A complete model of the propagation of solar-flare cosmic rays

A two-stage model of the propagation of 1-50 MeV solar-flare cosmic rays is presented. The first stage consists of a thin spherical shell of radius rsub(a) near the Sun which feeds particles into interplanetary space (the second stage) where they propagate along the Archimedean mean interplanetary magnetic field under the influences of anisotropic diffusion, convection, and energy changes. To calculate the time dependence at a fixed point in space, account is taken of the corotation of flux tubes past the observer. It is shown that the well-known east-west effect of the time-to-maximum cannot be obtained if the injection from the first stage is impulsive and thus a time and longitude dependent release for the second stage is essential. This is achieved by treating the first stage as a thin, spherical, diffusing shell of radius rsub(a) with diffusion coefficient kappasub(s), from which particles leak into interplanetary space at a rate determined by the leakage coefficient eta. (Auth.)