Normal Zone Initiation and Propagation in Y-Ba-Cu-O Coated Conductors With Cu Stabilizer

Abstract

In the ongoing effort to investigate the normal zone behavior of coated conductors, the effects of a localized, pulsed heat disturbance on a YBa/sub 2/Cu/sub 3/O/sub x//Ni-alloy conductor with Cu stabilizer was investigated. The sample was conduction cooled by a GM cryocooler in a vacuum environment, establishing nearly adiabatic conditions. A NiCr wire heater mounted on the sample was used to provide the heat pulse that initiated the normal zone. Consecutive voltage taps along the length of both sides of the sample monitored the propagation of the normal zone. Several thermocouples were glued on both sides of the sample to measure the temperature profile of the conductor. The minimum quench energies and normal zone propagation velocities were measured at ambient temperatures from 58 K to 79 K and transport current ranging from 30% to 90% of I/sub c/. The voltage and temperature profiles are presented and discussed.