The Flux Pumping Behavior of High Temperature Superconducting Tapes With a Linearly Moving Electromagnet

Experiments have been done to study the flux pumping behavior of coated conductor tapes under the field of a linearly moving electromagnet with a narrow magnetic field profile. The simple setup made it possible to directly compare the theoretical flux pumping voltage curve with the experimental value. Two pairs of voltage taps were used to measure the voltage curves at both edges of the tape, which are exposed to the sweeping field at different times. The experimental result is compared with the theoretical value from a modified Brandt model where the superconducting tape follows the power-law E - J relationship. The quantitative comparison between the model and the experiments has shown a possible theory for the flux pumping phenomenon, namely that the cross-tape flow of the flux is responsible for the non-zero average DC voltage. The theoretically predicted switching between the flux pump and the dynamic resistance is also observed. The quantitative study of the flux pump is helpful for both better understanding and more efficient design of flux pumps.