A 3-MA compact-toroid-plasma-flow-switched plasma focus demonstration experiment on Shiva Star

We describe a novel dense plasma focus experiment using the Shiva Star capacitor bank, which uses a compact toroid (CT) magnetized plasma flow switch (PFS) to initiate the focus implosion. The CT armature stably and reproducibly translates up to 3 MA from the vacuum feed region through coaxial electrodes to the gas puff central load. The inertia of the 1 mg CT and the work that must be done in compressing the internal magnetic fields during the translation provide a delay in current delivery to the pinch of 5 – 10 µs, which matches the bank quarter cycle time relatively well. Effectiveness of the current delivery was monitored primarily by inductive probes in the PFS region, fast photography of the focus, and x-ray and neutron measurements of the pinch. K shell X-ray yields using neon gas were as high as 1 kJ, and 10⁸ neutrons were produced in a deuterium gas focus.