Solar-stellar outer atmospheres and energetic particles, and galactic cosmic rays

Abstract

The heavy element compositions of the solar corona, solar wind (SW), solar energetic particles (SEPs), and galactic cosmic ray sources (GCRSs) all exhibit the same pattern when compared to standard local galactic composition; the pattern involves an underabundance of heavy elements with first ionization potential (FIP) greater than about 9 eV relative to elements with lower FIP by factors of about 4-6. The similar abundance patterns found in SW, SEP, and GCRS suggest that they were all extracted from solar stellar coronae, with their compositions reflecting, to first order, that of their birthplace. GCRSs are presently interpreted in terms of a two-step acceleration scenario in which most should be MeV-stellar energetic particles first injected by flares out of the coronae of unevolved, later-type stars, which were subsequently reaccelerated to high energy by strong interstellar shock waves.