AC Loss in MgB2 Superconducting Wires at Various Operating Temperatures

We investigate the AC loss behavior in MgB2 wires using numerical calculations based on the finite element analysis (FEM). The governing equation for the system was formulated using a magnetic vector potential and an electric scalar potential, taking into account the non-linear, field dependence of the critical current density (Jc). The model incorporated the results of measurements of the Jc-B of for a real MgB2 wire. For this, we directly measured the Jc-B characteristics according to the external fields as well as various temperatures. A transport current loss analysis was performed on the MgB2 wire for a wide range of transport current values and different temperatures. The magnetization loss was also calculated as a function of the external magnetic field and temperature. For both type of losses, the numerical results were found to be in good agreement with those obtained by theoretical calculations, thus verifying the validity of the model.