Normal zone propagation experiments on HTS composite conductors

As high temperature superconductor magnet applications become a reality due to increases in conductor performance, it is important to understand the behavior of normal zones in conductors and magnets in order to design safe magnet systems. Here we study the effects of localized heat pulses in Ag-alloy sheathed Bi2Sr2Ca2Cu3Ox powder-in-tube conductors and Ni-alloy substrated YBa2Cu3Ox coated conductor tapes cooled by N-2 gas. A heater was used to initiate a normal zone. The experimental setup to measure the energy required such that the normal zone propagates and the normal zone propagation velocity in the longitudinal direction is described. Results for both conductor architectures are presented. (C) 2003 Elsevier Science Ltd. All rights reserved.