One-dimensional analysis of electronegative discharge plasmas with four charged species

We develop a parabolic model and a flat-top model for high-density plasma d ischarges of oxygen gases. These models are based on the equilibrium of a f our-species (O-2(+), O+, O-, and e) electronegative gas discharge. Such a d ischarge can consist of an electronegative core and electropositive edge re gions, but the electropositive regions become small for the highly electron egative plasma considered here. The approximation of a parabolic or a flat- top negative-ion profile results in algebraic equations which can be solved numerically over a range of parameters. These models consist of the energy and the particle balance equations. For a specified discharge length, abso rbed power, and pressure, as well as specified electron temperature-depende nt reaction-rate coefficients and surface recombination constants, we solve the energy and the particle balance equations to determine the densities o f all species and the electron temperature. The results for typical cases a re compared with the experimental data.