MODELING OF MICROWAVE-EXCITED GAS-DISCHARGES

This paper is dealing with the power density versus electric field cha racteristic of microwave-excited discharges on the example of typical CO2 laser gas discharges. The fundamentals of the method are a simple electric equivalent circuit for the excitation structure and the assum ption of a fixed reduced electric field intensity within the plasma. T his operating field is enforced by the plasma under stationary conditi ons and can be calculated using an electron balance under consideratio n of the non-Maxwellian electron energy distribution function. The cal culations turn out that c.w. excitation with microwaves is involved wi th considerable plasma power densities. In the case of the CO2 laser t his requires special discharge channel designs for effective gas cooli ng. Besides a discussion of the plasma characteristic, measurements ta ken from a microwave applicator are presented and compared to the calc ulations.