Behaviour of multifilamentary Nb-Ti conductors with very fine filaments under A.C. magnetic fields

Long lengths of multifilamentary Nb Ti composites, which comprise several thousands .5 to 1 micron-diameter filaments, have been manufactured. These composites, with a Cu-Cu Ni mixed-matrix and some of them with pure Cu Ni between the filaments, carry hight current densities up to 1.95 105 A/cm2 at 5 Teslas. Their structure provide a good magnetic stability and leads to strongly reduced 50 Hertz losses. These results allow to consider alternators with superconducting rotor and armature windings and, in a general way, they open very new prospects for industrial applications of superconductivity in fast pulsed magnets and in A.C. current devices