Abstract: A superconducting solenoid with compensation for axial gradients of orders 1 through 7 is formed of a superconducting wire having a rectangular cross-section. The wire is wound as a solenoid having a longitudinal axis and multiple helical layers, adjacent ones of which are pitched in opposite directions. The solenoid includes a main winding portion, as well as auxiliary and supplemental winding portions at each end of the main winding portion. The auxiliary and supplemental winding portions, respectively on the interior and exterior cylindrical faces of the main windng portion, compensate for the second and fourth order gradients. A further winding portion in the center of the main winding portion, on the interior cylindrical face thereof, compensates for sixth order axial gradients. The odd order gradients are compensated because each of the winding portions have approximately an equal number of turns on opposite sides of a centrally located transverse axis of the main winding portion.

Abstract: A persistence switch comprises a diode and superconductive wire in thermal contact with the diode. The heat evolved by current through the forward biased diode raises the temperature of the superconductor above the transition temperature. The diode characteristic of the switch permits a plurality of such switches to be arranged in a network for selection by a relatively few signal conductors.