  In this paper we discuss the results of some Molecular Dynamics simulations
of a magnetized One Component Plasma, targeted to estimate the diffusion
coefficient $D_{\perp}$ in the plane orthogonal to the magnetic field lines. We
find that there exists a threshold with respect to the magnetic field strength
$|\vec B|$: for weak magnetic field the diffusion coefficients scales as
$1/|\vec B|^2$, while a slower decay appears at high field strength. The
relation of this transition with the different mixing properties of the
microscopic dynamics is investigated by looking at the behavior of the velocity
auto correlation.
