Application of the Generalized Theory of Stark Broadening to Experimental Highly-Excited Balmer Lines from a Radio-Frequency Discharge

Oks, Eugene; Bengtson, Roger D.; Touma, J.

doi:10.1002/(sici)1521-3986(200004)40:1/2<158::aid-ctpp158>3.0.co;2-w

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…One example that is discussed in paper [59] was HHSL that was emitted from edge plasmas of tokamaks. In laboratory plasmas, HHSL are used for measuring the electron density at the edge plasmas of tokamaks (see, e.g., papers [60,61] and Section 4.3 of review [62]) and in radiofrequency discharges (see, e.g., paper [63] and book [5]).…”

Section: Preamblementioning

confidence: 99%

Review of Recent Advances in the Analytical Theory of Stark Broadening of Hydrogenic Spectral Lines in Plasmas: Applications to Laboratory Discharges and Astrophysical Objects

Oks

2018

Atoms

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There is presented an overview of the latest advances in the analytical theory of Stark broadening of hydrogenic spectral lines in various types of laboratory and astrophysical plasmas. They include: (1) advanced analytical treatment of the Stark broadening of hydrogenic spectral lines by plasma electrons; (2) center-of-mass effects for hydrogen atoms in a nonuniform electric field: applications to magnetic fusion, radiofrequency discharges, and flare stars; (3) penetrating-ions-caused shift of hydrogenic spectral lines in plasmas; (4) improvement of the method for measuring the electron density based on the asymmetry of hydrogenic spectral lines in dense plasmas; (5) Lorentz–Doppler broadening of hydrogen/deuterium spectral lines: analytical solution for any angle of observation and any magnetic field strength, and its applications to magnetic fusion and solar physics; (6) Revision of the Inglis-Teller diagnostic method; (7) Stark broadening of hydrogen/deuterium spectral lines by a relativistic electron beam: analytical results and applications to magnetic fusion; (8) Influence of magnetic-field-caused modifications of the trajectories of plasma electrons on shifts and relative intensities of Zeeman components of hydrogen/deuterium spectral lines: applications to magnetic fusion and white dwarfs; (9) Influence of magnetic-field-caused modifications of trajectories of plasma electrons on the width of hydrogen/deuterium spectral lines: applications to white dwarfs; (10) Stark broadening of hydrogen lines in plasmas of electron densities up to or more than Ne~1020 cm−3; and, (11) The shape of spectral lines of two-electron Rydberg atoms/ions: a peculiar Stark broadening.

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Section: Preamblementioning

confidence: 99%

Review of Recent Advances in the Analytical Theory of Stark Broadening of Hydrogenic Spectral Lines in Plasmas: Applications to Laboratory Discharges and Astrophysical Objects

Oks

2018

Atoms

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“…One example discussed in paper [1] was HHSL emitted from edge plasmas of tokamaks. In laboratory plasmas, HHSL are used for measuring the electron density at the edge plasmas of tokamaks (see, e.g., papers [2,3] and section 4.3 of review [4]) and in radiofrequency discharges (see, e.g., paper [5] and book [6]).…”

Section: Introductionmentioning

confidence: 99%

Lorentz–Doppler profiles of hydrogen/deuterium lines for magnetic fusion: analytical solution for any angle of observation and any magnetic field strength

Sanders

Oks

2017

J. Phys. Commun.

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We extend the analytical results for the Lorentz-Doppler profiles of highly-excited hydrogen/ deuterium spectral lines for the arbitrary strength of the magnetic field B, obtained in a paper by one of us, Oks (2015 J. Quant. Spectr. Rad. Transfer 156 24), for observations parallel or perpendicular with respect to B, to arbitrary angles of the observation ψ. We study the evolution of the effect of the suppression of the π-components (compared to the σ-components) as the angle of the observation ψ decreases from 90°, i.e., as ψ decreases from the value, at which this counterintuitive effect was discovered in the paper quoted above. We show that the suppression of the π-components (compared to the σ-components) occurs at the perpendicular or close to the perpendicular direction of observation (with respect to the magnetic field B), but disappears at lower values of the angle of the observation. Our results should be important, e.g., for spectroscopic diagnostics of edge plasmas of various magnetic fusion devices around the world. Another finding is that the width of the Lorentz-Doppler profiles is a non-monotonic function of the magnetic field for observations perpendicular to B, which is yet another counterintuitive result.

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Influence of excited state spatial distributions on plasma diagnostics: Atmospheric pressure laser-induced He-H2 plasma

Monfared

Hüwel

2012

Journal of Applied Physics

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Atmospheric pressure plasmas in helium-hydrogen mixtures with H2 molar concentrations ranging from 0.13% to 19.7% were investigated at times from 1 to 25 μs after formation by a Q-switched Nd:YAG laser. Spatially integrated electron density values are obtained using time resolved optical emission spectroscopic techniques. Depending on mixture concentration and delay time, electron densities vary from almost 1017 cm−3 to about 1014 cm−3. Helium based results agree reasonably well with each other, as do values extracted from the Hα and Hβ emission lines. However, in particular for delays up to about 7 μs and in mixtures with less than 1% hydrogen, large discrepancies are observed between results obtained from the two species. Differences decrease with increasing hydrogen partial pressure and/or increasing delay time. In mixtures with molecular hydrogen fraction of 7% or more, all methods yield electron densities that are in good agreement. These findings seemingly contradict the well-established idea that addition of small amounts of hydrogen for diagnostic purposes does not perturb the plasma. Using Abel inversion analysis of the experimental data and a semi-empirical numerical model, we demonstrate that the major part of the detected discrepancies can be traced to differences in the spatial distributions of excited helium and hydrogen neutrals. The model yields spatially resolved emission intensities and electron density profiles that are in qualitative agreement with experiment. For the test case of a 1% H2 mixture at 5 μs delay, our model suggests that high electron temperatures cause an elevated degree of ionization and thus a reduction of excited hydrogen concentration relative to that of helium near the plasma center. As a result, spatially integrated analysis of hydrogen emission lines leads to oversampling of the plasma perimeter and thus to lower electron density values compared to those obtained from helium lines.

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Application of the Generalized Theory of Stark Broadening to Experimental Highly-Excited Balmer Lines from a Radio-Frequency Discharge

Cited by 4 publications

References 8 publications

Review of Recent Advances in the Analytical Theory of Stark Broadening of Hydrogenic Spectral Lines in Plasmas: Applications to Laboratory Discharges and Astrophysical Objects

Review of Recent Advances in the Analytical Theory of Stark Broadening of Hydrogenic Spectral Lines in Plasmas: Applications to Laboratory Discharges and Astrophysical Objects

Lorentz–Doppler profiles of hydrogen/deuterium lines for magnetic fusion: analytical solution for any angle of observation and any magnetic field strength

Influence of excited state spatial distributions on plasma diagnostics: Atmospheric pressure laser-induced He-H2 plasma

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