A Study on the Functional Characteristics of Superconducting Loops for External Magnetic Flux Suppression

The functional characteristics of superconducting loops passively driven by an external magnetic flux have been experimentally investigated. The loops can be used for external magnetic flux suppression in superconducting magnets which need to generate highly stable magnetic fields. Two one-turn-loops were installed between two superconducting coils which generate a strong magnetic field, and a Hall sensor and a search coil were set at the center of the system. The effect of external magnetic flux suppression of the one-turn-loops was measured while changing the strength of the magnetic field on the loops. Contrary to expectation, as the magnetic field strength on the loops increased, the suppression rate decreased. The reason for the degradation was identified as a micrometer-order wire motion caused by the electromagnetic force on the loops. Then, the loops were remade and ultra-tightly fixed, before testing again. This time no degradation was observed.