Proposal for an Alternative Criterion for Critical Current in HTS Coils

Abstract

The critical current represents a fundamental performance of superconducting coils and their applications. It defines the limit of the ability to transfer current as a superconductor. Despite the disparate magnetic field environments experienced by HTS wires when current flows through HTS wire or coil, the identical criteria are used to define the critical current. The criteria employed in research papers over the past decade were reviewed and ambiguities were identified. To further clarify the criteria, the critical current of an HTS coil was estimated using FEM simulation, and an alternative method and criterion for determining the critical current was proposed. The HTS coil was wound, and the critical current was measured and compared using the conventional of 100 μV/m and proposed criteria. The results were discussed in detail.