Investigation of possible electric potential arising from a constant current through a superconductor coil

Abstract

Edwards et al (1976 Phys. Rev. D 14 922) reported that they had observed an I2-dependent potential resulting from constant current in closed superconducting NbTi, Nb and Pb coils at rest. We have reiterated these experiments and improved them with several variations to understand the nature of Edwards' potentials in more detail. However, at the same time, the current-induced electric field and the potential were not discovered if the Teflon-ground system, which was the base of the superconductor coil assembly, was removed. Our experiments and estimations show that Edwards' potential can arise due to the piezoelectric effects in the Teflon insulator of the superconducting coil assembly. This result is especially important, because papers that cite the results of Edwards et al and are based on their conclusions continue to be published to date.