Solar Coronal and Photospheric Abundances from Solar Energetic Particle Measurements

We find that the ionic charge-to-mass ratio (Q/M) is the principal organizing parameter for the fractionation of solar energetic particles (SEPs) by acceleration and propagation processes and for flare-to-flare variability. Unfractionated coronal abundances for 20 elements with 6 ≤ Z ≤ 30 are derived by applying a single-parameter Q/M-dependent correction to the average SEP abundances, and unfractionated photospheric abundances are obtained by applying an additional correction based on first ionization potential