SELF-FIELD EFFECT AND CURRENT-VOLTAGE CHARACTERISTICS OF AC SUPERCONDUCTORS

Current-voltage characteristics of two superconducting wires for a.c. use in d.c. magnetic fields up to 1 T were studied. They were measured with d.c. transport current as well as with sinusoidal a.c. transport current at frequencies up to 50 Hz. Voltage signals due to the self-f ield effect were obtained and analysed. The measured self-field voltag e is also compared with that obtained from calculations based on the c ritical state model. The self-field losses were estimated by numerical integration of the measured self-field voltage multiplied by instanta neous transport current.