Cosmic ray threshold rigidities and the earth's magnetic field

Abstract

Abstract Approximate corrections to the vertical threshold rigidities for cosmic rays in the earth's magnetic field are given, which take into account both the effects of the non-dipole part of the internal field and the penumbra. The thresholds obtained are tabulated every 2½° geographic latitude and every 5° geographic longitude. The accuracy of these thresholds is discussed and it is shown that they fit experimental data better than do previous approximations.