Hysteretic ac loss of polygonally arranged superconducting strips carrying ac transport current

TL;DR

This paper theoretically analyzes the hysteretic ac loss in polygonally arranged superconducting strips around a cylindrical former, deriving formulas for total ac loss based on the number of strips and their geometry.

Contribution

It provides an analytical model for ac loss in polygonally arranged superconducting strips, extending understanding of superconducting cable behavior.

Findings

Normalized ac loss depends on the number of strips and their width-to-diameter ratio.

For many strips and small width-to-diameter ratio, the loss resembles that of an infinite array.

Derived formulas match expected behavior in limiting cases.

Abstract

The hysteretic ac loss of a current-carrying conductor in which multiple superconducting strips are polygonally arranged around a cylindrical former is theoretically investigated as a model of superconducting cables. Using the critical state model, we analytically derive the ac loss $Q_n$ of a total of $n$ strips. The normalized loss $Q_n/Q_1$ is determined by the number of strips $n$ and the ratio of the strip width $2w$ to the diameter $2R$ of the cylindrical former. When $n>> 1$ and $w/R<< 1$, the behavior of $Q_n$ is similar to that of an infinite array of coplanar strips.