Losses in superconducting wires with inhomogeneous and anisotropic matrix conductivity over cross section

Methods of calculating energy losses for multifilamentary wires with anisotropic and inhomogeneous conductivity of a matrix over the cross section are developed, in particular, for wires with a cluster assembly. Analysis of diffusion of the magnetic flux and dissipative characteristics for the multifilamentary wire in the transverse AC magnetic field shows that: (1) in the case of the matrix anisotropic conductivity the processes of current coupling are antiparallel, making a contribution to losses, which is proportional to one of the matrix components, σ₁; (2) the presence of the matrix conductivity inhomogeneity causes peculiarities in the saturation process, namely, that the longitudinal-to-the-filaments electric field has local maxima at the outer and the inner radii; (3) this circumstance explains the process of parallel saturation of groups of filaments and the wire as a whole, taking place in the wire with cluster assembly; and (4) the rise of the ratio of hysteresis losses to the filament diameter with decrease of the latter for diameter ~1 μm can be accounted for by the cluster saturation and increase of filament inhomogeneity in their thinning without recourse to the proximity effect