Computer simulations of large cosmic ray showers using recent models of hadronic collisions

This thesis is concerned with the computer simulation of large cosmic ray showers. After a general introduction to cosmic rays and extensive air showers (EAS), a review of the nuclear physics and electromagnetic processes relevant to EAS studies is presented. The method of computer simulation of the hadronic core, electromagnetic cascade, muon component and atmospheric Cerenkov light component of cosmic ray showers is described in detail. Results of the present calculations using Feynman scaling for the momentum distribution of secondary particles in nuclear interactions are given for primary energies ranging from 10(^16) eV to 10(^18). A novel method of imaging the development of EAS by using information contained in the time structure of Cerenkov light pulses is described. Calculations of the response of experiments designed to detect the isotropic optical emission from EAS are also described, with particular reference to the detection of scattered Cerenkov light. The results of the present calculations are compared with a broad range of experimental data in an attempt to clarify the implications of the data for particle physics and for the primary mass composition at EAS energies.