A super-conductive wire includes a plurality of super-conductive filaments embedded within a metal matrix. A heat shield layer is circumferentially disposed about the matrix so as to prevent the ingress of diffusion of heat into the matrix from the exterior of the wire, and a plurality of longitudinally extending grooves are defined within the surface portion of the wire to such a radial depth as to penetrate the heat shield layer and therefore permit the matrix of the wire to be in direct thermal contact with a coolant disposed about the exterior of the wire so as to permit heat within the matrix to be discharged therefrom to the exteriorly disposed coolant.
