Diffusion of electrons and ions in a plasma across a magnetic field with the interplay of an anisotropic dynamical friction is formulated in terms of the methods of Brownian motion. For a special symmetry of the dynamical friction matrix it is found that for Larmor periods of the order of the relaxation time across the magnetic field the diffusion takes place as an ordinary Brownian motion uninhibited by the external magnetic field.

• Received 19 April 1963

DOI:https://doi.org/10.1103/PhysRev.132.21