新しい高温超電導コイル構成法による遮蔽電流磁界低減の実験的検証

抄録

We propose a new structure for layer-wound coil manufactured using a high-temperature superconducting (HTS) wire in the form of a tape to reduce the central magnetic field produced by screening currents induced on the broad surfaces of HTS tapes. Reducing this screening current-induced field is based on the abnormal transverse-field effect observed generally in the mixed state of Type-II superconductors. The structure proposed enables the inner bore of special coil required nuclear magnetic resonance systems to be used effectively. However, it cannot eliminate the screening current-induced fields completely because the innermost and outermost parts of the HTS winding are always exposed to magnetic fields weaker than the full penetration fields. We carry out a series of experiments to confirm the effectiveness of reducing the screening current-induced fields in a HTS coil fabricated with a commercially available coated conductor.