AC loss of multifilamentary superconducting AC wire caused by longitudinaland azimuthal AC magnetic field components

AC loss characteristics of multifilamentary NbTi AC wires under AC external magnetic field were experimentally and theoretically investigated. We meas ured AC transport current losses of AC wires with various twist pitches und er the AC external magnetic field which included longitudinal and transvers e components. It was shown by the measurement that the AC transport current losses decreased with decreasing the twist pitches when the external and s elf longitudinal fields were in the same direction. The measured dependence of the AC losses on the twist pitches and the applied longitudinal field c omponent were well explained by our previously derived model. We also theor etically estimated the AC losses caused by the longitudinal and azimuthal f ield components. It was found that the AC losses can be substantially reduc ed by properly selecting the twist pitch and the external longitudinal fiel d component.