Numerical Simulation On DC Glow Discharge With Varied Gas Pressure

Glow discharge, especially DC glow discharge is an active topic in gas discharge. It is one of the plasma producing key means which widely applied in film deposition, surface modification and has been studied in many ways.Gas pressure plays a very important role in gas discharge。In the past times, most research works of the experiments and simulations were under a fixed pressure. The article describes the numerical simulation on DC glow discharge with varied gas pressure. In order to understand the mechanism of glow discharge with varied gas pressure very well, a numerical simulation on the DC glow discharge with varied linearly gas pressure is performed by means of a one-dimensional slab fluid model. The pressure ranges from 1.0 torr to 100 torr. The results are gotten that include the space distribution of electron density, ion density, electron temperature and electric field and their evolution. We also discuss these results and analyze the effects of the speed of gas pressure variations in gas discharge.In chapter 1, briefly introduce the research history and application of gas discharge,basic particles of gas discharge,particles collided theory and moving means, at last explain basic types of gas discharge and the laws of DC glow discharge on low pressure in detail.In chapter 2, briefly introduce the analyzed models of plasma discharge in low temperature: fluid model,kinetic model and Monte Carlo model, especially explain the basic theory of fluid model concretely.In chapter 3, a numerical simulation on the DC glow discharge with varied linearly gas pressure is performed by means of a one-dimensional slab fluid model, and has gotten some numerical results by using finite volume approach. We find that: the densities of electrons and ions are increasing with decrease of pressure varied velocity around ranges of a certain pressure varied time, electron temperature,electric potential and field only changes at sheath, but increment is smaller and smaller. When the velocity of varied pressure is fixed, with increase of pressure, the density of particles is increasing, and increment is bigger and bigger; the sizes of discharge areas are changing simultaneity. In positive column, the density of particles,electron temperature and field intend to keep balance with increase of pressure varied time.