Modeling nonlinear coupling between plasma, electrodes and walls for high-pressure Hg arc discharge lamps

This paper presents a model able to give a global description of the functi oning of high-pressure Hg are discharge lamps, with operation in the diffus e cathode mode. For computational simplicity reasons the lamp is fed on d.c . voltage. The nonlinear interactions between different zones (positive col umn, electrodes and walls of the discharge tube) is considered through Neum ann-Dirichlet mixed boundary conditions at interfaces. We take into account the nonlinearity of physical characteristics of the electrode material and of the silica envelope. Waymouth's measurements are used for the ratio bet ween electron and ion currents. The temperature profile index as function o f the z-coordinate is determined in the vicinity of the cathode.