  Identifying the sources of the highest energy cosmic rays requires
understanding how they are deflected by the stochastic, spatially intermittent
intergalactic magnetic field. Here we report measurements of energetic
charged-particle propagation through a laser-produced magnetized plasma with
these properties. We characterize the diffusive transport of the particles
experimentally. The results show that the transport is diffusive and that, for
the regime of interest for the highest-energy cosmic rays, the diffusion
coefficient is unaffected by the spatial intermittency of the magnetic field.
