Superconducting electrical conductors

Claim 1

An electrical conductor in a changing magnetic field comprising a plurality of filaments of a material which is superconductive at temperatures of about 4.2* K. and above contained within and separated from one another by a matrix of at least one material which is not superconductive at about 4.2* K., each filament having a maximum thickness of about 0.005 cm. and being twisted or transposed about the other filaments with a length L along the conductor between each return of that filament to a given angular position relative to the conductor given by the relationship: where k is a space factor equal to the ratio between the linear dimensions of superconductor and those of superconductor plus matrix materials in a direction parallel to the magnetic field in which the conductor operates, J is the critical current density in amps/cm.2 of the superconductor material (in zero or very low magnetic fields), d is the average thickness in cms of each filament perpendicular to the magnetic field, p is the electrical resistivity in ohm-cms of the non-superconductor material separating the filaments from each other and having the highest electrical resistance, B is the rate of change of field in gauss/second, and a is a number which is greater than 3 and is sufficiently large for the variation in flux rate of change B along the length L divided by the mean flux rate of change B along the length L to be less than the thickness d divided by the thickness of the conductor perpendicular to the field.