Spectroscopic investigations of a Plasma Opening Switch using a novel gaseous plasma source

Abstract

A novel gaseous plasma gun (PG) was developed for spectroscopic investigations of the plasma behavior in a cylindrical Plasma Opening Switch (POS) in the nanosecond time regime. The PG injects the plasma radially outward from inside the high-voltage inner conductor to fill the region between the two conductors. The PG uniformity, reproducibility, electron density and temperature, and plasma flow velocity were determined using floating probes, biased charge collectors, fast photography, and spectroscopic methods. The POS operation was examined for various plasma parameters for a positive polarity of the inner conductor. Eight B loops and two Rogowski coils were used to measure the upstream and downstream currents. Ion current flowing during the switch operation from the plasma through the cathode was measured by two arrays of four collimated Faraday cups placed on two opposite sides of the plasma switch. Spectroscopic observations of high spatial and spectral resolutions of various particle velocities in the plasma were made. Excited level populations, velocity distributions, and directed velocities for various ions are discussed. Measurements of a secondary plasma originating from both electrodes are presented.