Analysis of energy dissipation in HTS tape due to perpendicularly applied collinear ac and dc magnetic field

We present an experimental and theoretical investigation of magnetization energy dissipation in commercially available high-temperature superconducting (HTS) tape due to collinearly superimposed ac and dc bias magnetic fields applied perpendicularly to the tape's plane. Numerical calculations based on the A-formulation finite-element method (FEM) models were used to simulate the changes in shielding current distributions leading to the ac loss occurrence. Simulations performed with the presented modeling approach clearly show the minimum in simulated loss characteristics and give reasonable agreement with experiments. It is shown that the occurrence of the ac loss minimum in HTS tapes for the studied configuration of magnetic fields is mainly caused by the interaction of trapped flux with shielding currents induced in the superconducting material.