Void ratios and mechanical losses in simulated CIC conductors with non-metallic conduit materials

We have fabricated cable-in-conduit conductors (CICCs) with two kinds of nonmetallic conduit materials. Differences of frictional coefficients on surfaces of the materials vary by factors of two or three, and void ratios of the conductors are from 14% to 42%. We wound these CICCs on same-shaped bobbins, and measured the AC losses of the CICC coils. In spite of the fact that the coil shape, the superconducting wire, and background magnetic fields were the same, the measured losses were not, and depended on conduit materials and void ratios. According to the experimental results, in order to decrease the losses, a conduit material with high frictional coefficient is desirable. It is also shown that the losses decrease with the decrease of the void ratios in the CICCs.