wherein said magnetic circuit comprises {TAIL ~ a magnetic field induction circuit} formed as {HEAD ~ a thin film} of the same superconducting material that is contained within said gap 
wherein said magnetic circuit comprises { TAIL ~ a magnetic field induction circuit } formed as { HEAD ~ a thin film } of the same superconducting material that is contained within said gap
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH