High Pressure Microhollow Cathode Discharges

Old Dominion University Research Foundation, Norfolk VA

Investigators

Abstract

This is an investigation of fundamental plasma physics and chemistry in microhollow cathode discharges (MHCDs) with the objectives of determining (1) characteristic lengths of plasma boundary layers in microhollow cathode discharges to provide information on coupling mechanisms between opposite cathode falls; (2) plasma parameters that determine the rate of generation of excimers, such as electron density, electron energy, gas temperature, discharge current and discharge voltage; and (3) the optical gain of high-pressure MCHDs with the goal of explain their possible use as a micro excimer laser medium. The experimental studies are supported by computer modeling. The relations of global discharge parameters to fundamental plasma properties and the scaling of excimer laser gain in xenon-chloride MHCDs are investigated computationally. Microhollow cathode discharge (MHCDs) are nonthermal high-pressure gas discharges between a hollowcathode and a planar or hollow anode with electrode dimensions in the range of 100 micrometers. The large concentration of high-energy electrons and the high neutral-gas density favor three-body processes such as excimer formation. This along with the simplicicty of design and operation, make these systems attractive candidates for light sources, sources of charged particles, and micro plasma reactors.