A modern perspective on flow instability and shockwave phenomena in reacting gas multiphase system excited by direct current

A critical analysis of physical insights into ionization waves, plasma states, and attendant phenomena in a gas discharge plasma excited by direct current discussed in the literature is performed. A comparison between synergy bifurcation and kinetic bunching models shows that the former is undoubtedly close-to-perfect and “useful,” and it “is an accurate representation of the real world from the perspective of the intended uses of the model” in the range of gas pressures from 1 to 100 Torr, whereas the latter is obviously imperfect. The latter model is no perspective. The basic factors and ideas definitely established at the early stage of studying striations and current jumps in the discharge are briefly reviewed. The synergy aspect invoking the diffusion-reaction equations, catastrophe theory, and ionization equilibrium principle is demonstrated to permit us to better understand the physics of ionization waves and the underlying physical processes and also to establish a natural and useful link between the parameters of a physical system. Conditions and specific features of their formation and propagation directions are determined. Based on modern concepts of the physical nature of striations and current jumps, it is demonstrated that these ionization waves propagating in a gas discharge are typical ionization-diffusion shock waves.