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Title: Electron Density Measurements in the National Spherical Torus Experiment Detached Divertor Region Using Stark Broadening of Deuterium Infrared Paschen Emission Lines

Abstract

Spatially resolved measurements of deuterium Balmer and Paschen line emission have been performed in the divertor region of the National Spherical Torus Experiment using a commercial 0.5 m Czerny-Turner spectrometer. While the Balmer emission lines, Balmer and Paschen continua in the ultraviolet and visible regions have been extensively used for tokamak divertor plasma temperature and density measurements, the diagnostic potential of infrared Paschen lines has been largely overlooked. We analyze Stark broadening of the lines corresponding to 2-n and 3-m transitions with principle quantum numbers n = 7-12 and m = 10-12 using recent Model Microfield Method calculations (C. Stehle and R. Hutcheon, Astron. Astrophys. Supl. Ser. 140, 93 (1999)). Densities in the range (5-50) x 10{sup 19} m{sup -3} are obtained in the recombining inner divertor plasma in 2-6 MW NBI H-mode discharges. The measured Paschen line profiles show good sensitivity to Stark effects, and low sensitivity to instrumental and Doppler broadening. The lines are situated in the near-infrared wavelength domain, where optical signal extraction schemes for harsh nuclear environments are practically realizable, and where a recombining divertor plasma is optically thin. These properties make them an attractive recombining divertor density diagnostic for a burning plasma experiment.

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
940885
Report Number(s):
UCRL-JRNL-230636
Journal ID: ISSN 0034-6748; RSINAK; TRN: US0807238
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Sci. Instrum., vol. 77, no. 10, October 18, 2006, pp. 10F127; Journal Volume: 77; Journal Issue: 10
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; ASTRON; DEUTERIUM; DIVERTORS; DOPPLER BROADENING; ELECTRON DENSITY; ELECTRON TEMPERATURE; ION TEMPERATURE; PASCHEN LINES; PLASMA; QUANTUM NUMBERS; SENSITIVITY; STARK EFFECT; WAVELENGTHS

Citation Formats

Soukhanovskii, V A, Johnson, D W, Kaita, R, and Roquemore, A L. Electron Density Measurements in the National Spherical Torus Experiment Detached Divertor Region Using Stark Broadening of Deuterium Infrared Paschen Emission Lines. United States: N. p., 2007. Web.
Soukhanovskii, V A, Johnson, D W, Kaita, R, & Roquemore, A L. Electron Density Measurements in the National Spherical Torus Experiment Detached Divertor Region Using Stark Broadening of Deuterium Infrared Paschen Emission Lines. United States.
Soukhanovskii, V A, Johnson, D W, Kaita, R, and Roquemore, A L. Fri . "Electron Density Measurements in the National Spherical Torus Experiment Detached Divertor Region Using Stark Broadening of Deuterium Infrared Paschen Emission Lines". United States. doi:. https://www.osti.gov/servlets/purl/940885.
@article{osti_940885,
title = {Electron Density Measurements in the National Spherical Torus Experiment Detached Divertor Region Using Stark Broadening of Deuterium Infrared Paschen Emission Lines},
author = {Soukhanovskii, V A and Johnson, D W and Kaita, R and Roquemore, A L},
abstractNote = {Spatially resolved measurements of deuterium Balmer and Paschen line emission have been performed in the divertor region of the National Spherical Torus Experiment using a commercial 0.5 m Czerny-Turner spectrometer. While the Balmer emission lines, Balmer and Paschen continua in the ultraviolet and visible regions have been extensively used for tokamak divertor plasma temperature and density measurements, the diagnostic potential of infrared Paschen lines has been largely overlooked. We analyze Stark broadening of the lines corresponding to 2-n and 3-m transitions with principle quantum numbers n = 7-12 and m = 10-12 using recent Model Microfield Method calculations (C. Stehle and R. Hutcheon, Astron. Astrophys. Supl. Ser. 140, 93 (1999)). Densities in the range (5-50) x 10{sup 19} m{sup -3} are obtained in the recombining inner divertor plasma in 2-6 MW NBI H-mode discharges. The measured Paschen line profiles show good sensitivity to Stark effects, and low sensitivity to instrumental and Doppler broadening. The lines are situated in the near-infrared wavelength domain, where optical signal extraction schemes for harsh nuclear environments are practically realizable, and where a recombining divertor plasma is optically thin. These properties make them an attractive recombining divertor density diagnostic for a burning plasma experiment.},
doi = {},
journal = {Review of Sci. Instrum., vol. 77, no. 10, October 18, 2006, pp. 10F127},
number = 10,
volume = 77,
place = {United States},
year = {Fri Apr 27 00:00:00 EDT 2007},
month = {Fri Apr 27 00:00:00 EDT 2007}
}