Diffusion-path approximation in nonlocal electron kinetics

Golubovskiǐ, Yu. B.; Rabadanov, K. M.; Nekuchaev, V. O.

doi:10.1134/s1990793117010183

Cited by 7 publications

(6 citation statements)

References 12 publications

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“…The formation of distribution function is caused by relatively slow acceleration of electrons in the longitudinal field and the fast electron transits in radial potential. Under these conditions, the coefficients of the kinetic equation can be averaged over the radial transits, due to the feasibility of the diffusion approximation [26]. When the radial potential varies weakly along the radial axies and rises substantially in the near-wall region, the averaged coefficients differ little from their values on the axis of the tube.…”

Section: Dust Particle Charging In the Stratified Glow Dischargementioning

confidence: 99%

Dust particle charging in a stratified glow discharge considering nonlocal electron kinetics

Golubovskiǐ

Karasev

Kartasheva

2017

Plasma Sources Sci. Technol.

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Dusty plasma has been studied in dc glow discharge with standing striation formed in neon. The theoretical method of dust particle charge determination is proposed. This method is based on the calculation of the ion and electron fluxes on the dust particle surface in a spatially periodic field of striation. The electron flux is calculated through the use of non-local electron energy distribution function (EEDF), which is formed by inhomogeneous strata potential. The calculation of dust particle charge using proposed theoretical method are compared with those in which the used EEDF was assumed to be Maxwell EEDF. Under the conditions of standing P-striations at low pressures of neon the numerical calculations and the measurements are performed. An experimental method of dust particle charge determination is applied in the dc discharge condition. Discharge current is modulated at low-frequency in order to determine the dust charge through the relaxation oscillation of a single dust particle. The calculation of the dust particle charge with the help of measured frequency and damping coefficient of the oscillations is made. The dust particle charges obtained by using two independent methods are in good agreement.

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Section: Dust Particle Charging In the Stratified Glow Dischargementioning

confidence: 99%

Dust particle charging in a stratified glow discharge considering nonlocal electron kinetics

Golubovskiǐ

Karasev

Kartasheva

2017

Plasma Sources Sci. Technol.

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“…However, in [22], equation (14) was obtained for a local approximation, as terms with spatial gradients were not considered when deriving equation (14). Conversely, numerous studies [15,[23][24][25][26][27][28][29][30][31] have revealed that at low pressures, for electrons with energies below the wall potential e , w j the EDF depends only on the total energy ε, even in the inelastic energy range. Thus, equation (14) cannot remain in a nonlocal mode with a non-uniform profile of N m .…”

Section: Resultsmentioning

confidence: 99%

“…) is strongly compressed to the axis and declines as it approaches the periphery. A peaked profile of reaction rate constants for an electron-induced process with a large energy threshold is characteristic of a nonlocal EDF [23][24][25][26][27].…”

Section: Resultsmentioning

confidence: 99%

Influence of metastable atoms on the formation of nonlocal EDF, electron reaction rates, and transport coefficients in argon plasma

Yuan

Zhou

Yao

et al. 2019

Plasma Sources Sci. Technol.

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The influence of metastable atoms on formation of the nonlocal electron distribution function (EDF) and other characteristics of gas-discharge plasma in argon is investigated in this paper. Superelastic collisions of electrons with metastable atoms strongly affect the shape of the EDF, the behavior of reaction rate constants, and other plasma characteristics. An interesting phenomenon of EDF replication emerges with a period of excitation threshold; this effect can increase the rate constants of excitation and ionization processes by several orders of magnitude, especially at the periphery of the plasma volume. Thus, collisions between electrons and metastable atoms are important in the formation of a nonlocal EDF, and neglecting them can lead to large errors in calculations of plasma characteristics.

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“…where n ea ex and n ea i are excitation and ionization collision frequencies; U ex and U i are excitation and ionization threshold energy, and which are set as 11.72 eV and 15.6 eV, respectively, for argon plasma. The electron-neutral cross sections are from [34].…”

Section: Electron Collisions Terms For the Kinetic Equationmentioning

confidence: 99%

Theoretical research on the transport and ionization rate coefficients in glow discharge dusty plasma

Liang

2019

Plasma Sci. Technol.

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The electron kinetic model for investigating the transport and ionization rate coefficients of argon glow discharge dusty plasma is developed from the Boltzmann equation. Both of the electronneutral and electron-dust collisions are considered as collision terms in the kinetic equation. The kinetic equation is simplified by employing the local approximation and nonlocal approach under the same discharge conditions, and the corresponding simplified kinetic equations are known as local and nonlocal kinetic equations respectively. Then the electron energy distribution function (EEDF) is obtained by numerically solving the local and nonlocal kinetic equations and the dust charging equations simultaneously. Based on the obtained EEDFs, the effective electron temperature, electron mobility, electron diffusion coefficient and ionization rate coefficient are calculated for different discharge conditions. It is shown that the EEDFs calculated from the local kinetic model clearly differ from the nonlocal EEDFs and both the local and nonlocal EEDFs are also clearly different with Maxwellian distributions. The appearance of dust particles results in an obvious decrease of high energy electrons and increase of low energy electrons when axial electric field is low. With the increase of axial electric field, the influence of dust particles on the EEDFs becomes smaller. The electron mobility and diffusion coefficients calculated on the basis of local and nonlocal EEDFs do not differ greatly to the dust-free ones. While, when dust density n d =10 6 cm −3 , the electron mobility increases obviously compared with the dust-free results at low axial electric field and decreases with the increasing axial electric field until they are close to the dust-free ones. Meanwhile, electron diffusion coefficients for dusty case become smaller and decrease with the increasing axial electric field. The ionization rate coefficients decrease when dust particles are introduced and they approach the dust-free results gradually with the increasing axial electric field.

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Diffusion-path approximation in nonlocal electron kinetics

Cited by 7 publications

References 12 publications

Dust particle charging in a stratified glow discharge considering nonlocal electron kinetics

Dust particle charging in a stratified glow discharge considering nonlocal electron kinetics

Influence of metastable atoms on the formation of nonlocal EDF, electron reaction rates, and transport coefficients in argon plasma

Theoretical research on the transport and ionization rate coefficients in glow discharge dusty plasma

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