The effect of magnetic field orientation on the critical current of HTS conductor and coils

The critical current of short samples of HTS multifilamentary conductor and ring-shaped coils has been measured at helium temperatures with varying magnetic field orientation with respect to the conductor. The samples and coil conductor consist of a multifilamentary composite of BSCCO-2223 filaments in a silver matrix. Short conductor samples were tested in a variable temperature system with up to 8 T background field using a sample rotational system. Ring-shaped coils made from the sample type of conductor were exposed to a large background field at liquid helium temperatures and critical current was measured with the ring located at various axial positions within the bore. As the ring moves closer to the end of the magnet, the measured critical current decreases, even though the magnitude of the field to which the ring is exposed decreases. This decrease in J/sub c/ is due to the strong anisotropy of the superconductor and is consistent with short sample measurements. >