A flux pump for NMR magnets

A flux pump coupled to a slightly dissipative NMR magnet enables the magnet to operate effectively in persistent mode. This paper presents: 1) design and operation concept of the flux pump; 2) parameters and performance results of a prototype flux pump; and 3) a plan to couple a full-scale flux pump to two NMR magnets, one comprised of low- and high-temperature (LTS/HTS) superconducting coils in which the HTS insert is dissipative and the other an all-LTS which can be artificially made resistive. Performance results of the prototype coupled, sequentially, to two Nb-Ti magnets show that agreement between analysis and experiment is excellent.