Compensation of the radial magnetic field component of solenoids wound with anisotropic Bi(2223)Ag tape

The critical current of a solenoid made of Bi(2223)Ag tape with a high anisotropy in the critical current - magnetic field characteristic at 77 K is determined in particular by the radial component of the magnetic field, which is large close to the coil flanges. The original idea of utilizing supplementary (e.g. copper) windings to compensate partially the undesired radial magnetic field component of the high-temperature superconducting (HTS) coil is described. The results of extensive numerical calculations on the model coil indicate that an increase of the critical current of more than 50% can be expected.