e.g., 26Mg/24Mg). The possibility that these patterns could be indicative resonant acceleration of particles within a narrow range of charge-to-mass ratios is considered.