Coupling losses in cables in spatially changing ac fields

The coupling losses between strands of multifilamentary superconductors can be important in alternating and pulsing magnetic fields. Up to now, mainly spatially homogeneous applied fields were considered.In this paper, the coupling losses in cables of the EURATOM-LCT-conductor type are calculated for transverse ac fields periodically changing along the cable. Sinusoidal, triangular and trapezoidal field distributions are taken into account as special cases. The losses are enhanced by some orders of magnitude for the sinusoidal field, when the ‘wave length’ of the field I_m comes close to the cabling length I_o. This enhancement is expressive also for triangular and trapezoidal fields, if the wave length of the Fourier components is close to I_o.Some consequences of this effect are pointed out, important for designing larger magnets (eg for the fusion, for generators, etc.)