Fundamental Evaluation of Joint Resistance in Mechanical Butt Joint of a Stacked GdBCO Conductor

Abstract

In this study, joint resistance in mechanical butt joint of a single GdBCO tape was evaluated by experiments and current distribution analyses to apply a remountable HTS magnet for a future fusion reactor. The results showed that thickness of the metal layers of GdBCO tape, cutting angle of the conductor and existence of soldered interface affect the joint resistance. According to discussion based on the results, an optimized joint structure could achieve joint resistance of 0.4 µΩ for single GdBCO tape, which correspondsto 5 nΩ for 100 kA class HTS conductor. The resistance has to be reduced almost a half value of the present result to be accepted from the view point of electric power for cooling.