Next-generation highly flexible round REBCO STAR wires with over 580 A mm−2 at 4.2 K, 20 T for future compact magnets

Autor: Goran Majkic, Soumen Kar, Venkat Selvamanickam, Dmytro Abraimov, Jithin Sai Sandra, Jan Jaroszynski, Mehdi Kochat, Wenbo Luo
Rok vydání: 2019
Předmět:
Zdroj: Superconductor Science and Technology. 32:10LT01
ISSN: 1361-6668
0953-2048
Popis: We report the latest developments of next-generation flexible round RE–Ba–Cu–O (REBCO, RE = rare earth) wire, driven by the needs of compact accelerator magnets requiring round isotropic wire with an engineering current density (J e ) of 600 A mm−2 at 4.2 K, 20 T at a bend radius of 15 mm. We have developed a Symmetric Tape Round (STAR) REBCO wire using multiple layers of REBCO tapes specifically developed for this architecture, featuring a mechanically symmetric geometry with a 10–18 μm thick substrate wherein the superconductor film is positioned near the tape's neutral plane for superior bend strain tolerance. Furthermore, each layer of REBCO tape is individually optimized for maximum bend strain tolerance. These ultra-thin substrate REBCO symmetric tapes enabled us to fabricate next-generation isotropic round wires of just 1.3 mm diameter and a critical current equivalent to commercial 12 mm wide REBCO tapes. The in-field performance of STAR wires of several configurations has been tested at National High Magnetic Field Laboratory to identify the most suitable architecture to meet the needs of high-field compact accelerators. At a bend radius of 15 mm, a six-layer STAR wire exhibits critical current of 778 A at 4.2 K in 20 T background field, which equals J e of 586.4 A mm−2 at a Lorentz force (F L ) of 15.5 kN m−1 which is the highest reported J e value for REBCO wire in round geometry at this magnetic field. Similarly, a 12-layer STAR wire shows an I c of 1156 A at 31.2 T, 4.2 K which corresponds to a Lorentz force of 36 kN m−1. Multiple tests of STAR wires at high magnetic field confirm a
Databáze: OpenAIRE
Externí odkaz: