Spatiotemporal dynamics and plastic flow of vortices in superconductors with periodic arrays of pinning sites

We present simulations of flux-gradient-driven superconducting rigid vortices interacting with square and triangular arrays of columnar pinning sites in an increasing external magnetic field. These simulations allow us to quantitatively relate spatiotemporal microscopic information of the vortex lattice with typically measured macroscopic quantities, such as the magnetization {ital M}({ital H}). The flux lattice does not become completely commensurate with the pinning sites throughout the sample at the magnetization matching peaks, but forms a commensurate lattice in a region close to the edge of the sample. Matching fields related to unstable vortex configurations do not produce peaks in {ital M}({ital H}). We observe a variety of evolving complex flux profiles, including flat terraces or plateaus separated by winding current-carrying strings and, near the peaks in {ital M}({ital H}), plateaus only in certain regions, which move through the sample as the field increases. Several short videos, illustrating several particular cases of the type of dynamics described here, are available at http://www-personal.engin.umich.edu/--nori. {copyright} {ital 1996 The American Physical Society.}