INTERSTRAND EDDY-CURRENT LOSSES IN RUTHERFORD CABLE

A continuum model is used to calculate the interstrand eddy current loss in the Superconducting Supercollider (SSC) magnets, and expressions are derived for the conductivities. An advantage of the model is that three contributions to the loss can be investigated separately: (1) the contribution of crossover conductance between strand layers; (2) the contribution of conductance within a layer; and (3) the contribution of edge conductance. Furthermore, it is not necessary to assume that each interstrand resistance is the same. The result obtained for (1) is just a generalization of Morgan's expression. Resistance measurements by Kovachev at al. indicate that in some parts of the magnet (2) and (3) are negligible compared with (1), while in other places the former are the same order of magnitude as (1). The case for a different type of cable (cable-in-conduit) is also discussed briefly.