Geomagnetic effects on anisotropic cosmic radiation

Abstract

Two different methods are discussed for taking geomagnetic effects into account when evaluating the counting rate of a cosmic‐ray detector for a given anisotropic radiation source. The applicability of these methods is studied, and some properties of the asymptotic cone of acceptance are found by performing the transformation through the geomagnetic dipole field of the infinitely small solid‐angle elements that constitute the acceptance cone. A solid angle at the detector is greater than the corresponding asymptotic cone for all latitudes, angles of incidence, and energies except immediately above the geomagnetic cutoff. This focusing effect is especially good for high‐latitude detectors, which thus have the best resolving power.