Macroscopic Magnetic Coupling Effect: The Physical Origination of a High-Temperature Superconducting Flux Pump

The high-temperature superconducting (HTS) flux pump, as a wireless superconducting dc power supply, would slash the cost of cryogenics for HTS magnets. This technology is held back, though, by our limited understanding of how ac magnetic-field stimulation induces superconducting dc output voltage. The authors reveal a macroscopic phenomenon in which magnetic poles couple and transport millions of magnetic vortices in the superconductor. This explains the physical origin of the HTS flux pump, and will impact the engineering of HTS magnets for applications such as NMR and MRI instruments, wind turbines, fusion power generators, particle accelerators, and magnetically levitated trains.