Coronal Abundances of Neon and Magnesium Isotopes from Solar Energetic Particles

Abstract

The relative abundances of 22 to 70 Me V nucleon^(-l) Ne and Mg isotopes from two large flare-associated
\nsolar energetic particle (SEP) events in 1992 October and November, are determined from data taken by the
\nMass Spectrometer Telescope on the polar-orbiting SAMPEX satellite. After converting the measured abundances
\nto coronal values, the average ^(22)Ne/^(20)Ne ratio is 0.076 ± 0.008, consistent with the solar wind value of
\n0.073 but significantly less than that of previous SEP measurements, in which the abundance of ^(22)Ne was
\nsubstantially enhanced. The average ^(26)Mg/^(24)Mg ratio is 0.152 ± 0.012, consistent with both previous SEP and
\nother solar system measurements.