Numerical Simulation Of Atmospheric Pressure Glow Discharge Controlled By Dielectric Barrier Between Two Concentric Electrodes

A review is presented of the article associated with the development of plasma and its application. The generation of plasma under the lower atmospheric pressure is limited to vacuum condition. For overcoming the disadvantages of vacuum operation, all kinds of methods obtaining large-volume, high-pressure (especially atmospheric pressure), non-equilibrium plasmas have developed. It provides the arc discharge, the corona discharge, the dielectric barrier discharge, and the plasma jet, as well as their applications in industry in this paper. The recent efforts to obtain the homogenous atmospheric pressure glow discharge are also discussed. By contrasting the characteristics among theirs, it can be seen that the plasma jet can generate stable uniform plasma. We have adopted the same discharge configuration known as between wire-cylindrical electrodes to discuss the discharge characteristics of plasma generated by the dielectric barrier discharge at atmospheric pressure.At atmosphere pressure, the glow discharge in helium in an axially symmetrical dielectric barrier system is investigated basing on the one-dimensional self-insistent fluid model. In calculation, the discretization of continuity equation is performed in accordance with semi-implicit Scharfetter-Gummel scheme and the electric field is solved by the current conservation instead of the Poisson's equation, so it saves plenty of time for calculation. By solving the one-dimensional continuity equations for electrons, ions and excited atoms, coupled to the current conservation equation, the spatial-temporal distributions of the electric field and the electrons, ions and excited atoms densities, as well as the time evolutions of the discharge current, the gas voltage and the surface charge density on the dielectric barrier are calculated. The simulation results show that the peak values of the discharge current and the electric field are asymmetry in the former and latter half cycle. When the current reaches the positive and negative maximums, the distributions of the electric field, electrons and ions density have the same properties as the typical low pressure glow discharge, obviously existing the cathode fall, the negative glow column and the positive column. The influences of the barrier position between two electrodes and the discharge gap width to discharge current characteristics is also discussed. When covering the dielectric on the outer electrode only, the gas punctures earliest during the first half-period and latest during the second half-period, andthe discharge current magnitude is the biggest, as well as the difference of the pulse width is the most obvious. By reducing the gap width, the multiple current pulse discharge happens.