Numerical Investigation on Induced Current Distribution and AC Losses in a Prototype Cable for the European DEMO TF Coils

A new geometrical model has been implemented in the THELMA code, aiming at permitting the study of multistage, forced-flow cable-in-conduit conductors with rectangular cross-section, like that proposed for the toroidal field (TF) magnets of the future fusion reactor DEMO. This model gives verisimilar strand trajectories which should enable the adoption of a more detailed interstrand electrical contact model. This paper shows the results of the first application of these new code features to a set of contact resistance and ac loss experiments carried out by Twente University on a DEMO TF prototype conductor. The results of this analysis present some unforeseen aspects that need further work to be fully understood, to improve and validate the model.