[en] The invention concerns a superconductor consisting of a number of superconducting filaments which are embedded in normally conducting material like, e.g., copper. In order to suppress coupling effects between th filaments in alternating magnetic fields, the filaments are snaked on circles with different radii around the longitudinal axis of the superconductor, each filament forming a helix concentrical with the conductor axis. If, on the other hand, the alternating magnetic field has a longitudinal component, two coils of different diameter are screening one another, which will cause magnetic instabilities and considerable alternating field losses. In order to prevent this, the filaments according to the invention are alternatingly snaked in opposite sense of rotation, each of the helices formed by the filaments describing a predetermined number of complete turns around the conductor axis in a linear segment corresponding to the alternating length. (FW)