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Title: Midplane neutral density profiles in the National Spherical Torus Experiment

Abstract

Atomic and molecular density data in the outer midplane of NSTX [Ono et al., Nucl. Fusion 40, 557 (2000)] are inferred from tangential camera data via a forward modeling procedure using the DEGAS 2 Monte Carlo neutral transport code. The observed Balmer-β light emission data from 17 shots during the 2010 NSTX campaign display no obvious trends with discharge parameters such as the divertor Balmer-α emission level or edge deuterium ion density. Simulations of 12 time slices in 7 of these discharges produce molecular densities near the vacuum vessel wall of 2–8 × 10{sup 17 }m{sup −3} and atomic densities ranging from 1 to 7 × 10{sup 16 }m{sup −3}; neither has a clear correlation with other parameters. Validation of the technique, begun in an earlier publication, is continued with an assessment of the sensitivity of the simulated camera image and neutral densities to uncertainties in the data input to the model. The simulated camera image is sensitive to the plasma profiles and virtually nothing else. The neutral densities at the vessel wall depend most strongly on the spatial distribution of the source; simulations with a localized neutral source yield densities within a factor of two of the baseline, uniform source, case. The uncertainties in themore » neutral densities associated with other model inputs and assumptions are ≤50%.« less

Authors:
; ; ; ; ;  [1];  [2]
  1. Princeton Plasma Physics Laboratory, Princeton University, P. O. Box 451, Princeton, New Jersey 08543-0451 (United States)
  2. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
Publication Date:
OSTI Identifier:
22490057
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 22; Journal Issue: 8; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BALMER LINES; CAMERAS; DEUTERIUM IONS; DIVERTORS; IMAGES; ION DENSITY; MONTE CARLO METHOD; NEUTRAL-PARTICLE TRANSPORT; NSTX DEVICE; PHOTON EMISSION; PLASMA RADIAL PROFILES; PLASMA SIMULATION; SENSITIVITY; SPATIAL DISTRIBUTION; VISIBLE RADIATION

Citation Formats

Stotler, D. P., E-mail: dstotler@pppl.gov, Bell, R. E., Diallo, A., LeBlanc, B. P., Podestà, M., Roquemore, A. L., Ross, P. W., and Scotti, F. Midplane neutral density profiles in the National Spherical Torus Experiment. United States: N. p., 2015. Web. doi:10.1063/1.4928372.
Stotler, D. P., E-mail: dstotler@pppl.gov, Bell, R. E., Diallo, A., LeBlanc, B. P., Podestà, M., Roquemore, A. L., Ross, P. W., & Scotti, F. Midplane neutral density profiles in the National Spherical Torus Experiment. United States. doi:10.1063/1.4928372.
Stotler, D. P., E-mail: dstotler@pppl.gov, Bell, R. E., Diallo, A., LeBlanc, B. P., Podestà, M., Roquemore, A. L., Ross, P. W., and Scotti, F. Sat . "Midplane neutral density profiles in the National Spherical Torus Experiment". United States. doi:10.1063/1.4928372.
@article{osti_22490057,
title = {Midplane neutral density profiles in the National Spherical Torus Experiment},
author = {Stotler, D. P., E-mail: dstotler@pppl.gov and Bell, R. E. and Diallo, A. and LeBlanc, B. P. and Podestà, M. and Roquemore, A. L. and Ross, P. W. and Scotti, F.},
abstractNote = {Atomic and molecular density data in the outer midplane of NSTX [Ono et al., Nucl. Fusion 40, 557 (2000)] are inferred from tangential camera data via a forward modeling procedure using the DEGAS 2 Monte Carlo neutral transport code. The observed Balmer-β light emission data from 17 shots during the 2010 NSTX campaign display no obvious trends with discharge parameters such as the divertor Balmer-α emission level or edge deuterium ion density. Simulations of 12 time slices in 7 of these discharges produce molecular densities near the vacuum vessel wall of 2–8 × 10{sup 17 }m{sup −3} and atomic densities ranging from 1 to 7 × 10{sup 16 }m{sup −3}; neither has a clear correlation with other parameters. Validation of the technique, begun in an earlier publication, is continued with an assessment of the sensitivity of the simulated camera image and neutral densities to uncertainties in the data input to the model. The simulated camera image is sensitive to the plasma profiles and virtually nothing else. The neutral densities at the vessel wall depend most strongly on the spatial distribution of the source; simulations with a localized neutral source yield densities within a factor of two of the baseline, uniform source, case. The uncertainties in the neutral densities associated with other model inputs and assumptions are ≤50%.},
doi = {10.1063/1.4928372},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 8,
volume = 22,
place = {United States},
year = {2015},
month = {8}
}

