Formation and Rearragement of Vortex Tubes in a 3D Mesoscopic Superconductor with a Central Weak Link

Vortex patterns are determined for a three-dimensional mesoscopic superconductor with one central weak link, using the time-dependent Ginzburg-Landau equations. The vortex states are obtained for field orientation parallel and perpendicular to the weak link, and vortex rearrangements are found to occur in the vortex patterns. Tilting of the field leads to interesting phenomena caused by the small volume-to-surface ratio, as vortex tubes are preferentially oriented along the field direction while they are forced to be perpendicular to the surface. In addition, we can also observe the intersection of vortex tubes inside (or near) the weak link.