Numerical study of energetic particle parallel, perpendicular and energy diffusion and drift motion in interplanetary space

Evaluation of transport coefficients for energetic particles in the solar wind by analytical, theoretical means is difficult because root mean square field fluctuations are between about 1/3 and 1/2 the mean field value. Moreover, the wave motion contains a substantial proportion of finite amplitude, non-transverse Alfven disturbances, together with some longitudinal waves where /B/ changes. Following the statistical properties of particle trajectories in such a field is best done by numerical means. The problems addressed are the spatial and energy dependence of the parallel diffusion mean free path (derived from the pitch angle scattering coefficient), the energy dependence of the diffusion coefficients in energy space due to the interplanetary acceleration process and the modification to the guiding centre drift motion by scattering which may have implications for the conclusions concerning off-ecliptic modulation effects