Glow-to-arc transitions in gas discharge lamps

Abstract

The Waymouth model, which describes the glow-to-thermionic arc transition in qualitative terms, has been extended. To get a quantitative description of the glow-to-arc transition phenomena in metal halide lamps (with their emitterless electrodes) it is essential to include in the model a current dependent glow voltage. When this is done, the model calculations of the glow time and ignition time are found to agree well with experimental results. The influences of a number of lamp parameters on glow time and ignition time have been investigated in the light of this improved model.

Lifetime prediction of fluorescent lamps used in photovoltaic systems

“…In the glow-to-arc phase, it is difficult to distinguish the process involved: a mixture of sputtering and electron thermal emission. 9 The dynamic transition between the glow and arc phases is usually termed glow-to-arc transition. Nevertheless, to avoid misunderstanding, we have adopted a more precise terminology, which includes three phases (glow, glow-to-arc and arc) and two transitions (glow to glow-to-arc and glow-to-arc to arc), see also Figure 2.…”

“…The determination of the end of the glowto-arc phase (glow-to-arc to arc transition) in different kinds of discharge devices is the subject of many publications (see for example Luijks and Vliet, 9 Boyle and Hawort, 13 Kekez et al 14 and especially Tonegawa and Takayam 15 ). Use of intrusive Langmuir probes with specially designed lamps is the most common technique described in the literature, which is useless for analysing market samples.…”

“…18 This is a very good definition that accounts for the effect of glow current on lamp LT. On the other hand, the role of glow current in electrode damage is a subject of gas discharge lighting engineering. 8,9,19 It is usually accepted that a glow current over 25 mA 20,21 leads to reduction in the lifetime of the lamp. Figure 6 in Hadrath et al 22 shows that when the discharge current is under a certain level (75 mA in that case) the discharge is in the glow mode and barium density in front of the electrode dramatically increases.…”

Modeling of the effect of a dielectric film on the electrode surface upon the discharge glow-to-arc transition

“…The dynamics of discharge transition from the glow to the arc mode was calculated in [22,23] only for metal cathodes. Theoretical investigations of the effect of cathode dielectric inclusions on this process were not performed yet, although the arc discharge lamp electrodes contain oxides of alkaline earth metals as emission material [1][2][3].…”

Breakdown processes in metal halide lamps

“…Although metal halide lamps typically operate in the steady state as multi-atmosphere thermal arcs, during their starting phase the lamps are moderate pressure glow discharges [1][2][3][4][5][6][7][8]. Typical starting conditions for commercial metal halide lamps are a fill of a rare gas such as argon at tens to a few hundred Torr and the vapour pressure of the metal halide dose and/or mercury.…”