Penetration of laterally quantized flux lamina into a superconducting wire network

We report direct, high resolution images of the magnetic field above a superconducting wire grid as applied flux penetrates into an initially empty state or into a state with half the plaquettes containing a magnetic quantum. We find two qualitatively different initial approaches to equilibrium: in wide structures for the former, or with long, linear structures for the latter case. In the approach to an empty state, we observe the formation of residual quasi-bound magnetic vortex/anti-vortex pairs.