A Critical Current Measurement Method for Strip Hard Superconductors Utilizing Pulsed Current

Abstract

Long wire critical current (Ic) characterization is important for fabrication of superconducting magnets. Many inductive and transport Ic measurement methods have been developed for km scale rare earth cuprate (REBCO) based Coated conductors (CC), which is a very promising high temperature superconducting material for magnet applications. As a direct indication of the current carrying capability, transport measurement is favored by most tape users. However, the traditional transport measurement technique has its limitations for long tape characterization. The speed of transport measurement is usually not high enough for km scale tapes, and direct current (DC) measurement also has a certain risk of tape damage due to the Joule heating at current contacts, especially for some special CCs with higher contact resistance, e.g., stainless-steel encapsulated CCs. For long wire measurements, the risk of tape damage is generally higher than acceptable. A pulse measurement method based on induction principle is proposed and tested in this work, the feasibility of this method is verified by experiments. Where pulsed current is used to reduce Joule heating thus reduce the risk of tape damage. Moreover, the speed of measurement can also be improved by the technique compared with DC measurements.