Modelling radiation transfer in low pressure discharge lamps

The purpose of this paper is to present and to discuss some aspects of the radiative transfer modelling in low pressure discharge plasmas. Direct computation of the radiative flux is time consuming especially when a good description line profile is needed. Several attempts have been made in order to minimise the computation time. In this paper we show a new approach of this problem which leads to a drastic reduction of the calculation time. This calculation based on successive transformations of the radiative transfer equation is used in order to determine the resonance radiative flux outside the lamp for a mercury-argon low pressure discharge taking into account Hg-Hg and Hg-Ar collisions. This method also leads to the emission photometry. The Lambertian emission hypothesis for meridians plans limits significantly time calculation. We describe a particular method (OPT model) based on the localisation of the more effective contribution areas relative to each one of the integrated functions. This method permits us to validate some of our results.