Plasma Composition and Diffusion in the Near-Wall Region of a Capillary Discharge

The internal structure of the discharge plasma in a capillary with evaporating walls made of the compounds CH₂ and СF₂ is considered. The experimental data obtained for the central region make it possible to identify two near-wall layers (rings) with their own plasma composition characteristics and transfer process kinetics. The mechanisms of radial separation of the mixture components have been established, starting with thermal diffusion in a neutral gas near the wall and enhanced by ambipolar diffusion of carbon ions with electrons from the ionized layer of the near-wall region. As a result, movement of the lightweight component towards the center is accelerated many times, while the heavy component slows down so that the central region is filled with light gas (H or C ions) and the near-wall region is predominantly filled with heavy gas (C atoms and ions or F atoms). Directions for further research are identified.