Method for Estimation of Electron Density in a Pulse Plasma Source

The time-dependent spatial electron density distribution in a constricted, pulsed plasma source is measured using a floating hairpin resonance probe, and an extrapolation method is described for determining peak electron density from experimental data. Using these techniques, a detailed characterization of the spatio-temporal evolution of electron density, outside the constricted region above the anode of the pulsed plasma source is presented. Electron density increases sharply during the creation phase, and the rate of increase is found to decrease with the distance from the axis of the constricted channel. By modeling the plasma creation characteristics vs position, the electron density along the axis of the constricted pulsed plasma sources can be determined.