Development of large current capacity Bi-2212 monolithic conductors

Abstract We developed rectangular-shaped Bi-2212 conductors. At 4.2 K and 30 T, the 37- and 349-filament conductors exhibited J C values of 151 and 125 kA/cm 2 , respectively. Moreover, we measured the distribution of I C for a 25 m-class 349-filament conductor. The end-to-end I C value was 66 A at 63 K, self-field, and the variation in I C was about ±10%. We also fabricated a test coil with 50 m-class, 349-filament conductor. The test coil carried 510 A (using a criterion of 10 −13 Ω m) and generated B 0 =0.95 T at 4.2 K without backup field, resulting in a current density in the test coil of 150 A/mm 2 . The coil performance was almost 80% that of a short sample with a magnetic field applied perpendicular to the tape surface.