Plasma-particle interaction for strong stochastic magnetic fields: Isotropic and anisotropic scattering regimes

We investigate theoretically the interaction between charged particles and a plasma by calculating the scattering anisotropy. In several physical environments such as supernova shells, we expect strong stochastic magnetic fields. As shown, particle scattering is anisotropic in real physical situations even if the stochastic magnetic fields are isotropic and much stronger than the mean magnetic field. This anisotropic scattering result is very important for understanding diffusive shock acceleration, a mechanism which is usually thought to be responsible for the high energies of cosmic rays.