Diffusion of charged particles in a large-scale stochastic magnetic field

The diffusion of magnetized charged particles, considered as test particles, in a turbulent plasma is analyzed. It is assumed that there is a regular, quasiuniform magnetic field BO in the plasma. There are also large-scale stochastic fluctuations of the field, B, and of the velocity of the medium, u, which satisfy the MHD equations. The length scales of the velocity and field fluctuations are greater than the local transport mean free path of the test particles. The drift kinetic equation for the particle distribution function is averaged over an ensemble of realizations of statistically uniform and isotropic fluctuations of the magnetic field and the velocity of the medium. No upper limit is imposed on the amplitudes. A renormalization method is used to calculate the average diffusion tensor. This method leads to a system of transcendental equations for the components of the diffusion tensor. These equations can be studied analytically and numerically. Some simple analytic expressions are derived to describe the various regimes of the particle diffusion across the regular magnetic field