Auxiliary coil system for Scyllac

The system of auxiliary l = 1 and l = 0 coils for the toroidal Scyllac and Scylla IV-3 θ-pinch experiments at LASL is described in detail including theory of operation, coil design constraints, method of construction and test, and installation configuration. These coils produce magnetic fields of the general form sin(lθ - hz) which, when added to the axial θ-pinch field Bo, provide toroidal equilibrium and a means of feedback stabilization. Because these coils are subjected to both induced and applied voltages, the major engineering effort has been directed toward achieving adequate electrical insulation in the limited space demanded by the low-inductance circuitry. This paper includes the step-by-step construction and test of a typical l-coil. Sophisticated epoxy potting, taping, and spacing techniques have been successfully employed. Dc and pulsed voltage tests to above 100 kV have been conducted prior to installation of the coils on the experiments. Electrical connections are made outside the θ-pinch coil in such a way as to cancel the induced voltages before they can reach the driving capacitor banks.