Dynamics of a high repetition rate dense plasma focus

摘要

A photographic study of the gas breakdown, development of the current sheath build-up, and the eventual plasma pinching in a high-repetition rate dense plasma focus (DPF) has been made. Image acquisition is via a 12-frame intensified digital camera capable of frame rates of up to 2E8 frames per second (5 ns minimum exposure). The DPF is driven by an impedance matching transformer pulse power driver, and is capable of producing a neutron yield of 3E5 neutrons per pulse up to 10 Hz. The temporal and spatial structure of the current sheath in repetitive mode of operation from 1 to 10 Hz, and at various filling pressure has been investigated. Observations of sheath homogeneity, symmetry, filamentary, and arc formations in the current sheath are critical issues for neutron production.