Current distribution and ac loss for a superconducting rectangular strip with in phase alternating current and applied field

TL;DR

This paper investigates ac transport and ac loss in a superconducting rectangular strip under in-phase alternating magnetic fields, using numerical models and experimental validation to understand the critical state behavior.

Contribution

It provides a detailed numerical analysis of ac loss and current distribution in a superconducting strip with finite thickness, comparing with analytical limits and experimental data.

Findings

Numerical results match experimental data without fitting parameters.

Critical state model reveals complex metastable phenomena.

Defined a loss factor for detailed ac behavior analysis.

Abstract

The case of ac transport at in-phase alternating applied magnetic fields for a superconducting rectangular strip with finite thickness has been investigated. The applied magnetic field is considered perpendicular to the current flow. We present numerical calculations assuming the critical state model of the current distribution and ac loss for various values of aspect ratio, transport current and applied field amplitude. A rich phenomenology is obtained due to the metastable nature of the critical state. We perform a detailed comparison with the analytical limits and we discuss their applicability for the actual geometry of superconducting conductors. We also define a loss factor which allow a more detailed analysis of the ac behavior than the ac loss. Finally, we compare the calculations with experiments, showing a significant qualitative and quantitative agreement without any fitting parameter.