Finite Element Method Plasma Simulation of Nitrogen Contaminated Ceramic Metal Halide Lamps

P. Juhász[1], S. Beleznai[1], I. Maros[1]
[1]Budapest University of Technology and Economics, Budapest, Hungary
Published in 2014

The ceramic metal halide lamps belong to the most efficient high intensity light sources of these days. Presently it is the nitrogen contamination that causes the most significant problems during ignition. If this material gets into the lamp's interior in high concentrations, it will make the lamp unable to ignite properly at lower voltages.

A self-consistent fluid model was developed in COMSOL Multiphysics® Plasma Module for studying the discharge phenomena. The results show that the nitrogen dissociation reaction affects the electrons' kinetic energy distribution mainly by electron energy dissipation. The critical nitrogen concentration is around 500 ppm. Higher concentrations create significant change in breakdown process. In this case the breakdown voltage has to be increased in order to achieve ignition.