Field and current distributions and ac losses in superconducting strips

TL;DR

This paper analytically and numerically investigates magnetic-field and current distributions, as well as ac losses, in superconducting strips with various cross-sectional shapes and parameters, enhancing understanding of their electromagnetic behavior.

Contribution

It introduces new methods to analyze ac transport-current losses in superconducting strips with different cross-sectional geometries and flux-dependent critical current densities.

Findings

Loss dependence on cross-sectional shape and aspect ratio

Analytic expressions for magnetic and current distributions

Impact of flux-dependent critical current density Jc(B) on ac losses

Abstract

In this paper I discuss analytic and numerical calculations of the magnetic-field and sheet-current distributions in superconducting strips of width 2a and arbitrary thickness 2b at the center when the cross section is an ellipse, a rectangle, and a shape intermediate between these limits. Using critical-state theory, I use several methods to determine the functional dependence of the ac transport-current losses upon F = I/Ic, where I is the peak alternating current and Ic is the critical current, and I discuss how this dependence can be affected by the cross-sectional shape, aspect ratio, and a flux-density-dependent critical current density Jc(B).