  Using molecular dynamics simulations we investigate the translational
dynamics of particles with dipolar interactions in homogenous external fields.
For a broad range of concentrations, we find that the anisotropic, yet normal
diffusive behavior characterizing weakly coupled systems becomes anomalous both
parallel and perpendicular to the field at sufficiently high dipolar coupling
and field strength. After the ballistic regime, chain formation first yields
cage-like motion in all directions, followed by transient, mixed
diffusive-superdiffusive behavior resulting from cooperative motion of the
chains. The enhanced dynamics disappears only at higher densities close to
crystallization.
