The normal zone in YBa2Cu3O6+x-coated conductors
Abstract:We consider the distribution of an electric field in YBa2Cu3O7-x (YBCO)-coated conductors for a situation in which the DC transport current is forced into the copper stabilizer due to a weak link—a section of the superconducting film with a critical current less than the transport current. The electric field in the metal substrate is also discussed. The results are compared with recent experiments on normal zone propagation in coated conductors in which the substrate and stabilizer are insulated from each other. The potential difference between the substrate and stabilizer, and the electric field in the substrate outside the normal zone, can be accounted for by a large screening length in the substrate, comparable to the length of the sample. During a quench, the electric field inside the interface between YBCO and the stabilizer, as well as in the buffer layer, can be several orders of magnitude greater than the longitudinal macroscopic electric field inside the normal zone. We speculate on the possibility of using microscopic electric discharges caused by this large (~kV cm-1) electric field as a means to detect a quench.
Document Type: Research Article
Publication date: December 1, 2007