  The mean square displacement and instantaneous diffusion coefficient for
different configurations of charged particles in stochastic motion are
calculated by numerically solving the associated equations of motion. The
method is suitable for obtaining accurate descriptions of diffusion in both
intermediate and long time regimes. It is also appropriate for studying a
variety of astrophysical configurations since it may incorporate microscopic
physics that analytical methods cannot cope with. The results show that, in the
intermediary time regime, the diffusion coefficient has an irregular behavior,
which can be described in terms of the complex interplay appearing between the
physical parameters describing the configuration. The main conclusion is that
such an approach may serve at differential diagnosis of different astrophysical
configurations.
