This paper describes the theoretical evaluation of AC losses in the oxide superconductors with smooth transport properties. First, conventional expressions of AC losses are reviewed for the n-value model, in which the local electric field is proportional to the power of local current density. The superconductor under consideration is a slab with infinitely wide faces, to which an external AC magnetic field is applied along the surfaces. It is also assumed that the critical current density and n-value are independent of the magnitude of local magnetic field. As a result of theoretical consideration by combining Maxwell's equations and the n-value model for the voltage-current characteristics, it is pointed out that the loss factor can be determined by only two parameters. Next, a new type of expressions is proposed for the AC loss evaluation, and it is concluded that a discrepancy is less than 17% between analytical and numerical results.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics