Local thermodynamic equilibrium in an RF argon plasma

A study has been made on transient extinction conditions in an inductively heated argon plasma. It was observed that local thermodynamic equilibrium (LTE) conditions do exist between the metastable 3P2 level and upper energy levels, so that during the decay time it is possible to determine a meaningful temperature, using the 3P2 level as a fundamental level and the partition functions being calculated accordingly. Together with the temperature determination, a concentration distribution of argon metastables was obtained.Studies of this type are useful for the investigation of quenching processes in plasmas, affecting favorably chemical reactions or solid–gas interactions, thus leading to enhanced catalytic effects or modifications of solid particle structures which are liable to generate new electrical, thermal, etc. properties of interest.

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A Comparison of Various NLTE Codes in Computing the Charge-State Populations of an Argon Plasma

International Astronomical Union Colloquium ◽

10.1017/s0252921100085420 ◽

1984 ◽

Vol 86 ◽

pp. 108-109

Author(s):

Sam R. Stone ◽

Jon C. Weisheit

Keyword(s):

Steady State ◽

Charge State ◽

Thermodynamic Equilibrium ◽

Local Thermodynamic Equilibrium ◽

Argon Plasma ◽

Computational Physics ◽

Photon Flux ◽

Easy Problem ◽

Computer Codes ◽

Bound Electrons

A comparison among nine computer codes shows surprisingly large differences where it had been believed that the computational physics was well understood. The codes simulate a plasma that is in steady state but not in local thermodynamic equilibrium (NLTE codes). In this study each code treats an “easy” problem, which is an argon plasma, optically thin and with no external photon flux; densities are varied from near-coronal to an intermediate 1021 electrons/cc and above. The temperatures are high enough that most ions have two or fewer bound electrons, which for this plasma means temperatures above about 300 eV.The present study asks only if the codes compute similar charge-state populations (a surprising “no”), and, if not, why not. It does not claim accuracy for any code either by comparison to experiment or by appeal to a concensus.

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The radiative transfer of impact broadened spectral lines emitted by an argon plasma described by the local thermodynamic equilibrium appproximation

Proceedings of the Physical Society ◽

10.1088/0370-1328/85/6/325 ◽

1965 ◽

Vol 85 (6) ◽

pp. 1261-1268 ◽

Cited By ~ 6

Author(s):

D D Burgess ◽

J Cooper

Keyword(s):

Radiative Transfer ◽

Thermodynamic Equilibrium ◽

Local Thermodynamic Equilibrium ◽

Argon Plasma ◽

Spectral Lines

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An investigation of local thermodynamic equilibrium in an argon plasma jet at atmospheric pressure

Journal of Quantitative Spectroscopy and Radiative Transfer ◽

10.1016/0022-4073(89)90067-8 ◽

1989 ◽

Vol 41 (5) ◽

pp. 369-376 ◽

Cited By ~ 17

Author(s):

Vivek Bakshi ◽

Robert J. Kearney

Keyword(s):

Thermodynamic Equilibrium ◽

Atmospheric Pressure ◽

Local Thermodynamic Equilibrium ◽

Argon Plasma ◽

Plasma Jet ◽

Argon Plasma Jet

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Blackbody Radiation, Boltzmann Statistics, Temperature, and Thermodynamic Equilibrium

10.1093/oso/9780199662104.003.0003 ◽

2017 ◽

Author(s):

Kelly Chance ◽

Randall V. Martin

Keyword(s):

Thermodynamic Equilibrium ◽

Local Thermodynamic Equilibrium ◽

Photophysical Properties ◽

Blackbody Radiation ◽

Boltzmann Constant ◽

Noise Sources ◽

Atmospheric Molecules ◽

Tightly Coupled ◽

Boltzmann Statistics ◽

Planck’S Law

Blackbody radiation, temperature, and thermodynamic equilibrium give a tightly coupled description of systems (atmospheres, volumes, surfaces) that obey Boltzmann statistics. They provide descriptions of systems when Boltzmann statistics apply, either approximately or nearly exactly. These apply most of the time in the Earth’s stratosphere and troposphere, and in other planetary atmospheres as long as the density is sufficient that collisions among atmospheric molecules, rather than photochemical and photophysical properties, determine the energy populations of the ensemble of molecules. Thermodynamic equilibrium and the approximation of local thermodynamic equilibrium are introduced. Boltzmann statistics, blackbody radiation, and Planck’s law are described. The chapter introduces the Rayleigh-Jeans limit, description of noise sources as temperatures, Kirchoff’s law, the Stefan-Boltzmann constant, and Wien’s law.

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