COUPLING LOSSES IN CABLES FOR FUSION APPLICATION - INFLUENCE OF THE STRAND

The coupling time constant of conductors for fusion magnets must be ke pt at a sufficiently low value to minimize the temperature increase re lated to the rapid field variations experienced by the pulsed coils du ring a run, Some parameters such as the twist pitches and the void fra ction are well known to influence the coupling time constant, Another parameter which can play a role is the strand itself through its elect rical characteristics. Two identical conductors can have very differen t time constants and it is important to understand the strand paramete rs which govern this effect, To demonstrate that, several 36 strands s ubcables have been made with strands coming from different companies a nd associated to different manufacture processes (bronze Nb3Sn, intern al tin Nb3Sn, NbTi), As far as possible the other parameters of these cables have been kept identical, Contact resistance and time constants have been measured and compared for the different samples.