The influence of de-Maxwellization on a fluorescent lamp simulation

Abstract

A simple three electron temperature model was applied to a one-dimensional, fully self-consistent model of a positive column discharge, as typically found in fluorescent lamps. It was shown that this model yields results that are in good agreement with reality, regarding important parameters such as the electrical conductivity, the electron temperature and the amount of radiation produced, and that it constitutes a significant improvement over a calculation based on a Maxwellian electron energy distribution function.

Experimental investigation of the electron energy distribution function (EEDF) by Thomson scattering and optical emission spectroscopy

“…From the summation over all excitation processes which effectively leads to ionization, an effective total ionization rate can be computed using a CRM, and fitted as a function of an effective Maxwellian temperature. In the electron density range considered here the following formula was proposed [52,53]: k(T e ) = k exc (T e ) = 6.8 × 10 −17 T 0.44 e exp(−12.06/T e ) (5) with T e in eV.…”

“…Equation (5) was originally defined for argon plasmas close to the ESB [49] and so electron densities n e > 2 × 10 19 m −3 . Indeed, it is for 20 mbar that the closest agreement between the ePB and the ALI T e -values was found.…”

“…In the cases where the dependence of the effective ionization rate as a function of a Maxwellian T e is known (as given by equation (5) for instance), this iterative method can be used to correlate the so-called creation temperature of the plasma found by ALI with the real shape of the EEDF. Nevertheless, one needs to know plasma parameters such as the ionization degree and reduced electric field for these conditions and can then use equation (13).…”

“…Depletion/overpopulation of the tail of the EEDF is commonly found, even for simple atomic plasmas [1][2][3]. In the case of gas mixtures, the EEDF can take even more complicated shapes where the distinction between a bulk and a tail temperature becomes itself doubtful [4][5][6][7].…”

Axial mercury segregation in direct current operated low-pressure argon–mercury gas discharges: Part I. Experimental

“…Many new studies have been devoted to the interplay of various mechanisms of positive column of FLs [15][16][17][18][19]. Recently, a grand model was presented which includes the calculation of radiation transport in the 253.7 and 185.0 nm lines, two collisional radiative models to describe the excitation, stepwise ionization of Hg and Ar, self-consistent diffusion and the tail depletion of the electron energy distribution function [20]. All the recent studies are based on the ac excitation and could essentially be restricted to a one-dimensional treatment, since the absence of the dc field implies axial uniformity.…”