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Title: Reconstruction of NSTX midplane neutral density profiles from visible imaging data

Abstract

In this report the experimental determination of neutral densities in tokamak plasmas from line radiation is only accurate in the narrow region in which both the excitation rate and neutral density are significant. We describe an alternative procedure using the DEGAS 2 Monte Carlo neutral transport code to invert light emission data obtained from a tangentially viewing camera, yielding absolute radial profiles of deuterium atoms and molecules at midplane. That the neutral source in these simulations can be adequately characterized as a uniform flux at the vacuum vessel wall is demonstrated by the similarity of the shapes of the simulated and observed brightness profiles. A second test is obtained by comparing the resulting neutral pressures at the vessel walls with data from midplane micro-ion gauges. We also show that the simulated camera image is insensitive to variations in the spatial distribution of the neutral source.

Authors:
 [1];  [2];  [1];  [1];  [3]
+ Show Author Affiliations
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of Washington, Seattle, WA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1844492
Alternate Identifier(s):
OSTI ID: 1252240
Report Number(s):
LLNL-JRNL-742400
Journal ID: ISSN 0022-3115; 897169; TRN: US2302373
Grant/Contract Number:  
AC52-07NA27344; AC02-09CH11466; SC0006757
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 463; Journal Issue: N/A; Journal ID: ISSN 0022-3115
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; (PSI-21) NSTX DEGAS; natural edge modeling spectroscopy

Citation Formats

Stotler, D. P., Scotti, F., Bell, R. E., LeBlanc, B. P., and Raman, R. Reconstruction of NSTX midplane neutral density profiles from visible imaging data. United States: N. p., 2014. Web. doi:10.1016/j.jnucmat.2014.11.097.
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Stotler, D. P., Scotti, F., Bell, R. E., LeBlanc, B. P., & Raman, R. Reconstruction of NSTX midplane neutral density profiles from visible imaging data. United States. https://doi.org/10.1016/j.jnucmat.2014.11.097
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Stotler, D. P., Scotti, F., Bell, R. E., LeBlanc, B. P., and Raman, R. Wed . "Reconstruction of NSTX midplane neutral density profiles from visible imaging data". United States. https://doi.org/10.1016/j.jnucmat.2014.11.097. https://www.osti.gov/servlets/purl/1844492.
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@article{osti_1844492,
title = {Reconstruction of NSTX midplane neutral density profiles from visible imaging data},
author = {Stotler, D. P. and Scotti, F. and Bell, R. E. and LeBlanc, B. P. and Raman, R.},
abstractNote = {In this report the experimental determination of neutral densities in tokamak plasmas from line radiation is only accurate in the narrow region in which both the excitation rate and neutral density are significant. We describe an alternative procedure using the DEGAS 2 Monte Carlo neutral transport code to invert light emission data obtained from a tangentially viewing camera, yielding absolute radial profiles of deuterium atoms and molecules at midplane. That the neutral source in these simulations can be adequately characterized as a uniform flux at the vacuum vessel wall is demonstrated by the similarity of the shapes of the simulated and observed brightness profiles. A second test is obtained by comparing the resulting neutral pressures at the vessel walls with data from midplane micro-ion gauges. We also show that the simulated camera image is insensitive to variations in the spatial distribution of the neutral source.},
doi = {10.1016/j.jnucmat.2014.11.097},
journal = {Journal of Nuclear Materials},
number = N/A,
volume = 463,
place = {United States},
year = {Wed Dec 03 00:00:00 EST 2014},
month = {Wed Dec 03 00:00:00 EST 2014}
}
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https://doi.org/10.1016/j.jnucmat.2014.11.097
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    Works referencing / citing this record:

    Midplane neutral density profiles in the National Spherical Torus Experiment
    journal, August 2015

    • Stotler, D. P.; Scotti, F.; Bell, R. E.
    • Physics of Plasmas, Vol. 22, Issue 8
    • DOI: 10.1063/1.4928372
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