Theoretical parametric investigation of plasma sustained by traveling electromagnetic wave in coaxial configuration

• Published in: Vacuum 2018-09, Vol.155, p.280-291
• Main Authors: Bogdanov, T., Benova, E.
• Format: Article
• Language: English
• Subjects: Coaxial plasma; Microwave discharges; Surface-wave-sustained discharges
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2018.06.010

The electromagnetic wave traveling along a dielectric–gas interface can produce and sustain gas discharge in various geometrical configurations. We propose a parametric study of surface-wave-sustained plasma in coaxial configuration at low pressure based on stationary 1.5D (1D for plasma density and 2D for the wave electromagnetic field components) model. At this configuration the plasma is produced outside a dielectric tube in a low pressure chamber when at the tube axis a metal antenna is arranged. The model gives the phase diagrams and the axial distribution of the plasma density, wave power, wave number, and wave field components, as well as the radial distribution of the wave field components. The dependence of wave and plasma characteristics on the geometry parameters (the plasma radius, the dielectric tube thickness, and the metal antenna radius) and on the dielectric tube permittivity is investigated and shown in this paper. The discharge conditions at which it is possible to sustain plasma by an azimuthally symmetric wave are obtained. Comparison with the cylindrical plasma in corresponding conditions and with experimental data is also presented. •The theoretical modeling of surface-wave-sustained plasma in coaxial configuration at low pressure is proposed.•The plasma is considered as a part of the waveguide structure including also the others media.•The parametric study based on this model shows an important role of the geometry parameters and the dielectric permittivity of the waveguide on the plasma properties.•The plasma density is lower than that in cylindrical configuration and can be lower than the resonant one in a big part of the plasma column.