Parallel and perpendicular diffusion coefficients of energetic particles interacting with shear Alfven waves

We investigate the interaction of energetic particles with parallel propagating shear Alfven waves. We use analytical tools as well as test-particle simulations. The analytical derivation of the parallel diffusion coefficient is done by employing quasi-linear theory, a well-known tool in diffusion theory. The perpendicular diffusion coefficient, however, is derived by employing the unifield non-linear transport theory. This is the first time we derive a simple analytical form of the perpendicular mean free path based on the latter theory. We perform the simulations and we show that quasi-linear theory works well for parallel diffusion in Alfvenic slab turbulence as expected. We also show that the unified non-linear transport theory perfectly describes perpendicular diffusion for the turbulence model used here.