Modelling of a low-pressure plasma column sustained by a surface wave

Abstract

A complete theoretical description of a low-pressure, cylindrical plasma column sustained by a weakly damped surface wave is derived in which the equations describing the steady-state plasma maintenance conditions are coupled with the surface wave propagation and attenuation characteristics. The present formulation extends a radial theory of the maintenance of the plasma column previously reported to include the axial variation in the radially averaged plasma properties. Simple similarity laws for this type of discharge are proved to exist under quite general conditions. Analytic expressions are derived for the variation of the electron density along the discharge axis and for the length of the plasma column as a function of the operating parameters. The calculation are shown to agree well with available experimental data.