Fast Time-Relaxation Algorithm to Solve Plasma Fluid Equations

This paper presents a fast time-relaxation quasi-implicit algorithm to solve plasma fluid-type equations for the transport of electron particles and mean energy, the transport of heavy species (ions and neutrals), the balance of the gas thermal energy, and the description of the fields (space-charge electrostatic and electromagnetic) affecting the plasma. The algorithm separately solves and converges the different model equations, within quasi-independent calculation modules, taking advantage of their characteristic relaxation times. In particular, the full solutions to the electron and ion transport equations are sequentially obtained, contrary to the procedure usually adopted in plasma fluid-type models. The algorithm is applied to the 1-D modeling of atmospheric-pressure microplasmas in argon, produced within the end gap of a microstrip-like transmission line by a continuous microwave excitation (at 2.45-GHz frequency). The runtimes are of 25-60 min on a 2.66-GHz CPU for the convergence criteria imposing global errors smaller than 10^-4- 10^-7.