Influence of Mechanical Vibration and Losses Under AC Operating in Bi-2223 Tapes With Ionic Liquid Impregnation

Mechanical loss in superconducting coils is one of the important parameters for the stability of high temperature superconducting coils (HTS coil). We prepared three kinds of impregnations (no impregnation, ionic liquid grease), measured the AC loss of the Bi-2223 tape under DC magnetic field in liquid nitrogen and quantitatively estimated the relation between the impregnation and losses. As a result, the loss can be reduced about 40% by using ionic liquid compared with no impregnation. We consider that the tape impregnated with ionic liquid is effective to reduce the AC loss. The results become fundamental data to reduce the AC loss of conduction-cooled HTS coils.