Works referenced in this record:

Midplane neutral density profiles in the National Spherical Torus Experiment
dataset, January 2015

  • Stotler, Daren; Scotti, F.; Bell, R.
  • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
  • DOI: 10.11578/1366462

Midplane neutral density profiles in the National Spherical Torus Experiment
dataset, January 2015

  • Stotler, Daren; Scotti, F.; Bell, R.
  • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
  • DOI: 10.11578/1366462

Midplane neutral density profiles in the National Spherical Torus Experiment
dataset, January 2015

  • Stotler, D.; Scotti, F.; Bell, R.
  • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
  • DOI: 10.11578/1562014

    Works referencing / citing this record:

    Midplane neutral density profiles in the National Spherical Torus Experiment
    dataset, January 2015

    • Stotler, Daren; Scotti, F.; Bell, R.
    • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
    • DOI: 10.11578/1366462

    Neutral Gas Transport Modeling with DEGAS 2
    journal, January 1994


    Ionization, recombination, and population of excited levels in hydrogen plasmas
    journal, April 1973

    • Johnson, L. C.; Hinnov, E.
    • Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 13, Issue 4
    • DOI: 10.1016/0022-4073(73)90064-2

    OSM-EIRENE modeling of neutral pressures in the Alcator C-Mod divertor
    journal, March 2005


    Progress towards the validation of models of the behavior of neutral helium in gas puff imaging experiments
    journal, June 2007


    Assessing material migration through 13C injection experiments
    journal, August 2011


    Implementation of a diffusion convection surface evolution model in WallDYN
    journal, July 2013


    Influence of neutral particles on scrape-off layer turbulence with application to the interpretation of fast camera data
    journal, July 2013


    Plasma facing surface composition during NSTX Li experiments
    journal, July 2013


    OEDGE modeling of outer wall erosion in NSTX and the effect of changes in neutral pressure
    journal, August 2015


    Reconstruction of NSTX midplane neutral density profiles from visible imaging data
    journal, August 2015


    Electron- and photon-impact atomic ionisation
    journal, November 2012


    Measurement of neutral density profile in TEXT using a diagnostic neutral beam
    journal, October 1990

    • Bengtson, Roger D.; Valanju, P. M.; Ouroua, A.
    • Review of Scientific Instruments, Vol. 61, Issue 10
    • DOI: 10.1063/1.1141697

    Inversion technique to obtain an emissivity profile from tangential line‐integrated hard x‐ray measurements
    journal, January 1995

    • Bell, Ronald E.
    • Review of Scientific Instruments, Vol. 66, Issue 1
    • DOI: 10.1063/1.1146350

    Improved elastic collision modeling in DEGAS 2 for low-temperature plasmas
    journal, December 2000

    • Kanzleiter, Randall J.; Stotler, Daren P.; Karney, Charles F. F.
    • Physics of Plasmas, Vol. 7, Issue 12
    • DOI: 10.1063/1.1321018

    Operation of the NSTX Thomson scattering system
    journal, March 2003

    • LeBlanc, B. P.; Bell, R. E.; Johnson, D. W.
    • Review of Scientific Instruments, Vol. 74, Issue 3
    • DOI: 10.1063/1.1532763

    Fast neutral pressure measurements in NSTX
    journal, March 2003

    • Raman, R.; Kugel, H. W.; Provost, T.
    • Review of Scientific Instruments, Vol. 74, Issue 3
    • DOI: 10.1063/1.1534896

    Physics of pedestal density profile formation and its impact on H-mode density limit in burning plasmas
    journal, October 2003

    • Mahdavi, M. A.; Maingi, R.; Groebner, R. J.
    • Physics of Plasmas, Vol. 10, Issue 10
    • DOI: 10.1063/1.1605101

    Scintillator based energetic ion loss diagnostic for the National Spherical Torus Experiment
    journal, January 2008

    • Darrow, D. S.
    • Review of Scientific Instruments, Vol. 79, Issue 2
    • DOI: 10.1063/1.2827514

