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

摘要

Summary form only given. We describe a novel dense plasma focusexperiment at the Shiva Star facility (operated at 1 MJ-2 MJ capacitorbank energy), which uses a compact toroid (CT) magnetized plasma flowswitch to initiate the focus implosion downstream from a shielded vacuuminsulator. The CT armature stably and reproducibly translates up to 3 MAfrom the vacuum feed region through coaxial electrodes to a puffed-gascentral load. The inertia of the 1 mg CT and the work that must be donein compressing the internal magnetic fields during the translationprovide a delay in current delivery to the pinch of 5-μs ps, whichmatches the bank quarter cycle time relatively well. Effectiveness ofthe current delivery was monitored by primarily by inductive probes inthe PFS region, fast photography of the focus, and X-ray and neutronmeasurements of the pinch. No evidence of current loss wasobserved