COMPARISON OF DISTRIBUTED REACCELERATION AND LEAKY-BOX MODELS OF COSMIC-RAY ABUNDANCES (3-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-28)

A large collection of elemental and isotopic cosmic-ray data has been analyzed using the leaky-box transport model with and without reacceleration in the interstellar medium. Abundances of isotopes and elements with charges 3 less-than-or-equal-to Z less-than-or-equal-to 28 and energies 10 MeV nucleon-1 less-than-or-equal-to E less-than-or-equal-to 1 TeV nucleon-1 were explored. Our results demonstrate that reacceleration models make detailed and accurate predictions with the same number of parameters, or fewer, as standard leaky-box models. Ad hoc fitting parameters in the standard model are replaced by astrophysically significant reacceleration parameters. Distributed reacceleration models explain the peak in secondary-to-primary ratios around 1 GeV nucleon-1. They diminish the discrepancy between rigidity-dependent leakage and energy-independent anisotropy. They also offer the possibility of understanding isotopic anomalies at low energy (Silberberg et al. 1983).