AC losses of an infinitely long superconductor cylinder surrounded by a metallic sheath

We study the AC losses in a structure composed of an infinitely long superconducting cylinder surrounded by a metallic sheath. The system is subjected to an axial alternating magnetic flux. The AC losses are evaluated locally in each material and compared to the situation where no metallic sheath is used. The superconductor region is described by the Bean-Kim model, while the metal is assumed ohmic and non-magnetic. The variation of the magnetic flux in the superconductor directly affects the eddy currents in the metal sheath. This back-reaction is modelled numerically through a Fourier decomposition of the electrical and magnetic field at the interface between the superconductor and the metal. The resulting losses are evaluated as a function of the frequency and the amplitude of the source field.