The Thermal State of High-Temperature Supercondacting Current Leads during Disarrangement of Superconductivity

Abstract

The thermal state of the current leads containing high-temperature superconductors is analyzed. The transition to the normal state of superconductor in a contact connection with an uncooled resistive section of the current lead is considered. The expressions were obtained that determine the temperature and heat flux in the current lead under overloading at different values of transient electrical resistance in the heat-insulated or cooled by a cryogenic liquid brazed joint. Based on the proposed calculation technique, the behavior of the maximum temperature in the resistive section and of the maximum temperature in the contact depending on the current density are revealed when the ratio is changing between the transient resistance and the longitudinal resistance of the contact. It is revealed that if the transient resistance is determined mainly by the transverse resistance of a solder, with minimal nonconductive intracontact formations, then, when the current density increases, the critical parameter that determines the efficiency of the current lead is the maximum temperature of resistive section. The considered method for studying the thermal behavior of the current lead with a high-temperature superconducting wire under overloading conditions can be used for comparative evaluation of the current leads of superconducting devices to determining the values of limiting temperatures in the current lead given different design and physical parameters.