Superconductors are materials that offer no electrical resistance when cooled below a certain temperature.
Apart from allowing the current to pass without resistance these materials are known to repel the magnetic field.
In a useful type of superconductor, however, the magnetic field passes through a narrow region around which super currents circulate.
This entity is called a vortex. The vortices are arranged in a regular pattern (Abrikosov Lattice).
Here the squeezing of the magnetic lines forces through the vortex assumes a shape of a wine glass.