# The cosmic-ray spectrum in the PeV to EeV energy range

## TL;DR

This paper reviews recent experimental findings on the energy spectrum and composition of cosmic rays from PeV to EeV energies, shedding light on their origins, acceleration, and the transition from galactic to extragalactic sources.

## Contribution

It provides an overview of recent experimental results on cosmic-ray spectrum and composition in the PeV to EeV range, highlighting progress in understanding their origins and propagation.

## Key findings

- Recent measurements clarify the spectrum shape around the knee.
- Composition data suggest a transition from galactic to extragalactic sources.
- Experimental results support models of cosmic-ray acceleration mechanisms.

## Abstract

Cosmic rays around the so-called knee in the spectrum at around PeV primary energy are generally galactic in origin. Observations on the form of their energy spectrum and their mass composition are fundamental tools to understand the origin, acceleration and propagation mechanism of high-energy cosmic rays. In addition, it is required to find signatures to clarify the transition from galactic to extragalactic sources, which are believed to be responsible for the highest-energy cosmic rays above EeV. This brief review focuses on recent experimental results around the knee of the all-particle energy spectrum and composition in the energy range of the knee up to EeV energies.