Solutions of the Cosmic Ray Equation of Transport

The steady-state interplanetary propagation of solar cosmic rays is analyzed on the basis of the analytic solutions of Gleeson and Webb (1973) applied to the spherically symmetric, steady-state transport equation of cosmic rays. The cosmic rays are released monoenergetically at a constant rate from a spherical surface of fixed heliocentric radius, and redistribute in energy as they propagate. It is shown that particles of lower momentum lose a larger fraction of their initial momentum, and that the momentum spectra of the mean distribution function, of the particle number density per unit momentum interval, and of particle streaming are primarily determined by the radial dependence of the diffusion coefficient.