Self-consistent analysis of the spatial relaxation of a disturbed neon glow discharge

The response of a neon glow discharge plasma on a disturbance caused by a floating Langmuir probe is studied by a fully self-consistent, spatially one-dimensional hybrid method as well as by measurements. The theoretical description is based on the coupled solution of the hydrodynamic equations of electrons, ions, and excited atoms and the Poisson equation. The space-dependent transport and rate coefficients of the electron component are determined by a strict solution of the non-uniform electron kinetic equation. For the measurements, a probe was inserted in radial direction into the discharge several cm in front of the anode. The spatial evolution of the densities of the excited atoms in the 1s(3), 1s(5), and 2p(8) states was determined by spectroscopic methods. Pronounced modulations of basic plasma parameters have been observed around the probe, decaying periodically and damped toward the anode. The measured density profiles of the excited atoms agree well with the numerically determined ones. The analysis of the electron kinetic quantities shows that the response of the plasma to the disturbance is widely determined by the non-local behaviour of the electrons in the distinctly disturbed electrical field