Formation, Propagation, and Decay of Coherent Pulses of Solar Cosmic Rays

We have performed numerical simulations of the interplanetary transport of solar cosmic rays. The particles form a coherent pulse within $\sim 0.01$ AU after their injection. The gradual decrease of a pulse’s speed and anisotropy can be understood in terms of an equilibrium between pitch-angle scattering and focusing. The results should be useful for estimating times of particle injection.