AC Losses in Coil Wound From Round Wire Coated by a Superconducting Layer

Numerical simulations have been performed in order to predict the behavior of a round wire covered by thin superconducting layer when exposed to AC magnetic field or transporting AC current, as well as for a solenoid coil made from such wire. It was found that the AC loss of a single coated round wire is in good agreement with the predictions based on the existing analytical results for a hollow superconducting cylinder. AC loss in the coil shows two regimes. At low currents it is lower than in the case of the coil made from a full round wire with the same critical current and outer radius. In the range of currents comparable to the critical current the loss superseded the values expected for the reference coil from full wire. These results indicate, that the use of coated round wires instead of full ones does not offer a significant advantage from the point of view of AC loss in a coil winding.