Magnetic Field Line Transport in the Heliosphere and Energetic Particle Propagation from Corotating Interaction Regions to High Heliographic Latitudes

Abstract

A numerical model of magnetic turbulence allows us to compute the diffusion coefficients for different degrees of anisotropy, and in particular for the cases corresponding to the solar wind. We consider here the problem of the propagation of the energetic particles accelerated by corotating interaction regions (CIRs) and observed by Ulysses at high heliographic latitudes. The excursion in latitude of a magnetic field line located at large heliospheric distance is evaluated with a Monte Carlo simulation. In the calculations, the random `force' terms are proportional to the square root of the diffusion coefficient in each direction. By tracing a large number of field lines, we can devise how the particles would be seen by Ulysses. Good agreement with the actual observations is found.