  Transport and acceleration of charged particles in turbulent media is a topic
of great interest in space physics and interstellar astrophysics. These
processes are dominated by the scattering of particles off magnetic
irregularities. The scattering process itself is usually described by
small-angle scattering with the pitch-angle coefficient $D_{\mu\mu}$ playing a
major role. Since the diffusion coefficient $D_{\mu\mu}$ can be determined
analytically only for the approximation of quasi-linear theory, the
determination of this coefficient from numerical simulations has, therefore,
become more important. So far these simulations yield particle tracks for
small-scale scattering, which can then be interpreted using the running
diffusion coefficients. This method has a limited range of validity. This paper
presents two new methods that allow for the calculation of the pitch-angle
diffusion coefficient from numerical simulations. These methods no longer
analyse particle trajectories, but the change of particle distribution
functions. It is shown that they provide better resolved results and allow for
the analysis of strong turbulence. The application of these methods to Monte
Carlo simulations of particle scattering and hybrid MHD-particle simulations is
presented. Both analysis methods are able to recover the diffusion coefficients
used as input for the Monte Carlo simulations and provide better results in MHD
simulations especially for stronger turbulence.
