New method of initiating multi-megampere, multi-megajoule plasma focus discharges using magnetized plasma flow switches

Summary form only given. We describe a novel dense plasma focus experiment at the Shiva Star facility (operated at 1 MJ-2 MJ capacitor bank energy), which uses a compact toroid (CT) magnetized plasma flow switch to initiate the focus implosion downstream from a shielded vacuum insulator. The CT armature stably and reproducibly translates up to 3 MA from the vacuum feed region through coaxial electrodes to a puffed-gas 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-/spl mu/s ps, which matches the bank quarter cycle time relatively well. Effectiveness of the current delivery was monitored by primarily by inductive probes in the PFS region, fast photography of the focus, and X-ray and neutron measurements of the pinch. No evidence of current loss was observed.