Nonlinear properties of high amplitude ionization waves

Nonlinear equations describing the state of a weakly ionized plasma in an unstable positive column are derived from a set of hydrodynamic equations, the Poisson equation, and the ionization frequency equation for the direct ionization process. In order to find the solution of the initial value problem, an iterative method is applied. Numerically solved examples show that unstable ionization waves develop into high amplitude relaxation waves—striations. From the calculated distributions of the governing physical quantities particle-like properties of high amplitude striations are established. A nonlinear interaction between striations leading to their collision is noted. The explosive nature of ionization instability is found to be most pronounced at low ionization losses of electron energy. A quantitative, as well as qualitative agreement between calculated and experimental data is obtained.