Strong reduction of ac losses in a superconductor strip located between superconducting ground plates

TL;DR

This paper analytically investigates how superconducting ground plates significantly reduce ac losses in a superconductor strip, providing exact formulas for power losses and resistance based on the strip's environment and current parameters.

Contribution

It introduces an analytical method using the method of images to precisely calculate ac losses in a superconductor strip with superconducting ground plates, highlighting the reduction in losses with closer proximity.

Findings

Resistance decreases as the distance to ground plates decreases.

Exact formulas for power losses are derived.

Superconducting ground plates effectively reduce ac losses.

Abstract

The problem of calculating the ac losses in a superconductor strip with a transport current placed inside superconducting environments is studied analytically in the frame of the critical state model. Exact results obtained by the method of images for the commonly employed flat ground plates are used to derive power losses and, consequently, the nonlinear resistance depending on the ac frequency, current amplitude and the distance to the ground plates. The resistance is strongly reduced when the distance between the strip and the shields becomes small.