Modelling the Hg-rare gas low-pressure positive column

Summary form only given. The authors describe the modelling of an Hg-rare-gas low-pressure discharge operating in DC and AC modes by using a collisional-radiative model and the similarity principle. In the case of DC operation, a uniform steady state positive column established in a circular cross section tube is considered. The knowledge of the electron energy distribution function (EEDF) is very important. For example, the relative difference between transition rates calculated by using different EEDF approximations can each 90% in the case of the 7/sup 3/S/sub 1/ /spl rarr/ 6/sup 1/S/sub o/ transition. An AC power supply is also considered. Experimental data on the relative flux of the Hg (254 nm) resonance line has been used to validate the calculations.