    Saturation mechanisms for edge turbulence
    journal, December 2009

    • Russell, D. A.; Myra, J. R.; D’Ippolito, D. A.
    • Physics of Plasmas, Vol. 16, Issue 12
    • DOI: 10.1063/1.3270051

    Ratio of Balmer line intensities resulting from dissociative excitation of molecular hydrogen in an ionizing plasma
    journal, September 1989

    • Fujimoto, Takashi; Sawada, Keiji; Takahata, Kiyoto
    • Journal of Applied Physics, Vol. 66, Issue 6
    • DOI: 10.1063/1.344289

    Comparison of poloidal velocity measurements to neoclassical theory on the National Spherical Torus Experiment
    journal, August 2010

    • Bell, R. E.; Andre, R.; Kaye, S. M.
    • Physics of Plasmas, Vol. 17, Issue 8
    • DOI: 10.1063/1.3478571

    Effective ionization and dissociation rate coefficients of molecular hydrogen in plasma
    journal, September 1995

    • Sawada, Keiji; Fujimoto, Takashi
    • Journal of Applied Physics, Vol. 78, Issue 5
    • DOI: 10.1063/1.360037

    Invited Review Article: Gas puff imaging diagnostics of edge plasma turbulence in magnetic fusion devices
    journal, April 2017

    • Zweben, S. J.; Terry, J. L.; Stotler, D. P.
    • Review of Scientific Instruments, Vol. 88, Issue 4
    • DOI: 10.1063/1.4981873

    Kinetic theory of neutrals in a bounded plasma slab with inhomogeneous temperature and density profile
    journal, January 1982


    Modeling of neutral hydrogen velocities in the Tokamak Fusion Test Reactor
    journal, November 1996

    • Stotler, D. P.; Skinner, C. H.; Budny, R. V.
    • Physics of Plasmas, Vol. 3, Issue 11
    • DOI: 10.1063/1.871540

    Comments on particle and energy balance in the edge plasma of Alcator C-Mod
    journal, September 1998

    • Umansky, M. V.; Krasheninnikov, S. I.; LaBombard, B.
    • Physics of Plasmas, Vol. 5, Issue 9
    • DOI: 10.1063/1.873051

    Effects of neutral particles on edge dynamics in Alcator C-Mod plasmas
    journal, May 2000

    • Boivin, R. L.; Goetz, J. A.; Hubbard, A. E.
    • Physics of Plasmas, Vol. 7, Issue 5
    • DOI: 10.1063/1.874016

    Recombination in dense plasmas
    journal, October 1975


    Density limit of tokamaks
    journal, October 1983


    Reconstruction of current profile parameters and plasma shapes in tokamaks
    journal, November 1985


    Langmuir probe measurements in the limiter shadow of T-10: Non-linear scaling of edge density with central plasma density
    journal, December 1986


    Measurement of neutral density near the X point in the DIII-D tokamak
    journal, February 2000


    Equilibrium properties of spherical torus plasmas in NSTX
    journal, November 2001


    High-speed imaging of edge turbulence in NSTX
    journal, December 2003


    MHD-induced energetic ion loss during H-mode discharges in the National Spherical Torus Experiment
    journal, November 2004


    Observation of a high performance operating regime with small edge-localized modes in the National Spherical Torus Experiment
    journal, March 2005


    Core transport of lithium and carbon in ELM-free discharges with lithium wall conditioning in NSTX
    journal, July 2013


    Edge and SOL turbulence and blob variations over a large database in NSTX
    journal, September 2015


    A simple neutral density profile calculation for Tokamaks with   mfp <<a
    journal, November 1978


    The role of excited state ionization data on H and He generalized collisional–radiative coefficients
    journal, September 2009


    Plasma response to lithium-coated plasma-facing components in the National Spherical Torus Experiment
    journal, November 2009


    Interpretation of D α video diagnostics data as a contribution to plasma edge characterization
    journal, December 2010


    Effect of a deuterium gas puff on the edge plasma in NSTX
    journal, July 2014


    Neutral recycling effects on ITG turbulence
    journal, July 2017


    Scenario development during commissioning operations on the National Spherical Torus Experiment Upgrade
    journal, February 2018


    Midplane neutral density profiles in the National Spherical Torus Experiment
    dataset, January 2015

    • Stotler, D.; Scotti, F.; Bell, R.
    • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
    • DOI: 10.11578/1562014