chapter  22
60 Pages

Superconducting Devices

ByV.L. Newhouse

A high-field superconductor may be considered as a type II superconductor containing inhomogeneities sufficiently coarse to act as pinning sites for flux moving through it. Ductile high-field superconductors are found among the alloys of niobium with titanium and zirconium. In the case of a high-field superconductor, most of this consists of forcing flux past pinning sites, a process which results in heat dissipation in the material. Experimentally, it is found that as the current through a high-field superconductor is increased, flux enters in abrupt increments. Superconducting coils are being introduced into many special applications: to obtain maximum stability, superconducting coils used in nuclear magnetic resonance (NMR) are usually short-circuited and High-field superconducting coils have been suggested for energy storage, particularly in space where weight is at a premium. In addition to supplying dc for superconducting magnets, superconducting generators may be attractive for generating room-temperature power in applications such as space flight where a very low weight per unit power is required.