Fine structure in the cosmic ray spectrum: Further analysis and the next step

TL;DR

This paper analyzes the fine structure of the cosmic ray spectrum, confirming spectral features and discussing potential mechanisms, while highlighting the limited contribution of a few sources to the helium peak at the knee.

Contribution

It provides a detailed analysis of spectral features in cosmic rays, confirming curvature and structure across multiple experiments and discussing possible origins.

Findings

Less than 10% of the helium peak at 5 PeV is from a few sources.

Confirmed concavity in proton and helium spectra at about 200 GV.

Identified 'ankles' in heavier nuclei spectra at hundreds of GeV/nucleon.

Abstract

An analysis is made of the fine structure in the cosmic ray energy spectrum: new facets of present observations and their interpretation and the next step. It is argued that less than about 10% of the intensity of the helium `peak' at the knee at $\simeq 5PeV$ is due to just a few sources (SNR) other than the single source. The apparent concavity in the rigidity spectra of protons and helium nuclei which have maximum curvature at about 200 GV is confirmed by a joint analysis of the PAMELA, CREAM and ATIC experiments. The spectra of heavier nuclei also show remarkable structure in the form of `ankles' at several hundred GeV/nucleon. Possible mechanisms are discussed. The search for `pulsar peaks' has not yet proved successful.