Superconducting-to-Normally Conducting Transitions in Strip Transmission Line Structures

Abstract

A theoretical and experimental investigation of superconducting-to-normally conducting transitions in strip transmission line structures is presented. The theoretical analysis is based on a macroscopic model, which is the transmission line analog of the Pippard model. It is assumed that during the transition a superconducting-normally conducting (S-N) interface propagates along the transmission line structure. This situation is treated theoretically as a moving boundary value problem. The S-N interface propagation velocity is determined explicitly in terms of the current that induces the transition, the operating temperature, and the superconductive penetration depth. Experimental results indicate that the model is useful for predicting the transition time of a strip transmission line structure.