Conductive Micro-Paths for Current Sharing Between REBCO Tapes in High-T c Superconducting Conductors to Improve Stability

Abstract

The REBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">_y</i> (REBCO, RE: Rare Earth) is expected to be applied to fusion magnets, and various REBCO conductors with a high current capacity has been developed for the fusion magnets by stacking the REBCO tapes. A disadvantage of REBCO conductors is that the buffer layer prevents current sharing between the tapes, reducing conductor stability. In this study, we propose conductive micro-paths where the current is shared between the REBCO tapes in order to improve the stability of conductors. We fabricated the conductive micro-paths in REBCO tapes by using a UV pulsed laser and an Ag sputtering method, and evaluated them. Furthermore, we investigated the current sharing between tapes at 77 K with two REBCO tapes with conductive micro-paths. As a result, in REBCO tapes with conductive micro-paths, the current was shared through these paths between the REBCO tapes at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1.1 &lt; I/{I_{\bf{c}}} &lt; 1.15$</tex-math></inline-formula> and was successfully bypassed the damaged area.