The Flux Flow Voltage in a Type II Superconducting Foil in the Presence of a Superposed Perpendicular AC Field

Abstract

The flux flow voltage in a foil of type II superconductor has been shown to suffer a remarkable modification by the application of a small ac magnetic field, even if the frequency is much less than the depinning frequency. In this paper, two types of simple phenomenological theories are derived in the presence of an ac field parallel to the foil by starting from different extreme assumptions. The results of the measurements in this configuration are also presented. The comparison with the present theories shows clearly the applicable ranges of these theories. The present conclusions also suggest the limitations of existing theories for other configurations started from similar assumptions.