Hysteresis loss in a coated conductor subject to a combined applied magnetic field and transport current

Hysteresis loss in the superconducting film of a coated conductor is computed for the case where the superconductor carries an ac transport current while being acted upon by a relatively large ac magnetic field applied perpendicular to the film surface. It is shown that the contributions of the ac transport current and ac magnetic field to the loss strongly interact with each other. The importance of the scalar potential due to surface charge on the conductor is pointed out. In general the electric field in a given section of the conductor is the sum of a contribution due to the changing flux density enclosed by the circuit and the electric field of the surface charge. The position of zero electric field in the conductor oscillates back and forth across the conductor width. An alternative expression for the loss is given in terms of a magnetic moment and a dynamic resistance term.