Asymptotic layer-type model of high pressure direct current glow dischargein electronegative gases

Here a self-consistent one-dimensional continuum model is presented for a n arrow gap plane-parallel dc glow discharge. The governing equations consist of continuity and momentum equations for positive and negative ions and el ectrons coupled with Poisson's equation. A singular perturbation method is developed for the analysis of high pressure dc glow discharge. The kinetic processes of the ionization, electron attachment, and ion-ion recombination are included in the model. Explicit results are obtained for the asymptoti c limits: delta=(r(D)/L)(2)--> 0, omega=(r(S)/L)(2)--> 0, where r(D) is the Debye radius, r(S) is recombination length, and L is the gap length. The d ischarge gap divides naturally into four layers with multiple space scales: anode fall region, positive column, transitional region, cathode fall regi on and diffusion layer adjacent to the cathode surface, its formation is di scussed. The effects of the gas pressure, gap spacing and dc voltage on the electrical properties of the layers and its dimension are investigated. (C ) 2000 American Institute of Physics. [S0021-8979(00)00813-6].