Chapter 2 - Cosmic rays in the Atmosphere

Abstract

This chapter discusses cosmic rays in the atmosphere. It includes the data and results of cosmic ray experiments carried out at altitudes higher than sea level. Measurements performed on the ground at mountain levels, covering altitudes between a few hundred meters and 6500meters above sea level along with the results of aircraft and balloon-borne experiments that cover essentially the entire atmosphere to its very fringes of just 2 or 3 g/cm2 of residual atmosphere. The high altitude data is also the backbone for the determination of the primary cosmic ray spectrum and mass composition over a wide range of energies that are complemented in the low energy domain by satellite measurements, and air shower data at high and ultra high energies. In respect to the rapidly falling intensity of the cosmic radiation with increasing energy and because of the limited size and duration of aircraft and balloon-borne experiments, the statistics of the data, particularly at higher energies and for the less abundant components of the radiation, are subject to poor statistics. Nevertheless, till date, a large number of experiments had been carried out, and a remarkable stock of cosmic ray data from all levels in the atmosphere has become available over the years is discussed in this chapter.