Experiment And Simulation Research On The Coaxial Gridded Hollow Cathode Glow Discharge Plasma

Large volume, high density and uniform spatial distribution plasma has important implications in industry application and scientific research. Due to the low density of the neutral particles and long free path of the electrons, a large volume and uniform plasma could be generated more easily under low-pressure. In this paper, a device called coaxial gridded hollow cathode(CGHC) discharge that can generate large volume, high density and uniform plasma based on the glow discharge is manufactured. The experiment and simulation research on the CGHC glow discharge properties are conducted.First, a deeply theory analyzes on the basic conditions of glow discharge, the Townsend discharge model and the drift and diffusion of the charged particles in the plasma are presented. The affecting factors on the properties of the plasma are found. Then a series of gas discharge experiment are conducted under different conditions(different gas, different gas pressure, different applied voltage etc.). The electron temperature and electron density are measured by the Langmuir probe. We can find the influence rules of the discharge condition by analyzing the experimental data. Finally, a numerical simulation on the CGHC glow discharge is performed by using the fluid model, because understanding the physical processes of CGHC operation is important for its improvement and optimization. A two-dimensional fluid model was built using COMSOL Multiphysics to study the main plasma parameters distribution in the discharge chamber in argon. The model was based on the continuity equations for electrons and ions, momentum equation, energy equation(only for electrons), coupled with Poisson’s equation. The spatial and radial distributions of plasma potential, electron density and electron temperature were developed and discussed. The plasma sheath thickness around the electrodes was obtained. The comparisons of simulation results with available experimental data were presented to show the validity of the model. Research shows that large volume, uniform and controllable density plasma can be generated under different conditions, the experimental data and simulation results are basically consistent.