Shock wave effects in solar cosmic ray events

Two low-energy ( 1 MeV) solar proton events which display a gradual intensity increase to a maximum near the time of an SSC, followed by an abrupt, large decrease, are interpreted in terms of a population of cosmic rays which are swept ahead of an interplanetary shock wave. A model which describes the variation with time of intensity and anisotropy at the Earth is developed using a Monte Carlo technique which traces the histories of particles released impulsively at the Sun. A good fit to each of the profiles observed at 0.6 to 0.9 MeV proton energies is obtained with a diffusion coefficient 2 × 10²⁰ cm² s^–) = 13.46 - 2.99 sin²1 and a near perfect shock reflector.Now at University of California, LASL, Los Alamos, New Mexico.