Superconducting flux pumps

Abstract

This paper presents a perspective on flux pumps. Flux pumps are a means of providing current to a coil or a magnet without direct electrical or physical contact. Typically, a coil would be charged directly using current leads, which would then be withdrawn if the magnets operated in the persistent mode (as with magnetic resonance imaging) or left in place if the field required maintenance or ramping. Flux pumps use the principle of magnetic induction. They present two distinct advantages. The first is that there is no direct connection to the external world and, therefore, no associated heat loss. The second is that, although high current can be developed in the magnet or the coil, these can be produced without the need for high-current power supplies, which are bulky and expensive. Flux pumps are especially appropriate for machines constructed from high temperature superconductors (HTSs). They facilitate the full use of the HTS's current carrying capability, cheaply and simply, enabling smaller, lighter, and more powerful magnets, motors, and generators.