Detailed structure of dc glow discharges - Effects of pressure, applied voltage, and gamma-coefficient

By use of the Particle-in-Cell/Monte-Carlo method, structures of de glow discharges in argon are examined for p(g) (gas pressure) = 26-74 mTorr, V-0 (applied voltage) = 500-1000 V, and gamma (secondary electron emission coefficient) = 0.1-0.3. A self-consistent simulation is performed by using a set of the most accurate collision cross sections. Recourse to approximations and assumptions that are not necessarily valid is avoided as far as possible. The effects of p(g), V-0 and gamma on the discharge are systematically examined. In the bulk plasma there do exist high-energy beam electrons. Although the number of these electrons is very small, their contribution to the mean electron energy is appreciable. A time-independent spatial oscillation of plasma density is found for some discharge: conditions. For the same conditions similar oscillation of mean ion velocity and excitation rate are observed. Copyright (C) 1996 Elsevier Science Ltd.