Ac operation of low-pressure He–Xe lamp discharges

Bussiahn, R.; Gorchakov, Sergey; Lange, Hartmut; Loffhagen, Detlef; Uhrlandt, Dirk

doi:10.1088/0022-3727/40/13/s07

Cited by 8 publications

(6 citation statements)

References 23 publications

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“…Nonthermal plasmas are widely used in many technical applications including plasma display panels, energy saving lamps, devices for microbial decontamination and ozonizers [1][2][3][4]. They are characterized by low gas temperatures g in the range from 300 to 1000 K and comparatively high mean electron energies T e  between 1 and 10 eV, where 1 eV corresponds to temperature of 11605 K. Computer simulations of electric gas discharges producing nonthermal plasmas are used since many years to get a deeper understanding of fundamental processes and to improve technical devices [5][6][7][8][9][10]. In order to describe all phenomena taking place in the discharge mechanism, in principle, a mathematical model comprising the kinetic Boltzmann equation [11]       has to be solved in combination with Maxwell's equations for the electric field E and the magnetic field .…”

Section: Introductionmentioning

confidence: 99%

Derivation of Moment Equations for the Theoretical Description of Electrons in Nonthermal Plasmas

Becker¹,

Loffhagen²

2013

APM

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The derivation of moment equations for the theoretical description of electrons is of interest for modelling of gas discharge plasmas and semiconductor devices. Usually, certain artificial closure assumptions are applied in order to derive a closed system of moment equations from the electron Boltzmann equation. Here, a novel four-moment model for the description of electrons in nonthermal plasmas is derived by an expansion of the electron velocity distribution function in Legendre polynomials. The proposed system of partial differential equations is consistently closed by definition of transport coefficients that are determined by solving the electron Boltzmann equation and are then used in the fluid calculations as function of the mean electron energy. It is shown that the four-moment model can be simplified to a new drift-diffusion approximation for electrons without loss of accuracy, if the characteristic frequency of the electric field alteration in the discharge is small in comparison with the momentum dissipation frequency of the electrons. Results obtained by the proposed fluid models are compared to those of a conventional drift-diffusion approximation as well as to kinetic results using the example of low pressure argon plasmas. It is shown that the results provided by the new approaches are in good agreement with kinetic results and strongly improve the accuracy of fluid descriptions of gas discharges.

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Section: Introductionmentioning

confidence: 99%

Derivation of Moment Equations for the Theoretical Description of Electrons in Nonthermal Plasmas

Becker¹,

Loffhagen²

2013

APM

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“…Because of the complexity and still large computational expenditure, such modelling has been widely restricted either to time-dependent, spatially homogeneous plasmas or to stationary, spatially one-dimensional conditions so far [59][60][61]. Examples of the analysis of nonstationary and inhomogeneous plasmas, respectively, by means of selfconsistent hybrid methods performed at INP Greifswald concern the temporal behaviour of pulsed high-pressure glow discharges [62,63], decaying plasmas [64] and pulsed and ac-driven low-pressure glow discharges [65,66] as well as axial inhomogeneities in the anode region of dc glow discharges [67], the response of glow discharge plasmas to a local disturbance [68], radial structures in the column plasma of dc glows [60,61,69] and in cylindrical hollow-cathode discharges [70].…”

Section: Some Aspects Of Electron Boltzmann Equation Based Hybrid Met...mentioning

confidence: 99%

“…The temporal evolution of the axial electric field has been determined from the solution of equations describing the external electric discharge circuit related to the experiments reported in [66]. The equivalent electrical circuit obtained in accordance with the experimental setup and included in the model is shown in figure 6, where U 0 (t), U d (t) and I d (t) are the generator voltage, discharge voltage and discharge current, respectively.…”

Section: Spatiotemporal Evolution Of a Sine-wave-driven He-xe Lamp Di...mentioning

confidence: 99%

Advances in Boltzmann equation based modelling of discharge plasmas

Loffhagen

Sigeneger

2009

Plasma Sources Sci. Technol.

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The paper reports on advances in numerical modelling of gas discharge plasmas with the focus on hybrid methods which combine a fluid description of the plasma species with the solution of the Boltzmann equation of the electrons. The time-and space-dependent treatment of the kinetic equation of the electrons is based on the two-term approximation of the velocity distribution function and the quasi-stationary description of the anisotropic part of the velocity distribution. Basic aspects of the hybrid approach are given and the integration of the kinetic equation of the electrons into the self-consistent description of non-isothermal plasmas is represented. New hybrid methods have been applied to analyse the spatiotemporal evolution of one-dimensional glow discharge plasmas in inert gases. In particular, the relaxation behaviour of a neon glow discharge disturbed by a short laser pulse and the periodic evolution of the radially inhomogeneous column plasma of a He-Xe lamp discharge are discussed.

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“…In the high intensity discharges that are used in light sources [1][2][3][4], as well as in free-burning arcs [5][6][7][8], radiation escape is one of the primary channels of energy losses in the discharge, which happens because the radiation intensity abruptly grows with plasma temperature.…”

Section: Introductionmentioning

confidence: 99%

The role of visible and resonance radiation in the energy balance of LTE plasma in argon

Golubovskiǐ¹,

Maiorov²,

Gorchakov³

et al. 2014

Plasma Sources Sci. Technol.

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Energy losses due to radiation in an LTE arc plasma in argon are investigated in the temperature range from 5000 to 15 000 K. Calculations of the radiation transport require us to know the absorption spectra; for that purpose, free-free, bound-free and bound-bound transitions are taken into account. The energy losses due to resonance transitions with large absorption coefficients are analyzed. The transport of visible radiation with small absorption coefficients is calculated by accurate integration over a whole spectrum. The resonance radiation transport in LTE plasma is described by the Biberman-Holstein equation, which is usually used in non-equilibrium plasma. As the temperature grows, radiation processes become the main channel of energy losses. It is shown that, despite the resonance radiation being trapped, the energy losses due to resonance radiation escape can achieve 10% of the total radiation losses.

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Ac operation of low-pressure He–Xe lamp discharges

Cited by 8 publications

References 23 publications

Derivation of Moment Equations for the Theoretical Description of Electrons in Nonthermal Plasmas

Derivation of Moment Equations for the Theoretical Description of Electrons in Nonthermal Plasmas

Advances in Boltzmann equation based modelling of discharge plasmas

The role of visible and resonance radiation in the energy balance of LTE plasma in argon

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