Prediction of AC losses in MgB ₂ superconducting wires as a function of transport currents and temperatures

We propose two methods to predict the AC transport current losses of MgB ₂ superconducting wires with respect to various operating currents (I _tr) and temperatures (T). Firstly, the transport current loss was estimated by a numerical method (finite element analysis). In order to consider the highly nonlinear behavior of the superconducting properties according to magnetic flux density (B) at each temperature, the measured J _c-B-T characteristics were used in the calculation. The numerical results were compared with these of conventional Norris theory and showed quite good coincidence. A second method to predict the transport current loss at various temperatures, which used a loss at a specific temperature and the critical current data, is suggested. We deduce a formula for the prediction of the loss by a simple analogy through normalization, which performs excellently. The comparison of the transport current loss values calculated using the two methods is addressed.