Cosmic Rays in the 'Knee'-Region - Recent Results from KASCADE -

TL;DR

The KASCADE experiment's recent findings reveal a knee-like feature in cosmic ray spectra, with a shift from light to heavy primaries at higher energies, providing insights into cosmic ray origins and acceleration models.

Contribution

This study presents detailed energy spectra of cosmic ray mass groups using advanced unfolding techniques, confirming the knee structure and comparing results with interaction models.

Findings

Knee-like structure observed in light primary spectra.

Heavy primaries dominate at higher energies.

Data constrains models of cosmic ray acceleration and propagation.

Abstract

Recent results from the KASCADE experiment on measurements of cosmic rays in the energy range of the knee are presented. Emphasis is placed on energy spectra of individual mass groups as obtained from sophisticated unfolding procedures applied to the reconstructed electron and truncated muon numbers of EAS. The data show a knee-like structure in the energy spectra of light primaries (p, He, C) and an increasing dominance of heavy ones (A>20) towards higher energies. This basic result is robust against uncertainties of the applied interaction models QGSJET and SIBYLL. Slight differences observed between experimental data and EAS simulations provide important clues for improvements of the interaction models. The data are complemented by new limits on global anisotropies in the arrival directions of CRs and by upper limits on point sources. Astrophysical implications for discriminating models of maximum acceleration energy vs galactic diffusion/drift models of the knee are discussed based on this data. To improve the reconstruction quality and statistics around 10^17 eV, KASCADE has recently been extended by a factor 10 in area. The status and expected performance of the new experiment KASCADE-Grande is presented.