AC loss properties of Bi-2212 Rutherford-type cables

We investigated the AC loss properties of a Bi-2212 Rutherford-type cable with large current capacity for future SMES. The cable is composed of 20 strands with a diameter of 0.8 nim and reinforced by Ni based alloy, which is located in the center of the cable. The width and thickness of cable are 9.05 and 2.25 nun respectively. The strand has 61 x 7 filaments and the average diameter of the 61 filament bundle is about 0.2 nun. The critical current of the cable is about 2.9 kA at 4.2 K and 0 T. We measured the AC losses in the strand and the cable at 4.2 K by pick-up coil method. The AC loss in the strand was scarcely dependent on frequency since it was not twisted. On the other hand, the AC losses in the cable had remarkable frequency dependence. It may be due to the coupling current between strands. We quantitatively discuss the AC loss of the cable in comparison with theoretical evaluation. (C) 2001 Elsevier Science B.V. All rights reserved.