Coupling losses in finite length of superconducting cables and in long cables partially in magnetic field

The coupling losses between strands in cables of LCT conductor type in changing transverse magnetic fields were calculated for two situations envisaged in a. c. loss measurements: a) magnetic field applied on finite length of an infinite cable (infinite as well as finite short circuited cables were considered); b) finite length of cable in spatially independent magnetic field. It is found that in the first case the losses per length are enhanced considerably above loss generation e. g. in a magnet. If one cabling length l
o
is exposed to the field, the losses are enhanced by a factor about 2. This factor decreases only very slowly towards 1, if the field region increases. The results are explained by considering short circuited cables of different length with one cabling length in applied magnetic field. On the other side, the coupling losses of a finite piece of cable with length
l \geq l_{o}
are close to those in an infinite cable in magnetlc fleld, being identical with them for l = nl
o
(n-integer). The results for both cases mentioned above are discussed in the view of different loss measurement arrengements for cables.