  We present results from extensive simulations of driven vortex lattices
interacting with periodic arrays of pinning sites. Changing an applied driving
force produces a rich variety of novel dynamical plastic flow phases which are
very distinct from those observed in systems with random pinning arrays.
Signatures of the transition between these different dynamical phases include
sudden jumps in the current-voltage curves as well as marked changes in the
vortex trajectories and the vortex lattice order. Several dynamical phase
diagrams are obtained as a function of commensurability, pinning strength, and
spatial order of the pinning sites.

Superconductivity