Pitch angle distribution of solar flare particles in interplanetary space

Abstract

During the initial anisotropic phase of solar particle events, the flux in the radial direction is considerably less than that from the garden hose field direction. An analysis based on the theory of charged particle transport in random magnetic fields has been conducted to determine the pitch angle distribution of particles with respect to the garden hose field lines. With the commonly observed magnetic field power spectral density functions, the model reveals that the flux is proportional to cos δ, where δ represents the angular separation from the garden hose direction. This theoretical result is verified by the analysis of relativistic solar particle observations during the appropriate anisotropic phases of several otherwise dissimilar ground level events; i.e., those of May 4, 1960; November 12, 1960; November 18, 1968; and February 25, 1969.