Current profiles and AC losses of a superconducting strip with elliptic cross-section in perpendicular magnetic field

TL;DR

This paper investigates the current distribution and AC losses in a superconducting strip with an elliptic cross-section under a perpendicular magnetic field, using a combination of numerical and analytical methods based on the critical-state model.

Contribution

It introduces a novel analytical approximation assuming elliptical current profiles and derives expressions linking magnetization to applied fields, validated against experimental data.

Findings

Numerical current profiles ensure complete shielding without predefined assumptions.

Analytical elliptical current profile approximation matches experimental AC susceptibility data.

Derived magnetization expressions cover the entire range of applied magnetic fields.

Abstract

The case of a hard type II superconductor in the form of strip with elliptic cross-section when placed in transverse magnetic field is studied. We approach the problem in two steps, both based on the critical-state model. First we calculate numerically the penetrated current profiles that ensure complete shielding in the interior, without assuming an a priori form for the profiles. In the second step we introduce an analytical approximation that asumes that the current profiles are ellipses. Expressions linking the sample magnetization to the applied field are derived covering the whole range of applied fields. The theoretical predictions are tested by the comparison with experimental data for the imaginary part of AC susceptibility.