http://arxiv.org/abs/1903.06330
Galactic cosmic-ray source compositions (Z/H)GCRS, measured from H to Pb and ~10^8-10^14 eV, differ greatly compared to solar system (Z/H)SS by factors of ~20-200. Yet these two compositions are drawn from essentially the same core collapse (CCSN) and thermonuclear (SN Ia) supernova ejecta: (Z/H)SS from unbiased accumulation over ~Gyr and (Z/H)GCRS from highly biased sampling during the brief period <30 kyr of homologous early Sedov-Taylor supernova expansion that diffusive shock acceleration (DSA) is most effective. These differences reveal how (Z/H)GCRS can result from just two self-consistent processes: ubiquitous mass mixing (Z/H)SS/(Z/H)CCSN ~4 of shocked, swept-up interstellar medium with high metallicity, core collapse supernova ejecta forming a base; and selective grain injection of refractory elements first condensed FGC as fast grains in freely expanding ejecta, then Coulomb-sputtered FCS by H and He as suprathermal ions into supernova shocks, where DSA carries them to cosmic-ray energies. This bulk mixing selectively increases source mix abundances (Z/H)SM /(Z/H)SS by ~2-10; and injection by grain condensation fractions FGC, from meteoritic chondrules, further enhances by ~6, while elemental-charge Z^2/3-Coulomb grain sputtering and scattering yields FCS give added enrichment of ~4-20. Applying these basic processes of mixing and injection to solar system (chondrule) abundances (Z/H)SS produces grain-injected, source-mix (Z/H)SMGI that match major cosmic-ray abundances (Z/H)GCRS to 1+-35% with no free parameters. Independently confirming the power of grain injection, (Z/H)GCRS shows no detectable contribution of Fe from SN Ia, which produce ~1/2 Fe in ISM, which is quite consistent with no dust in SN Ia remnants, unlike CCSN.
R. Lingenfelter
Mon, 18 Mar 19
72/102
Comments: 41 pages, 10 figures
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