| 摘要 |
A magnetic shield of superconducting material is positioned in the vicinity of a superconductive winding having current flowing therethrough. When the shield is in a superconductive condition, the magnetic lines of force produced by the winding are forced into a longer path than without the shield, so that the magnetic field within the winding is smaller than the lowest critical field intensity at any point of the winding. When the current in the winding reaches a predetermined intensity, the shield loses its shielding effect at least partially, due to the increased magnetic field, so that the magnetic lines of force are shortened and the magnetic field increases within the winding to a magnitude above the highest critical magnetic field intensity at any point of the winding passed by the predetermined current. |
