Unusual isotopic composition of solar energetic particles observed in the November 6, 1997 event

Using the Solar Isotope Spectrometer on the Advanced Composition Explorer, we have measured the isotopic composition of solar energetic particles (SEP s) with energies of tens of MeV/nucleon during the November 6, 1997 solar e vent, including isotopes never before reported in SEPs, such as S-34, Ar-38 , Ca-44, Fe-54, and Ni-60, as well as isotopes of C, N, O, Ne, Mg, and Si. Abundances are found to be enhanced,by factors of similar to 2 relative to the standard solar system values for Ne-22/Ne-20 and Mg-26/Mg-24. Overall, the enrichments of the isotope ratios show a correlation with the ratio of masses, M-2/M-1, scaling approximately as (M-2/M-1)(7), although significan t deviations from this trend are evident.