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Title: Time dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U

Abstract

Helium line-ratios for electron temperature (Te) and density (ne) plasma diagnostic in the Scrape-Off-Layer (SOL) and Edge regions of tokamaks are widely used. Due to their intensities and proximity of wavelengths, the singlet 667.8 and 728.1 nm, and triplet 706.5 nm visible lines have been typically preferred. Time- dependency of the triplet line (706.5 nm) has been previously analyzed in detail by including transient effects on line-ratios during gas-puff diagnostic applications. In this work, several line-ratio combinations within each of the two spin systems are analyzed with the purpose of eliminating transient effects to extend the application of this powerful diagnostic to high temporal resolution characterization of plasmas. The analysis is done using synthetic emission modeling and diagnostic for low electron density NSTX SOL plasma conditions for several visible lines. This analysis employs both quasi-static equilibrium and time-dependent models in order to evaluate transient effects of the atomic population levels that may affect the derived electron temperatures and densities as a helium gas-puff penetrates the plasma. Ratios between the most intense lines are usually preferred due to their higher signal to noise ratio. The analysis of a wider range of spectral lines will help to extend this powerful diagnostic tomore » experiments where the wavelength range of the measured spectra may be constrained either by limitations of the spectrometer, or by other conflicting lines from different ions.« less

Authors:
ORCiD logo ; ; ; ;
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
DOE Contract Number:  
AC02-09CH11466
Product Type:
Dataset
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Keywords:
Scrape-Off-Layer (SOL); Ion Cyclotron Resonant Heating (ICRH); Hybrid-Time-Dependent/Independent (HTD/I)
OSTI Identifier:
1366719
DOI:
10.11578/1366719

Citation Formats

Bergos, J. M., Barbui, T., Schmitz, O., Stutman, D., and Tritz, K. Time dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U. United States: N. p., 2016. Web. doi:10.11578/1366719.
Bergos, J. M., Barbui, T., Schmitz, O., Stutman, D., & Tritz, K. Time dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U. United States. doi:10.11578/1366719.
Bergos, J. M., Barbui, T., Schmitz, O., Stutman, D., and Tritz, K. 2016. "Time dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U". United States. doi:10.11578/1366719. https://www.osti.gov/servlets/purl/1366719. Pub date:Tue Nov 01 00:00:00 EDT 2016
@article{osti_1366719,
title = {Time dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U},
author = {Bergos, J. M. and Barbui, T. and Schmitz, O. and Stutman, D. and Tritz, K.},
abstractNote = {Helium line-ratios for electron temperature (Te) and density (ne) plasma diagnostic in the Scrape-Off-Layer (SOL) and Edge regions of tokamaks are widely used. Due to their intensities and proximity of wavelengths, the singlet 667.8 and 728.1 nm, and triplet 706.5 nm visible lines have been typically preferred. Time- dependency of the triplet line (706.5 nm) has been previously analyzed in detail by including transient effects on line-ratios during gas-puff diagnostic applications. In this work, several line-ratio combinations within each of the two spin systems are analyzed with the purpose of eliminating transient effects to extend the application of this powerful diagnostic to high temporal resolution characterization of plasmas. The analysis is done using synthetic emission modeling and diagnostic for low electron density NSTX SOL plasma conditions for several visible lines. This analysis employs both quasi-static equilibrium and time-dependent models in order to evaluate transient effects of the atomic population levels that may affect the derived electron temperatures and densities as a helium gas-puff penetrates the plasma. Ratios between the most intense lines are usually preferred due to their higher signal to noise ratio. The analysis of a wider range of spectral lines will help to extend this powerful diagnostic to experiments where the wavelength range of the measured spectra may be constrained either by limitations of the spectrometer, or by other conflicting lines from different ions.},
doi = {10.11578/1366719},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2016},
month = {11}
}

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Works referenced in this record:

Time-dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U
journal, July 2016

  • Muñoz Burgos, J. M.; Barbui, T.; Schmitz, O.
  • Review of Scientific Instruments, Vol. 87, Issue 11
  • DOI: 10.1063/1.4955286

    Works referencing / citing this record:

    Time-dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U
    journal, July 2016

    • Muñoz Burgos, J. M.; Barbui, T.; Schmitz, O.
    • Review of Scientific Instruments, Vol. 87, Issue 11
    • DOI: 10.1063/1.4955286