Experimental and theoretical study of AC losses in variable asymmetrical magnetic environments

TL;DR

This study investigates AC losses in high-temperature superconductor tapes within asymmetric magnetic environments through experiments, analytical calculations, and simulations, revealing the effects of shielding arrangements on losses.

Contribution

It combines experimental measurements with analytical and finite-element modeling to analyze AC losses in asymmetric magnetic shielding configurations, highlighting the impact of eddy currents and hysteresis.

Findings

Good agreement between simulations and measurements at central positions

Discrepancies increase near the shields due to eddy currents and hysteresis

Analytical solutions accurately predict current and field profiles in certain geometries

Abstract

Measurements of AC losses in a HTS-tape placed in between of two bulk magnetic shields of high permeability were performed by applying calorimetric techniques for various asymmetrical shielding arrangements. The experiment was supported by analytical calculations and finite-element simulations of the field and current distributions, based on the Bean model of the critical state. The simulated current and field profiles perfectly reproduce the analytic solutions known for certain shielding geometries. The evaluation of the consequent AC losses exhibits good agreement with measurements for the central position of the tape between the magnets but increasing discrepancy when the tape is approaching the shields. This can be explained by the increasing contribution of the eddy currents and magnetic hysteresis losses in the conducting shields.