Energy Spectra of Abundant Nuclei of Primary Cosmic Rays from the Data of ATIC-2 Experiment: Final Results

TL;DR

This paper presents final results from the ATIC-2 balloon experiment, detailing energy spectra of various cosmic ray nuclei, revealing differences between proton and helium spectra, and showing complex energy dependence of cosmic ray composition.

Contribution

It provides improved methods and higher resolution data for cosmic ray energy spectra, confirming previous preliminary findings and revealing new spectral features.

Findings

Proton spectrum is steeper than helium spectrum.

Spectra of protons and heavier nuclei are non-power law.

Complex energy dependence of cosmic ray composition is observed.

Abstract

The final results of processing the data from the balloon-born experiment ATIC-2 (Antarctica, 2002-2003) for the energy spectra of protons and He, C, O, Ne, Mg, Si, and Fe nuclei, the spectrum of all particles, and the mean logarithm of atomic weight of primary cosmic rays as a function of energy are presented. The final results are based on improvement of the methods used earlier, in particular, considerably increased resolution of the charge spectrum. The preliminary conclusions on the significant difference in the spectra of protons and helium nuclei (the proton spectrum is steeper) and the non-power character of the spectra of protons and heavier nuclei (flattening of carbon spectrum at energies above 10 TeV) are confirmed. A complex structure of the energy dependence of the mean logarithm of atomic weight is found.