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

Abstract

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.

Theoretical and experimental aspects of non-equilibrium plasmas in different regimes: fundamentals and selected applications

“…This model, determining at the same time the eedf and the thermodynamic state of the plasma, allows to consider variations in the plasma composition, electron-electron collisions and electron-induced processes from excited states of atoms and molecules. This approach has been applied to atomic systems [93][94][95], to molecular plasmas [96][97][98][99][100], also to evaluate the effects of using complete sets of vibrationally resolved cross sections [101,102], and to complex mixtures [103][104][105][106].…”

Features of the EEDF formation in the dusty plasma of the positive column of a glow discharge

“…In the Holstein-Tsendin model, the nonlocal EEDF depends on only one variable, namely the total energy ; thus, the kinetic equation after volume-averaging has the same form for the local approximation (see below equations ( 9) and ( 13)). This made it possible to implement [26][27][28][29][30] the adaptation procedure of the standard local Boltzmann solver to obtain a nonlocal EEDF using the Holstein-Tsendin method [19,24]. As a result, it has been possible to significantly expand the applicability of well-known software packages [29][30][31][32] available to a wide range of users for modeling of the EEDF in gas-discharge plasma and leading to an improvement of the obtained results.…”

“…In the present work, the effect of dust particles on the formation of the nonlocal EEDF in the positive column of the glow discharge in argon is investigated. It is based on the previous studies [26][27][28] on the influences of various processes on the formation of the nonlocal EEDF. The technique of adapting a standard local Boltzmann solver for the calculation of the nonlocal EEDF in dusty plasma is implemented.…”

On the relevance of superelastic collisions in argon and nitrogen discharges

“…The SC-StS approach has been applied to nitrogen [35], hydrogen [36] and nitrogen-hydrogen mixture [18] to evaluate the effects of using complete sets of vibrationally-resolved cross sections in affecting the dissociation and ionization kinetics in different discharges. The SC-StS approach is widely used in the community and different papers have been published to model different features of discharges in argon [37][38][39], nitrogen [40,41], air [42][43][44] and more complex mixtures [45][46][47]. Recently, a Round Robin [48] activity has been carried out for the verification of the plasma kinetic codes used by different research groups, trying to rationalize the discrepancies.…”