The Time Variations of the Cosmic Ray Intensity

Abstract

Time variations in the intensity of cosmic radiation arriving at the Earth's surface have been extensively studied over the last thirty years. Some of these variations are of atmospheric origin, but others are due to changing conditions in interplanetary space. It is reasonable to regard the solar system as being bombarded by an almost isotropic flux of energetic nuclei with energies ranging from 108 electron volts to 1019 electron volts. Particles in the range 108 eV to 1011 eV are modulated by the electromagnetic fields existing in interplanetary space so that a reduced intensity arrives at the Earth.