Optical diagnostics in high current pseudospark discharges

Summary form only given. The pseudospark is a low-pressure gas discharge, in which breakdown is at the left branch of the paschen curve. It has meanwhile found world-wide interest as a device for fundamental research and many applications such as high power switches and pulsed electron beam devices. The basic design consists of two electrodes with central apertures which are separated by an insulator. The discharge starts in the hollow cathode and can be triggered by injection of electrons into this region. By the hollow geometry discharge initiation is controlled. Later on electrode phenomena like the "superdense glow" and successive explosive electron emission processes describe the transition to an arc-like high current phase. The paper presents measurements of plasma parameters as a function of gas type and electrode material. The experimental methods used are Laser Induced Fluorescence (LIF), laser absorption spectroscopy, tomographic two-wave interferometry and fast shutter and streak photography.