Structures in the cosmic ray energy spectra

Abstract

All the components of cosmic rays have 'structure' in their energy spectra at some level, ie deviations from a simple power law, and their examination is relevant to the origin of the particles. Emphasis, here, is placed on the large-scale structures in the spectra of nuclei (the 'knee' at about 3 PeV), that of electrons and positrons (a shallow 'upturn' at about 100 GeV) and the positron to electron plus positron ratio (an upturn starting at about 5 GeV). Fine structure is defined as deviations from the smooth spectra which already allow for the large-scale structure. Search for the fine structure has been performed in the precise data on positron to electron plus positron ratio measured by the AMS-02 experiment. Although no fine structure is indicated, it could in fact be present at the few percent level.

8 pages, 2 figures, accepted for publication in Astroparticle Physics

References in corpus (8)

• Observation of an anomalous positron abundance in the cosmic radiation
• The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
• Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01
• Pulsars versus Dark Matter Interpretation of ATIC/PAMELA
• Wavelet Analysis on Solar Wind Parameters and Geomagnetic Indices
• Possible structure in the cosmic ray electron spectrum measured by the ATIC-2 and ATIC-4 experiments
• Electrons and Positrons in Cosmic Rays
• Cosmic ray positrons from a local, middle-aged supernova remnant