On the density of metastable and resonance atoms in a stratified positive column in neon

The densities of metastable and resonance states 3(3)P(2) (S5) and 3(1)P(1) (S2) are measured by a method of laser absorption in S and P striations in neon at low (1.4 Torr) and intermediate (12.8 Torr) pressures. The theoretical description of excited atoms in striations requires the solution of the nonlocal kinetic equation in a spatially periodic field to obtain the excitation rates, as well as the analysis of both the resonance radiation transport and diffusion equations for excited atoms. The solution of the radiation transport equation is obtained for the case of both the radial and axial (in particular, periodic) inhomogeneities The densities of excited atoms are calculated in different striation phases taking into account the transport processes, direct intermixing by atomic and electron impact, and intermixing by excitation and radiation of the system 2p(5)3p. Comparison of the theoretical and experimental results is performed for weakly nonlinear striations near a lower bound of existence by pressure and striations at low and intermediate pressures.