On the abundances of ultraheavy cosmic rays

Recent data from the HEAO 3 and Ariel 6 satellites on elemental abundances of ultraheavy cosmic rays (Z in the range from 33 to 83) are analyzed using a new propagation code. General agreement with earlier analyses is observed. Evidence for a breakdown of the correlation between ionization potentials and the solar system/cosmic-ray source abundance ratio is presented. It is found that the best fit to experimental data (approximately 5 GeV per nucleon) occurs when propagation is calculated at lower energies (approximately 1 GeV per nucleon). This is interpreted as evidence for distributed acceleration of cosmic rays. Additional effects, including ionization loss, altered path-length distributions, and r-process enhancement, are considered.