COMPARISON OF DISTRIBUTED REACCELERATION AND LEAKY-BOX MODELS OF COSMIC-RAY ABUNDANCES -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 reaccele ration 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 e nergies 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 reacceler ation models make detailed and accurate predictions with the same numb er of parameters, or fewer, as standard leaky-box models. Ad hoc fitti ng parameters in the standard model are replaced by astrophysically si gnificant 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 an d energy-independent anisotropy. They also offer the possibility of un derstanding isotopic anomalies at low energy (Silberberg et al. 1983).