Speaker
Description
"Making HTS conductors constrained by the poor superconducting properties of grain boundaries suitable for high field magnet and especially for accelerator use has been a 30 year odyssey. At the NHMFL we have placed particular emphasis on Bi-2212 because of its round-wire, multifilament architecture. Over the last several years we have shown that it can be processed into high Jc forms that can be used for small high field magnets at >30 T, that its flexible architecture can be realized industrially, that its overall wire Jc can exceed that of any other HTS conductor (except for REBCO in H||ab orientation) and that it is functionally isotropic, possessed of a low hysteretic loss (very similar to ITER Nb3Sn conductors) with a high conductivity normal matrix without any need for a diffusion barrier. At 20 T, 4.2 K its supercurrent Jc has now reached 6000 A/mm2 (whole wire Jc ~1200 A/mm2 with present 20% fill factors) in industrially produced wires of lengths > 1 km. In short, both for solenoids tested at the NHMFL, and in racetrack coils made by Shen at LBL, the promise of Bi-2212 for high field applications made major strides in 2017. I will summarize recent progress in the Bi-2212 effort at the NHMFL and our interactions with B-OST, US powder producers and LBL relevant to this effort.
We would like to thank our collaborators at Bruker-OST, nGimat, MetaMateria and LBL and funding support from the U.S. Department of Energy, Office of High Energy Physics under Award Number DE-SC0010421. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1157490 and the State of Florida. "
