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

Understand

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.