Spectroscopic investigations of a plasma opening switch using a novel gaseous plasma source

Summary form only given. The behavior of a current-carrying plasma in a cylindrical plasma opening switch (POS) configuration has been investigated. A novel gaseous plasma gun, installed inside the inner high voltage (300 kV, 90 ns) conductor, injects the plasma radially outward into the region between the electrodes. The source-plasma density, flow, and uniformity prior to the current conduction are studied using various electric probes, microwaves, and spectroscopic diagnostic techniques. The plasma properties are determined time-dependently as a function of the axial and radial positions. This is achieved by the use of local plasma seeding obtained by employing laser evaporation techniques together with appropriate optical arrangements. The velocity distributions of various species and charge-state ions are obtained from line Doppler broadenings and shifts before and during the high-current application. The electron density distribution and electric fields in the plasma are studied using spectral Stark profiles of hydrogen lines. Excited-level populations for various particles are analyzed using time-dependent collisional radiative calculations, yielding the local total particle densities and the time-dependent ionizations in the plasma.