2D Modeling of Dynamic Contraction in Chemically Reactive Non-equilibrium Plasma Flow*

Dynamic contraction in weakly ionized plasma has attracted attention for decades. It occurs when a homogeneous volumetric plasma transits into a filamentary channel. This process is critical for plasma applications including gas lasers, plasma-assisted ignition, and fuel reforming. In this work, a time-dependent two-dimensional plasma model is formulated by considering detailed plasma kinetics, chemical kinetics, transport models, and electrical circuit. The diffusion-drift approximation is applied for charged species. The near-electrode sheaths are not considered and the plasma is assumed quasi-neutral. By perturbing the steady-state plasma column, a filament is propagating from one electrode to another. The contraction is shown to be not only dominated by the well-known thermal-ionization mechanism but also by chemical heat release/absorption and chemical kinetics. The work integrates the modeling of the weakly ionized plasma and chemical kinetics, which is of practical interest for plasma-assisted chemical processing.