Experimental analysis on temperature characteristics of a rectangular bulk YBCO exposed to alternating magnetic field

The motion of magnetic flux will cause temperature rise inside of a bulk high-temperature superconductor (HTS) when exposed to an alternating magnetic field (AMF). In levitation system, like superconducting motors, bearing and vehicle, however, bulk HTSs are always subjected to ripple fields due to mechanical vibration, as well as harmonic field of armature windings, which will cause energy loss inside of bulk HTSs. Part of the heat caused by the energy loss is transferred to liquid nitrogen (LN 2 ) through the surface of bulk HTSs, and the other part will lead to temperature rise inside bulk HTSs. We experimentally analyzed the temperature characteristics of bulk YBCO under different AMF frequencies in this article. And the effect of AMF on the temperature rise of the bulk HTS under different cooling heights (CHs) and working heights (WHs) was also studied. The results showed that the higher the CH, the greater the temperature rises inside the bulk HTS. Besides, the temperature of the whole bulk HTS increases with the decrease in the WH and the increase in AMF frequency. The results and analyses of this article are useful for the application of bulk HTSs in the high-speed rotating and transportation systems.