Longitudinal magnetic field increases critical current in   superconducting strip
  The critical state of the vortex lattice in a thin strip is considered for the case when first a perpendicular magnetic field is applied, then a longitudinal field, and then again the perpendicular field is increased. This longitudinal field can strongly enhance the critical currents in the strip since the vortices are inclined and the currents flow in the strip plane. 
Ernst Helmut Brandt and Grigorii Mikitik