Solar Coronal and Photospheric Abundances from Solar Energetic Particle Measurements

Solar energetic particle (SEP) elemental abundance data from the Cosmic Ray Subsystem (CRS) aboard the Voyager 1 and 2 spacecraft (Breneman and Stone 1985} are used to derive unfractionated coronal and photospheric abundances for elements with 3 < Z < 30. We find that the ionic charge-to-mass ratio (Q/M) is the principal organizing parameter tor the fractionation of SEPs by acceleration and propagation processes and for fl.are-to-fl.are variability, making possible a single parameter Q/M-dependent correction to the average SEP abundances to obtain unfractionated coronal abundances. A further correction based on first ionization potential allows the determination of unfractionated photospheric abundances.