A volume averaged global model study of the influence of the electron energy distribution and the wall material on an oxygen discharge

Toneli, David; Pessoa, Rodrigo Sávio; Roberto, Marisa; Guðmundsson, Jón Tómas

doi:10.1088/0022-3727/48/49/495203

Cited by 17 publications

(18 citation statements)

References 48 publications

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“…Surface interactions are known to be important production and loss channels of RS and energy in low-temperature plasmas produced at low pressure [23][24][25][26]. However, the role of surface interactions in APPs is less well known.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the influence of surface reaction probabilities on reactive species in an rf atmospheric pressure plasma containing humidity

Schröter

Gibson

Kushner

et al. 2017

Plasma Phys. Control. Fusion

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The quantification and control of reactive species (RS) in atmospheric pressure plasmas (APPs) is of great interest for their technological applications, in particular in biomedicine. Of key importance in simulating the densities of these species are fundamental data on their production and destruction. In particular, data concerning particle-surface reaction probabilities in APPs are scarce, with most of these probabilities measured in low-pressure systems. In this work, the role of surface reaction probabilities, γ, of reactive neutral species (H, O and OH) on neutral particle densities in a He-H 2 O radio-frequency micro APP jet (COST-mAPPJ) are investigated using a global model. It is found that the choice of γ, particularly for low-mass species having large diffusivities, such as H, can change computed species densities significantly. The importance of γ even at elevated pressures offers potential for tailoring the RS composition of atmospheric pressure microplasmas by choosing different wall materials or plasma geometries.

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Section: Introductionmentioning

confidence: 99%

Numerical study of the influence of surface reaction probabilities on reactive species in an rf atmospheric pressure plasma containing humidity

Schröter

Gibson

Kushner

et al. 2017

Plasma Phys. Control. Fusion

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“…Further, limitations may be imposed based on assumptions regarding the EEDF, which cannot be obtained selfconsistently in global models, but can have a significant effect on the solution they produce. [109][110][111][112] A realistic representation of the EEDF can be obtained under highly collisional conditions where the electrons can be assumed to be in equilibrium with the local reduced electric field using a two-term-approximation Boltzmann equation solver such as Bolsigþ. [28] The pressure at which this assumption is valid is dependent upon the details of the electron impact cross sections for the gas to be modeled.…”

Section: Limitations and Pitfallsmentioning

confidence: 99%

Concepts, Capabilities, and Limitations of Global Models: A Review

Hurlbatt

Gibson

Schröter

et al. 2016

Plasma Processes & Polymers

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For researchers wishing to generate an understanding of complex plasma systems, global models often present an attractive first step, mainly due to their ease of development and use. These volume averaged models are able to give descriptions of plasmas with complex chemical kinetics, and without the computationally intensive numerical methods required for spatially resolved models. This paper gives a tutorial on global modeling, including development and techniques, and provides a discussion on the issues and pitfalls that researchers should be aware of. Further discussion is provided in the form of two reviews on methods of extending global modeling techniques to encompass variations in either time or space.

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“…Major contributions to the modelling of low pressure non-thermal oxygen plasmas have been made by, among others, the groups at Lisbon (Guerra and Loureiro 1995, 1999, Marinov et al 2013, Berkeley (Lee et al 1994, Lee andLieberman 1995), Reykjavík (Gudmundsson et al 2001, Gudmundsson 2004, Toneli et al 2015a, Toneli et al 2015b and different teams in Moscow (Ivanov et al 2003, Ionin et al 2007, Mankelevich et al 2016. An important approximation is related to the shape of the electron energy distribution function (EEDF) in these models.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of highly vibrationally excited O₂(X) molecules in inductively-coupled oxygen plasmas

Annusova¹,

Marinov²,

Booth³

et al. 2018

Plasma Sources Sci. Technol.

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The high degree of vibrational excitation of O 2 ground state molecules recently observed in inductively coupled plasma discharges is investigated experimentally in more detail and interpreted using a detailed self-consistent 0D global kinetic model for oxygen plasmas. Additional experimental results are presented and used to validate the model. The vibrational kinetics considers vibrational levels up to v=41 and accounts for electron impact excitation and de-excitation (e-V), vibration-to-translation relaxation (V-T) in collisions with O 2 molecules and O atoms, vibration-to-vibration energy exchanges (V-V), excitation of electronically excited states, dissociative electron attachment, and electron impact dissociation. Measurements were performed at pressures of 10-80 mTorr (1.33 and 10.67 Pa) and radio frequency (13.56 MHz) powers up to 500 W. The simulation results are compared with the absolute densities in each O 2 vibrational level obtained by high sensitivity absorption spectroscopy measurements of the Schumann-Runge bands for O 2 (X, v=4-18), O( 3 P) atom density measurements by two-photon absorption laser induced fluorescence (TALIF) calibrated against Xe, and laser photodetachment measurements of the O − negative ions. The highly excited O 2 (X, v) distribution exhibits a shape similar to a Treanor-Gordiets distribution, but its origin lies in electron impact e-V collisions and not in V-V up-pumping, in contrast to what happens in all other molecular gases known to date. The relaxation of vibrational quanta is mainly due to V-T energy-transfer collisions with O atoms and to electron impact dissociation of vibrationally excited molecules, e+O 2 (X, v)→O( 3 P)+O( 3 P).

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A volume averaged global model study of the influence of the electron energy distribution and the wall material on an oxygen discharge

Cited by 17 publications

References 48 publications

Numerical study of the influence of surface reaction probabilities on reactive species in an rf atmospheric pressure plasma containing humidity

Numerical study of the influence of surface reaction probabilities on reactive species in an rf atmospheric pressure plasma containing humidity

Concepts, Capabilities, and Limitations of Global Models: A Review

Kinetics of highly vibrationally excited O₂(X) molecules in inductively-coupled oxygen plasmas

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A volume averaged global model study of the influence of the electron energy distribution and the wall material on an oxygen discharge

Cited by 17 publications

References 48 publications

Numerical study of the influence of surface reaction probabilities on reactive species in an rf atmospheric pressure plasma containing humidity

Numerical study of the influence of surface reaction probabilities on reactive species in an rf atmospheric pressure plasma containing humidity

Concepts, Capabilities, and Limitations of Global Models: A Review

Kinetics of highly vibrationally excited O2(X) molecules in inductively-coupled oxygen plasmas

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Kinetics of highly vibrationally excited O₂(X) molecules in inductively-coupled oxygen plasmas