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Title: Analysis of non-equilibrium phenomena in inductively coupled plasma generators

ORCiD logo [1];  [2];  [1]
  1. University of Illinois at Urbana-Champaign, Urbana, Illinois 61822, USA
  2. Von Karman Institute for Fluid Dynamics, Rhode-Saint-Genèse, Belgium
Publication Date:
Sponsoring Org.:
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 7; Related Information: CHORUS Timestamp: 2018-03-09 12:30:26; Journal ID: ISSN 1070-664X
American Institute of Physics
Country of Publication:
United States

Citation Formats

Zhang, W., Lani, A., and Panesi, M. Analysis of non-equilibrium phenomena in inductively coupled plasma generators. United States: N. p., 2016. Web. doi:10.1063/1.4958326.
Zhang, W., Lani, A., & Panesi, M. Analysis of non-equilibrium phenomena in inductively coupled plasma generators. United States. doi:10.1063/1.4958326.
Zhang, W., Lani, A., and Panesi, M. Mon . "Analysis of non-equilibrium phenomena in inductively coupled plasma generators". United States. doi:10.1063/1.4958326.
title = {Analysis of non-equilibrium phenomena in inductively coupled plasma generators},
author = {Zhang, W. and Lani, A. and Panesi, M.},
abstractNote = {},
doi = {10.1063/1.4958326},
journal = {Physics of Plasmas},
number = 7,
volume = 23,
place = {United States},
year = {Mon Jul 18 00:00:00 EDT 2016},
month = {Mon Jul 18 00:00:00 EDT 2016}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4958326

Citation Metrics:
Cited by: 4works
Citation information provided by
Web of Science

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  • This work addresses the modeling of non-equilibrium phenomena in inductively coupled plasma discharges. In the proposed computational model, the electromagnetic induction equation is solved together with the set of Navier-Stokes equations in order to compute the electromagnetic and flow fields, accounting for their mutual interaction. Semi-classical statistical thermodynamics is used to determine the plasma thermodynamic properties, while transport properties are obtained from kinetic principles, with the method of Chapman and Enskog. Particle ambipolar diffusive fluxes are found by solving the Stefan-Maxwell equations with a simple iterative method. Two physico-mathematical formulations are used to model the chemical reaction processes: (1) Amore » Local Thermodynamics Equilibrium (LTE) formulation and (2) a thermo-chemical non-equilibrium (TCNEQ) formulation. In the TCNEQ model, thermal non-equilibrium between the translational energy mode of the gas and the vibrational energy mode of individual molecules is accounted for. The electronic states of the chemical species are assumed in equilibrium with the vibrational temperature, whereas the rotational energy mode is assumed to be equilibrated with translation. Three different physical models are used to account for the coupling of chemistry and energy transfer processes. Numerical simulations obtained with the LTE and TCNEQ formulations are used to characterize the extent of non-equilibrium of the flow inside the Plasmatron facility at the von Karman Institute. Each model was tested using different kinetic mechanisms to assess the sensitivity of the results to variations in the reaction parameters. A comparison of temperatures and composition profiles at the outlet of the torch demonstrates that the flow is in non-equilibrium for operating conditions characterized by pressures below 30 000 Pa, frequency 0.37 MHz, input power 80 kW, and mass flow 8 g/s.« less
  • The objective of the present work is the development of a tightly coupled magneto-hydrodynamic model for inductively coupled radio-frequency plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State approach. A multi-temperature formulation is used to account for thermal non-equilibrium between translation of heavy-particles and vibration of molecules. Excited electronic states of atoms are instead treated as separate pseudo-species, allowing for non-Boltzmann distributions of their populations. Free-electrons are assumed Maxwellian at their own temperature. The governing equations for the electro-magnetic field and the gas properties (e.g., chemical composition and temperatures) are written as a coupled systemmore » of time-dependent conservation laws. Steady-state solutions are obtained by means of an implicit Finite Volume method. The results obtained in both LTE and NLTE conditions over a broad spectrum of operating conditions demonstrate the robustness of the proposed coupled numerical method. The analysis of chemical composition and temperature distributions along the torch radius shows that: (i) the use of the LTE assumption may lead to an inaccurate prediction of the thermo-chemical state of the gas, and (ii) non-equilibrium phenomena play a significant role close the walls, due to the combined effects of Ohmic heating and macroscopic gradients.« less
  • A time-dependent two-temperature model is developed to simulate the behavior of an argon radio frequency plasma under transient nonequilibrium conditions, with emphasis to shed light on the temporal and spatial evolution of the nonequilibrium phenomena occurring in pulsed power plasmas. The results show that the effects of changes in input power on the thermal nonequilibrium and the ionization nonequilibrium are most noticeable at the early stages of pulse on and off. The observed deviation from thermal equilibrium during pulsation is more pronounced in the fringes of the plasma and near the wall of the torch. In the central region, themore » influence is less significant and the plasma remains in a quasilocal thermal equilibrium state. The temporal evolution of the ionization nonequilibrium does not keep pace with that of the thermal nonequilibrium, and the relaxation process of the electron number density is slower and smoother. The effects of operating conditions on the transient behavior of the nonequilibrium situations under pulsed power conditions are also examined. It indicates that, for materials processing, a pulse duration between 2 and 10 ms is adequate for rf plasmas operated in pulse-modulated modes.« less
  • Large KROT device is developed for modeling of space plasma physics phenomena and studies of interaction of super-strong electromagnetic radiation with plasmas. The core of the facility is pulsed RF plasma source with MW power level. Well repeated and highly uniform plasma, magnetized or not, can be produced in a volume of several tens of cubic meters. An overview of the facility operational parameters is presented along with the results of recent experiments.
  • The technique of inductively coupled Plasma-Atomic Emission Spectroscopy (ICP) has been used for determining the equilibrium constants of organophosphorus extractants in liquid-liquid extraction systems. The 213.618 nm first order atomic emission line of phosphorus was monitored to determine the equilibrium constants. The relevant equilibrium constants of bis(2,4,4-trimethylpentyl)phosphinic acid, bis(2-ethylhexyl)phosphoric acid, diphenylphosphinic acid, trioctylphosphine oxide and tri-n-butylphosphate have been determined in this manner. It has been demonstrated for the first time that the equilibrium constants for liquid-liquid extractants can be determined in a facile manner using ICP. 14 references, 1 figure, 1 table.