How Computational Physics is evolving part1

Abstract: A hybrid kinetic-fluid model is used to study ionization waves (striations) in DC discharges in noble gases at low plasma densities. Coupled solutions of a kinetic equation for electrons, a drift-diffusion equation of ions, and a Poisson equation for the electric field are obtained to clarify the nature of plasma stratification in the positive column and near-electrode effects. A simplified two-level excitation-ionization model is used for the conditions when the nonlinear effects due to stepwise ionization, gas heating, and Coulomb interactions among electrons are negligible. It is confirmed that the nonlocal effects are responsible for forming moving striations in DC discharges at low plasma densities. The calculated properties of self-excited nonlinear waves of s, p, and r types in Neon and s type in Argon agree with available experimental data.