Stochastic vs. kinetic approach in the theory of anomalous transport in plasmas

The anomalous diffusion coefficient in a turbulent plasma with destroyed magnetic surfaces can be introduced in two ways. The first one starts from a stochastic Langevin equation from which the mean square displacement of a test particle is calculated. The second one is based on a kinetic equation from which the correlation function of fluctuating quantities is computed. The two approaches are critically compared.