Characteristics of the energy spectra of cosmic rays and a single source model

Abstract

As the accuracy of measuring the energy spectra of different nuclei in the primary cosmic ray flux and their ratios grows, more evidence appears for the nonpower character of these spectra at energies below the knee at 3–4 PeV. Irregularities in the spectra are the natural consequence of the nonuniformity of the cosmic ray source distributions: their types, ages and distances to the Earth; the nonuniformity of the interstellar medium; and the different densities, temperatures, and natures of magnetic fields. In particular, the flattening of the proton and helium energy spectra, the growth of the fraction of positrons in the total flux of positrons and electrons, and the constancy of the ratio of antiprotons to protons at sub-PeV energies could be due to the contribution from nearby and young sources emitting harder energy spectra of particles. It is shown that the recent measurements of the ratio of the boron and carbon nuclei performed in the AMS-02 experiment could also indicate that there is a contribution from a single comparatively young and nearby source.