Indirect detection of cosmic rays

Abstract

Cosmic rays entering the Earth’s atmosphere interact with the nuclei of air and produce cascades of secondary particles. At high energy (E≳1014eV), these particle cascades are called extensive air showers and provide a means of measuring flux, arrival direction distribution, and elemental composition of cosmic rays. In this article, an introduction to the phenomenology of extensive air showers and parametrizations for their description is given. The concepts and key ideas of detecting extensive air showers are presented and methods for reconstructing the properties of the primary particles are discussed. Several representative experiments are reviewed to illustrate practical implementations of air shower detection concepts. The article concludes with a discussion of open problems and future detection techniques that are currently under development.