Transport current AC losses of high-Tc superconducting tapes exposed to AC magnetic field - Study on a new measurement method

A new measurement method is developed to properly measure transport current AC losses of high-Tc superconducting tapes which are subject to external magnetic field generated by adjacent tapes in multiple tapes assembled conductor. It has been pointed out that to correctly measure the AC losses of the tape, the voltage measurement loop should include the magnetic flux over a distance much larger than the tape width. However, this wide voltage loop needs wide space and picks up spurious loss caused by adjacent tapes when multiple tapes are assembled. In our arrangement, the leads from voltage taps on the tape are wound on a cylindrical surface enclosing the tape. This method can save space for voltage leads and avoid spurious loss component caused by the magnetic field of the other tape. In the paper, details of our measurement arrangement are explained and the validity of our method is investigated by theoretical and numerical analyses and an experiment. It is demonstrated that our method is effective.