Rare-gas-halide discharge stability

Osborne, M. R.

doi:10.1007/bf00687158

Cited by 18 publications

(5 citation statements)

References 24 publications

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“…A filamentary discharge structure, in particular at large laser energy depositions, resembles that of discharge pumped excimer lasers [18,19]. However, the filamentary formation mechanism known as 'halogen depletion instability' [20][21][22][23] does not seem to be valid in our case because an electronegative gas is the main component of the mixtures treated and 'burn away' during the discharge. In discharge pumped excimer lasers, a filamentary structure is assumed to arise from the electric field non-uniformity in the discharge gap due to either the electrode surface inhomogeneities [24,25] or a nonuniform gas pre-ionization [26].…”

Section: Generalmentioning

confidence: 81%

Electron detachment instability and self-organization in strongly electronegative polyatomic gases

Belevtsev

Firsov

Kazantsev

et al. 2009

J. Phys. D: Appl. Phys.

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This paper reports on an investigation of the ionization instability and related phenomena in a self-sustained volume discharge (SSVD) in SF6-based mixtures pre-irradiated by a pulsed CO2 laser. The illumination geometry with a diaphragm slit arranged normal to the central electric field line of the discharge gap is considered. The delay times between the laser and voltage applications were varied from a few to several tens of microseconds. The formation and some special features of quasi-periodic filamentary structures in laser-heated SF6-based mixtures at different delays are studied. It is hypothesized that the self-organization observed is caused by the ionization instability developed in the SSVD plasma due to an imbalance between the rates of electron detachment by electron impact and electron–ion recombination. The mathematics of this instability in a zero-dimensional approximation and the characteristic time of its development are given. An imbalance-caused mechanism of conducting channel propagation in SF6-based mixtures at room temperature under the conditions approaching those of the HF laser performance is suggested. It starts from an appreciable decrease in electron–ion recombination rate in an enhanced electric field in the vicinity of the channel tip. The effect of a two-step ionization is assessed.

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Section: Generalmentioning

confidence: 81%

Electron detachment instability and self-organization in strongly electronegative polyatomic gases

Belevtsev

Firsov

Kazantsev

et al. 2009

J. Phys. D: Appl. Phys.

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“…We can explain our results when the processes leading to the breakdown of the laser gas mixture are taken into account, and the fact that a F 2 -containing discharge inherently gets unstable. Discharge instabilities are developed in a few ns from minor preionisation inhomogeneities, electrode irregularities, cathode hotspots, and/or local gas density fluctuations [10,[16][17][18]. Unstable discharges generate low or no laser output because pumping power is lost in the discharge streamers and because plasma filamentation disturbs the optical properties of the medium.…”

Section: Resultsmentioning

confidence: 99%

“…cm −3 ) should be enhanced to the discharge electron density (∼ 10 14 el. cm −3 ) [10,11] before inhomogeneities can arise. Net electron multiplication takes place when the interelectrode voltage V AC is higher than the steadystate voltage V SS .…”

Section: Excitation Circuitsmentioning

confidence: 99%

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On the performance of an ArF and a KrF laser as a function of the preionisation timing and the excitation mode

Feenstra¹,

Hoekstra²,

Peters³

et al. 2000

Appl Phys B

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An X-ray preionised ArF and KrF excimer laser has been studied with three different spiker-sustainer excitation circuits. We observed large differences in the laser performance, when the preionisation delay timing was varied on a nanosecond timescale. The behaviour of both lasers was found to be equivalent. The observations can be understood by considering the effect of the discharge excitation technique on the preionisation process. An excitation mode with a prepulse well above the steady-state voltage V SS with a subsequent reversed overshoot voltage for initiating the discharge, in combination with a well-timed preionisation pulse is found to give the best results. Optimum output energies of 50 mJ with ArF and 175 mJ with KrF were obtained from an active volume of 60 × 1.5 × 1.2 cm in the so-called swing mode, with the preionisation applied 60 ns before the discharge breakdown.

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“…However, the development of a dishomogeneity in the active medium of discharge lasers seems to play a key role in the deterioration process [7]. Theoretical models are now available to study the role of chemistry [8][9][10][11][12][13][14] and the effects of the non-uniform energy deposition and flowfield in discharge pumped XeCl excimer laser [15]. Unfortunately, their developments do not take into account the role of gas dynamics following the power deposition in the medium, which could be one of the causes that leads the discharge instability process.…”

Section: Introductionmentioning

confidence: 99%

Effects of neutral particle dynamics in the active medium of discharge pumped XeCl lasers

Lamrous

Mezeghrane

Mitiche

et al. 2003

J. Phys. D: Appl. Phys.

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A powerful fluid model to study the role of gas dynamics in a glow discharge considered as an excitation medium for XeCl lasers is presented. This model was employed using a numerical code including four strongly coupled parts: electric circuit equations, electron Boltzmann equation, kinetic equations and conservation equations. The theoretical formalism presented here is based on the two-dimensional Euler equations describing the perfect compressible fluid. The numerical calculations have been carried out considering the single shot regime and neglecting the gas flow. The monotonic upstream centred scheme for conservation laws corrections has been used in order to estimate the exchange flow surrounding the control volume walls. We show that the crossing discharge induces a thermal energy density enhancement located principally in the cavity centre.

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Rare-gas-halide discharge stability

Cited by 18 publications

References 24 publications

Electron detachment instability and self-organization in strongly electronegative polyatomic gases

Electron detachment instability and self-organization in strongly electronegative polyatomic gases

On the performance of an ArF and a KrF laser as a function of the preionisation timing and the excitation mode

Effects of neutral particle dynamics in the active medium of discharge pumped XeCl lasers

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