The Cosmic Ray Primary Spectrum in the Transition Region between Direct and Indirect Measurements (10 TeV–10 PeV)

Abstract

The cosmic ray primary spectrum between 10 TeV and 10 PeV is a key region to understand the origin and the acceleration processes of the galactic radiation. Around 100 TeV measurements performed by balloons and air shower arrays partially overlap. The experimental results recently obtained by both techniques are summarized. The picture that comes out from a common interpretation of the data is a steeper proton spectrum compared to the helium, CNO, and iron groups with a dominance of the helium component in the knee region. The agreement on the proton spectrum by balloons and air shower arrays is remarkable. The all particle spectrum obtained from the fit of the single mass groups reproduces fairly well the world average experimental all particle spectrum in the 10 TeV–10 PeV region.