A Cabled-Wire Magnet Powered by a Flux Pump

Abstract

Superconducting magnets have developed at such a rapid pace that large-bore magnets generating fields up to 100 kG are now readily attainable. The recent trend is, however, away from magnets wound from a single wire or tape to multistrand cable and heavy strips containing many embedded wires. The critical current of the individual superconducting wires has also been increased by optimizing heat treatments and alloy compositions. As a result, the operating current level of this new generation of superconducting magnets, constructed of improved wire energized in parallel, has greatly increased. With the introduction of very large currents from outside the dewar to the magnet, heat dissipation and accompanying large helium losses become a major problem.