Gas temperature determination in an argon non-thermal plasma at atmospheric pressure from broadenings of atomic emission lines (original) (raw)
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Advances in Physics: X
This paper describes the use of Optical Emission Spectroscopy (OES) to measure electron densities and temperatures in nonequilibrium plasmas. The ways to interpret relative lineintensities of neutral argon atoms are evaluated based upon a collisional-radiative model including atomic collisional processes. A conversion from an excitation temperature determined from relative line intensities assuming a Boltzmann population distribution to the thermal electron temperature in the electron temperature range 1-4 eV and electron density range 10 10-10 12 cm-3 is given. Procedures to obtain electron temperature T e and density N e of non-equilibrium argon plasma by OES measurement with collisional radiative model.
Plasma Processes and Polymers, 2014
The electron temperature in atmospheric argon plasmas created by a DBD jet is determined using a combination of Absolute Line Intensity (ALI) measurements and a collisional radiative model (CRM). The ALI measurements have been performed to determine the densities of the states in the 4p level. In addition, the ground state density is taken into account, which is found via the pressure and the gas temperature. The density ratio of the ground state and 4p state gives a value of the excitation temperature, which by means of the CRM is transformed into the electron temperature. With this method, the electron temperature in the active zone of a pure argon plasma is found to be 1.27 eV which is significantly higher than the experimental value reported by others. An error analysis shows that the relative error in the electron temperature obtained in this way is about 5%. In the afterglow, the temperature decreases gradually to about 0.88 eV. The addition of 2% O 2 leads to a decrease in electron temperature of about 5%.
Journal of Applied Physics, 2006
The measurement of the electron mean kinetic energy by identifying the electron temperature and the excitation temperature obtained by optical emission spectroscopy is theoretically studied for two temperature argon plasmas at atmospheric pressure. Using a 32-level collisional radiative model in which both electron impact and argon-impact inelastic collisions are taken into account, it has been found that under certain conditions the argon inelastic collisions may cause a decrease of the argon excitation temperature so that the relation T e Ͼ T exc Ͼ T 0 is satisfied. This inequality also appears when electron losses due to diffusion are important and the electron density is lower than its equilibrium value.
Plasma Chemistry and Plasma Processing, 1990
Experimental measurements and computed results are reported on a nontransferred argon plasma discharging into an argon environment in a laminar regime. The experimental data provide information on the temperature profiles, particularly those close to the torch exit. The mathematical representation of the system involves the simultaneous statement of the equations of continuity, motion, and thermal energy balance for an axisymmetric system, but for fully temperature-dependent property values. On the whole, the theoretical predictions are in very good agreement with the measurements, with the maximum discrepancy being of the order of 5–10%. This augurs well for the extension of this work to more complex systems, also including gas mixtures.
Spectrochimica Acta Part B Atomic Spectroscopy
The densities of metastable and resonant states of Ar atoms are measured in high pressure Ar radio frequency discharge. Resonant absorption spectroscopy for the case of a low pressure spectral lamp and high-pressure plasma absorption lines is implemented for this purpose. The necessary generalizations for the high-pressure resonant absorption method are given. Absolute density of Ar 1s levels obtained at different RF input power and operating pressures are of the order of 1011 cm- 3, which is in a good agreement with those reported in the literature. The population distribution on the Ar 2p (exited) levels, obtained from the optical emission spectroscopy, reveals strong deviation from thermal equilibrium for these levels in the high-pressure case. The generation of the Ar excited states in the studied discharges is compared to the previously reported results.
Spectroscopy of heliumlike argon resonance and satellite lines for plasma temperature diagnostics
Physical review. E, Statistical, nonlinear, and soft matter physics, 2002
The n=2-1 spectral emission pattern of heliumlike argon, together with the associated satellite emission originating from lithiumlike argon have been measured with high-resolution x-ray spectroscopy at the Berlin electron-beam ion trap. The observed line intensity across a wide range of excitation energies was weighted by an electron-energy distribution to analyze as a function of plasma temperature the line ratios between KLL dielectronic recombination satellites, in particular the j+z, j, and k satellites, and the w-resonance line. A good agreement between various theoretical models is found, supporting the method of line-ratio measurement as a temperature diagnostic for plasmas. A value for the so-called R-line ratio is determined and calculations with the HULLAC suite of codes predict it to be electron density independent over a wide range.
Contributions to Plasma Physics, 2001
The present paper describes a spectroscopic method for determining electron temperature T e and density N e in an argon plasma jet on the basis of a Collisional-Radiative model of argon. Electron temperature and density in the argon plasma were measured by the method developed, and comparison of them was discussed with those obtained with a Langmuir probe. The results for T e and N e obtained by the spectroscopic method agreed roughly with those by the probe.
Plasma Sources Science and Technology, 2011
The aim of the paper is to test the accuracy of classical spectroscopic methods in the visible domain dedicated to measurements of temperature and electron density in order to conclude about the validity of thermal disequilibrium. The influence of various factors is studied: accuracy of the intensity calibration, Abel inversion of the experimental spectra, excitation temperature deduced from the relative method, absolute excitation temperature, influence of the transition probability accuracy, influence of the Biberman factor value, electron temperature from the line-to-continuum intensity ratio, electron density deduced from Stark broadening, and electron density deduced from the continuum intensity. This spectroscopic investigation is carried out for argon plasma and argon copper plasma both produced by means of an ICP torch operating at atmospheric pressure. Results are given with uncertainties for each evaluated parameter. We show that, first, the electron temperature deduced from the line-to-continuum intensity ratio has to be considered with great care; second, for argon plasma no evidence of thermal disequilibrium can be discerned, whereas for argon copper plasma a small disequilibrium of 1.2 to 1.4 at most is experimentally observed.