Measurements of the Heavy - Ion Elemental and Isotopic Composition in Large Solar Particle Events from ACE
نویسندگان
چکیده
Using the Solar Isotope Spectrometer (SIS) on the Advanced Composition Explorer (ACE), we have measured the isotopic composition of as many as eleven elements from He through Ni at energies of tens of MeV /nucleon in eleven solar energetic particle (SEP) events that have occurred since November 1997. We find that isotopic composition varies dramatically from event to event. For example, the 22Nej20 Ne ratio ranges from "' 0. 7 to > 2 times the solar wind value, being lowest for iron-poor events and highest for iron-rich events. We present the SIS SEP isotope measurements to date and show that the strong correlation of elemental and isotopic abundance ratios suggests that elemental and isotopic fractionation are governed by the same process.
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