Coupling losses in various outer normal layers surrounding the filament bundle of a superconducting composite

In multifilamentary composites submitted to a changing external field, coupling currents between the filaments give rise to the so-called coupling losses. These losses can be reduced by using a three-component matrix in the filament bundle itself. However, in the outer normal-conducting layer surrounding the bundle of filaments, significant extra losses from azimuthal coupling currents exist if the thickness of the layer is not small. One can expect a reduction of these losses by introducing a cupronickel shell. The losses are calculated in the three particular cases involving one, two, and three concentric layers of different resistivity.