Transient conditions in inductively heated plasmas: thermodynamic equilibrium and temperature measurements

1982 ◽  
Vol 60 (6) ◽  
pp. 886-892 ◽  
Author(s):  
Paul Meubus
Keyword(s):  
Thermodynamic Equilibrium ◽  
Decay Time ◽  
Concentration Distribution ◽  
Local Thermodynamic Equilibrium ◽  
Energy Levels ◽  
Argon Plasma ◽  
Partition Functions ◽  
Transient Conditions ◽  
Gas Interactions ◽  
Catalytic Effects

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.

scholarly journals Calculation of the ionization state for LTE plasmas using analytical potentials

1999 ◽  
Vol 17 (4) ◽  
pp. 635-647 ◽  
Author(s):  
J.G. RUBIANO ◽  
R. RODRÍGUEZ ◽  
J.M. GIL ◽  
P. MARTEL ◽  
E. MÍNGUEZ
Keyword(s):  
Thermodynamic Equilibrium ◽  
Local Thermodynamic Equilibrium ◽  
Atomic Data ◽  
Partition Functions ◽  
Ionization State ◽  
Saha Equation ◽  
Analytical Potential ◽  
Plasma Effects

In this work, the Saha equation is solved using atomic data provided by means of analytical potentials to calculate the ionization state and ion abundances for local thermodynamic equilibrium (LTE) plasmas of Al, Fe, and Au. The plasma effects are taking into account using an analytical potential which includes plasma effects. The problem of the cut off partition functions in the Saha equation is also analyzed using three different criteria. Finally, some opacity calculations are performed.

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

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.

Atomic collisions and local thermodynamic equilibrium in stellar atmospheres

1968 ◽  
Vol 306 (1484) ◽  
pp. 91-118 ◽  
Keyword(s):  
Thermodynamic Equilibrium ◽  
Local Thermodynamic Equilibrium ◽  
Energy Levels ◽  
Stellar Atmospheres ◽  
Emission Lines ◽  
Hot Stars ◽  
Atomic Collisions ◽  
To Come ◽  
Atomic Energy Levels

Theoretical and observational evidence for the role of collisions with electrons and neutral atoms in establishing the populations of atomic energy levels in stellar atmospheres are reviewed, with special reference to the problem of defining the range of validity of the approximation of local thermodynamic equilibrium. The discussion refers to stellar continuous spectra, absorption lines and emission lines believed to come from extended envelopes, surrounding certain hot stars.

Blackbody Radiation, Boltzmann Statistics, Temperature, and Thermodynamic Equilibrium

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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