Microwave discharges maintained by surface waves: Modelling and experiments

Summary form only given, as follows. Three aspects of surface wave maintained discharges are studied: 1. Numerical modelling of situations when local plasma resonances due to the radial density profile are possible and important. 2. First experimental indications for predictions of the modelling. 3. Peculiarities of the dispersive behaviour due to the combined influence of radial inhomogeneity and collisions. The modelling addresses argon discharges at 0.25-1.5 Torr and radii 3-15 mm at 2.45 GHz. It is based on a nonlocal kinetic approach, including a quasilinear (noncollisional) heating mechanism. Self-consistency is achieved by simultaneous solution of ion fluid and field equations. The radial profiles of electron density and of surface wave electric fields, energies absorbed per averaged electron and resultant axial profiles are calculated. Measurements on electric field profiles in the plasma, electron energy distributions and axial density profiles consistent with theoretical expectations are presented. The dispersive behaviour of the surface waves influenced by radial inhomogeneity and collisions is studied for various conditions.