AC loss calculation in high-temperature superconductor wires and windings with analytical and numerical models: influence of J_c(B) dependence

Too high loss levels can severely limit the efficiency and the safe operation of several high-temperature superconductor (HTS) AC applications. A reliable estimation of AC losses, which includes the observed field-dependence of the superconductor's critical current density on the magnetic field, is therefore paramount. In this contribution, we use numerical simulations to evaluate the AC losses of HTS coated conductors in a variety of working scenarios: individual wires carrying AC transport current and/or subjected to AC magnetic fields, and wire assemblies like stacks and arrays carrying AC transport current. Numerical results are compared to the corresponding analytical models and to experimental results. This work presents some general guidelines regarding the extent to which the dependence of the critical current density J_c on the magnetic flux density B modifies the AC loss characteristics with respect to a constant-J_c model based on the superconductor's self-field critical current.