Simulations of geometrically pinched argon plasmas using an extended one-dimensional model

The subject of this paper is the modelling of a wall-stabilized cylinder symmetric cascaded are which is to be used as a high-density plasma source. To enhance the ion flux emerging from cascaded are argon plasmas the confining wall can be changed into a nozzle geometry. Such pinched geometries increase the degree of ionization and convert the subsonic flow to supersonic. To study arcs with a varying cross section we introduce a one-dimensional non-local thermal equilibrium hydrodynamical model. In this model the various contributions in the momentum and energy balance are integrated over the plasma cross section. The radial profiles of the axial velocity and the electron and heavy particle temperatures are prescribed. The influence of the radial profiles on the flow and on the degree of ionization is studied for various are geometries. The model is validated against experimental data and previous results.