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Title: Stark broadening for diagnostics of the electron density in non-equilibrium plasma utilizing isotope hydrogen alpha lines

Abstract

Two Stark broadening parameters including FWHM (full width at half maximum) and FWHA (full width at half area) of isotope hydrogen alpha lines are simultaneously introduced to determine the electron density of a pulsed vacuum arc jet. To estimate the gas temperature, the rotational temperature of the C{sub 2} Swan system is fit to 2500 ± 100 K. A modified Boltzmann-plot method with b{sub i}-factor is introduced to determine the modified electron temperature. The comparison between results of atomic and ionic lines indicates the jet is in partial local thermodynamic equilibrium and the electron temperature is close to 13 000 ± 400 K. Based on the computational results of Gig-Card calculation, a simple and precise interpolation algorithm for the discrete-points tables can be constructed to obtain the traditional n{sub e}-T{sub e} diagnostic maps of two Stark broadening parameters. The results from FWHA formula by the direct use of FWHM = FWHA and these from the diagnostic map are different. It can be attributed to the imprecise FWHA formula form and the deviation between FWHM and FWHA. The variation of the reduced mass pair due to the non-equilibrium effect contributes to the difference of the results derived from two hydrogen isotope alpha lines. Based on the Stark broadening analysis inmore » this work, a corrected method is set up to determine n{sub e} of (1.10 ± 0.08) × 10{sup 21} m{sup −3}, the reference reduced mass μ{sub 0} pair of (3.30 ± 0.82 and 1.65 ± 0.41), and the ion kinetic temperature of 7900 ± 1800 K.« less

Authors:
 [1];  [2]; ; ; ; ;  [3];  [1]
  1. Institute of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China)
  2. (China)
  3. Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900 (China)
Publication Date:
OSTI Identifier:
22273484
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALGORITHMS; COMPARATIVE EVALUATIONS; ELECTRON DENSITY; ELECTRON TEMPERATURE; HYDROGEN ISOTOPES; INTERPOLATION; ION TEMPERATURE; LTE; NON-EQUILIBRIUM PLASMA; PLASMA JETS

Citation Formats

Yang, Lin, Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, Tan, Xiaohua, Wan, Xiang, Chen, Lei, Jin, Dazhi, Qian, Muyang, and Li, Gongping, E-mail: ligp@lzu.edu.cn. Stark broadening for diagnostics of the electron density in non-equilibrium plasma utilizing isotope hydrogen alpha lines. United States: N. p., 2014. Web. doi:10.1063/1.4873960.
Yang, Lin, Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, Tan, Xiaohua, Wan, Xiang, Chen, Lei, Jin, Dazhi, Qian, Muyang, & Li, Gongping, E-mail: ligp@lzu.edu.cn. Stark broadening for diagnostics of the electron density in non-equilibrium plasma utilizing isotope hydrogen alpha lines. United States. doi:10.1063/1.4873960.
Yang, Lin, Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, Tan, Xiaohua, Wan, Xiang, Chen, Lei, Jin, Dazhi, Qian, Muyang, and Li, Gongping, E-mail: ligp@lzu.edu.cn. 2014. "Stark broadening for diagnostics of the electron density in non-equilibrium plasma utilizing isotope hydrogen alpha lines". United States. doi:10.1063/1.4873960.
@article{osti_22273484,
title = {Stark broadening for diagnostics of the electron density in non-equilibrium plasma utilizing isotope hydrogen alpha lines},
author = {Yang, Lin and Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900 and Tan, Xiaohua and Wan, Xiang and Chen, Lei and Jin, Dazhi and Qian, Muyang and Li, Gongping, E-mail: ligp@lzu.edu.cn},
abstractNote = {Two Stark broadening parameters including FWHM (full width at half maximum) and FWHA (full width at half area) of isotope hydrogen alpha lines are simultaneously introduced to determine the electron density of a pulsed vacuum arc jet. To estimate the gas temperature, the rotational temperature of the C{sub 2} Swan system is fit to 2500 ± 100 K. A modified Boltzmann-plot method with b{sub i}-factor is introduced to determine the modified electron temperature. The comparison between results of atomic and ionic lines indicates the jet is in partial local thermodynamic equilibrium and the electron temperature is close to 13 000 ± 400 K. Based on the computational results of Gig-Card calculation, a simple and precise interpolation algorithm for the discrete-points tables can be constructed to obtain the traditional n{sub e}-T{sub e} diagnostic maps of two Stark broadening parameters. The results from FWHA formula by the direct use of FWHM = FWHA and these from the diagnostic map are different. It can be attributed to the imprecise FWHA formula form and the deviation between FWHM and FWHA. The variation of the reduced mass pair due to the non-equilibrium effect contributes to the difference of the results derived from two hydrogen isotope alpha lines. Based on the Stark broadening analysis in this work, a corrected method is set up to determine n{sub e} of (1.10 ± 0.08) × 10{sup 21} m{sup −3}, the reference reduced mass μ{sub 0} pair of (3.30 ± 0.82 and 1.65 ± 0.41), and the ion kinetic temperature of 7900 ± 1800 K.},
doi = {10.1063/1.4873960},
journal = {Journal of Applied Physics},
number = 16,
volume = 115,
place = {United States},
year = 2014,
month = 4
}
  • First observations are presented of the optically thin and reabsorption free-hydrogen resonance line Lyman-..cap alpha.., emitted from a dense equilibrium plasma (n/sub e/ approx. = 10/sup 23/ m/sup -3/, T/sub e/ approx. = 10/sup 4/ K). In the core of the line (wavelength range up to three half-widths) the Stark profiles are determined nearly exclusively by the central Stark component, which is broadened significantly more strongly than predicted by the theories. The experimental Ly-..cap alpha.. Stark widths are larger by a factor of about 2.5 than theoretical ones.
  • Results of plasma density measurements in ablative and hydrogen-filled discharge capillaries are presented. The method of plasma density measurement is based on Stark broadening of atomic hydrogen spectral lines in the plasma due to interaction of the hydrogen atoms with free charges. To ensure the measured plasma density corresponds to the internal portion of the discharge volume, we also examine a possibility to collect the plasma light emission with an optical fiber inserted inside the capillary channel. We studied the time dependence of the plasma density relative to the beginning of the discharge with a temporal resolution of 150 ns.more » The plasma density was found to vary over a range of 1017-1015 cm-3. The dependence of the plasma density upon discharge voltage and hydrogen pressure in the hydrogen-filled capillary was also studied. The possibility of designing a hybrid ablative hydrogen-filled capillary that allows us to simplify the high voltage generator scheme and reach high plasma densities is discussed.« less
  • We present results for Stark broadening of high principal quantum number (up to n=15) Balmer lines, using an analytical (the ''standard theory'') approach and two independently developed computer simulation methods. The line shapes are calculated for several sets of plasma parameters, applicable to radio-frequency discharge (N{sub e}{approx_equal}10{sup 13} cm{sup -3}) and magnetic fusion (N{sub e}{approx_equal}10{sup 15} cm{sup -3}) experiments. Comparisons of the calculated line profiles to the experimental data show a very good agreement. Density and temperature dependences of the linewidths, as well as relative contributions of different Stark-broadening mechanisms, are analyzed. It is seen that the standard theory ofmore » line broadening is sufficiently accurate for the entire set of plasma conditions and spectral transitions considered here, while an alternative theory (''advanced generalized theory'') is shown to be inadequate for the higher-density region. A discussion of possible reasons for this disagreement is given.« less