Computer simulation of cosmic ray trajectories in near earth space

Abstract

The dynamics of cosmic ray ions of energy 10-100 MeV/N in and around the terrestrial magnetic field is studied using the method of trajectory tracing. The trajectory of a cosmic ray particle is back traced from the point of observation in the simulated magnetic field adopted by International Geomagnetic Reference Field (IGRF). The magnetic field used for this purpose is calculated from the magnetic potential described in the form of spherical harmonic multipole expansion of order 10 and degree 10. This represents only the static magnetic field to the sources internal to the earth. The purpose of the study is to investigate (1) the conditions of transmission of cosmic ray particles into the geomagnetic field and the statistical characteristics of the distribution of such ions near the earth's surface; (2) the sensitivity of the parameters involved in the trajectory computation, such as the ionization state, energy, arrival location, arrival direction etc