The low-energy cosmic-ray nuclei and their propagation in interstellar space

Abstract

The differential energy spectra of the cosmic-ray nuclei helium, carbon, nitrogen, and oxygen above 30 MeV/nucleon, boron, neon, magnesium, and silicon above 50 MeV/nucleon, and the iron group above 100 MeV/nucleon, measured in October–December 1964 and May–June 1965 by the University of Chicago charged-particle telescope on board the OGO-I satellite (Comstock et al. 1966b), have been corrected to take account of the effective depletion depth of the gold–silicon solid-state detectors used for rate-of-energy-loss measurement. Additional data from October to December 1965 are included. The magnitudes and relative shapes of the spectra deduced by extrapolation to nearby interstellar space place important constraints on the allowed modes of interstellar propagation for these nuclei. Two-component models are shown to account for most of the observed properties of the interstellar cosmic-ray nuclei.