Design of shielded pulsed power toroid

The AC-shielded pulsed coil concept introduced at the University of Wisconsin Applied Superconductivity Center uses superconductive coils for fast discharges. The superconducting part of the coil is shielded from AC fields by a cryogenic shield that carries all the AC currents and produces zero field in the superconducting coil. The AC-shielded coil may be either a solenoid or toroid. For the solenoid, the turns of the cryoresistive part are arranged around the superconducting winding to produce zero field on the superconductive turns. For toroids, the cryoresistive part is inside the superconducting coils and restricts the AC fields to the toroidal core without superconductor interaction. A major advantage for toroids is the zero external field; it can pulse undetected. The disadvantage is that toroids require twice as many conductors as the solenoids and about 20% more structure. The author selects toroids based on the zero external field advantage