Wave driven N2–Ar discharge. I. Self-consistent theoretical model

Henriques, J.; Tatarova, E.; Guerra, Vasco; Ferreira, C. M.

doi:10.1063/1.1462842

Cited by 79 publications

(86 citation statements)

References 47 publications

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“…Here, is the ground state of the Ar atom, with denotes the levels of the configuration and denotes the levels of the configuration, with ,2,3,4 corresponding to the , , , levels, respectively. Details on the corresponding rate balance equations can be found in previous works [15]- [18]. Axial and radial diffusion losses of metastables are taken into consideration.…”

Section: Theoretical Modelmentioning

confidence: 99%

“…It is assumed that the density of the excited species is zero at and . The electron continuity equation accounts for the balance between the total rate of ionization and the total rate of electron losses due to diffusion to the wall and bulk recombination [16], [18]. The total rate of ionization is the sum of the contributions of ionization from the ground state and from the excited states by electron impact and of energy pooling reactions (R7,R8).…”

Section: Theoretical Modelmentioning

confidence: 99%

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A large-scale Ar plasma source excited by a TM/sub 330/ mode

Tatarova¹,

Dias²,

Henriques³

et al. 2005

IEEE Trans. Plasma Sci.

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This paper reports a theoretical and experimental study on the spatial structure of a large-scale, slot-antenna excited plasma source operating in Ar. The overdense plasma (with a plasma frequency pl higher than stimulating frequency ) close to the wave energy source sustained by the TM 330 surface mode is analyzed. A self-consistent theoretical model based on a set of coupled equations is developed, which includes the electron Boltzmann equation, the rate balance equations for the most important excited species and charged particles, the gas thermal balance equation, and the wave mode electrodynamic equations. The principal collisional and radiative processes that determine the populations in the Ar(3p 5 4s) and Ar(3p 5 4p) levels are accounted for. The model determines the three-dimensional discharge structure, i.e., the radial, azimuthal and axial variations of the main discharge quantities. An experimental validation of the model predictions is achieved using probe techniques and radiophysics methods. Strong correlations are shown to exist between the density distributions of plasma electrons, positive ions, and electronically excited states of Ar atoms and the electric field intensity distribution in the discharge zone of the plasma source.

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Section: Theoretical Modelmentioning

confidence: 99%

Section: Theoretical Modelmentioning

confidence: 99%

A large-scale Ar plasma source excited by a TM/sub 330/ mode

Tatarova¹,

Dias²,

Henriques³

et al. 2005

IEEE Trans. Plasma Sci.

Self Cite

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“…Given the fact that, under the conditions of interest, the main role of the electrons is to absorb microwave power and to transfer it to the heavy particles, we further assume δ = 0.9, which is a typical value for atmospheric pressure conditions, and ~10% energy in radiation and dielectric losses. The approach used has been validated in a series of extensive experimental and theoretical studies [34,[49][50][51][52][53][54].…”

Section: Theoretical Modelmentioning

confidence: 99%

On the plasma-based growth of ‘flowing’ graphene sheets at atmospheric pressure conditions

Цыганов

Bundaleska

Tatarova

et al. 2015

Plasma Sources Sci. Technol.

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A theoretical and experimental study on atmospheric pressure microwave plasma-based assembly of free standing graphene sheets is presented. The synthesis method is based on introducing a carbon-containing precursor (C 2 H 5 OH) through a microwave (2.45 GHz) argon plasma environment, where decomposition of ethanol molecules takes place and carbon atoms and molecules are created and then converted into solid carbon nuclei in the 'colder' nucleation zones. A theoretical model previously developed has been further updated and refined to map the particle and thermal fluxes in the plasma reactor. Considering the nucleation process as a delicate interplay between thermodynamic and kinetic factors, the model is based on a set of non-linear differential equations describing plasma thermodynamics and chemical kinetics. The model predictions were validated by experimental results. Optical emission spectroscopy was applied to detect the plasma emission related to carbon species from the 'hot' plasma zone. Raman spectroscopy, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS) techniques have been applied to analyze the synthesized nanostructures. The microstructural features of the solid carbon nuclei collected from the colder zones of plasma reactor vary according to their location. A part of the solid carbon was deposited on the discharge tube wall. The solid assembled from the main stream, which was gradually withdrawn from the hot plasma region in the outlet plasma stream directed to a filter, was composed by 'flowing' graphene sheets. The influence of additional hydrogen, Ar flow rate and microwave power on the concentration of obtained stable species and carbon−dicarbon was evaluated. The ratio of sp 3 /sp 2 carbons in graphene sheets is presented. A correlation between changes in C 2 and C number densities and sp 3 /sp 2 ratio was found.

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“…Meanwhile, the NH emission can be magnified with the addition of N2. The effects of the additive N2 on the Ar plasma kinetics in a gaseous system have been previously investigated, both theoretically [33,34] and experimentally [30]. In an Ar-N2 gas mixture, a plasma generates nitrogen species, such as N, N2 * , and N2 + , in various excited levels in addition to Ar * and Ar + .…”

Section: Fig 10 Plasma Optical Emission Spectra In a Range Of 300-4mentioning

confidence: 99%