Current leads with high Tc superconducting bus bars

The feasibility of combined current leads with a superconducting extension using high-T_c superconductors is demonstrated. The performance of systems with heatsink at room temperature or at LN₂ temperature are compared. In both cases the leads and the busbars are cooled by counterflowing helium gas and the superconducting part can be, depending on T and I, in the superconducting state, in the normal state, or in the current-sharing regime. The improvement obtained by such a system is important notwithstanding the limited current capacity of today high-T_c superconductors, at least for the LN₂ -cooled system