Operational characteristics of a superconducting flux pump

A superconducting flux pump of the rotating normal spot type was studied. It is shown that the causes of non-ideal behavior are the eddy currents induced in the normal spot and the switching of the superconducting load current taking place at the leading edge of the spot. The structure of the current, magnetic field and temperature in and around the moving normal zone were derived and the resulting distributions for these field variables were used to calculate effective inductance and resistance of the spot. These parameters, functions of spot velocity, allow the determination of an equivalent circuit for the flux pump as an electric generator.