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Title: Integrated Zeff analysis on the DIII-D Tokamak

Abstract

Determination of effective ion charge, or Zeff, from measurements of visible brems\-strahlung radiation made by multiple diagnostics is now integrated into a single analysis workflow within the plasma profile analysis module in OMFIT [Logan et al. Fus. Sci. Technol. 74 (2018) 125]. Measurements are made across the midplane of DIII-D with independent filterscope and spectrometer based diagnostics. Emission from 5215–5245 Å is measured by 16 filtered visible bremsstrahlung measurements (filterscopes) with a sampling rate of 20 kHz. The charge exchange recombination spectroscopy (CER) system utilizes scanning spectrometers, and typically measures emission near 5291 Å with approximately 20 active spatial views. Both Abel inversion and least squares minimization analyses are performed on these chordal measurements to infer the plasma emissivity profile with respect to magnetic flux coordinate ρ. Zeff is derived from this emissivity profile from a calculation involving electron density and temperature from the Thomson scattering diagnostic. This analysis has been applied for a range of plasma conditions including L-mode, H- mode and H-mode with impurity seeding. The Zeff inferred from VB data is shown to be in good agreement with the Zeff computed from CER impurity density profile measurements when C6+ is assumed to be the dominant impurity speciesmore » of the plasma. This new analysis is useful for cross checking diagnostics and measuring Zeff when all important impurities cannot be monitored directly with CER measurements.« less

Authors:
 [1];  [2];  [3];  [3];  [4]; ORCiD logo [5]
  1. University of California Irvine
  2. General Atomics
  3. Princeton Plasma Physics Laboratory (PPPL)
  4. University of California, Irvine
  5. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1570114
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Journal Volume: 14; Journal Issue: 10; Conference: 3rd European Conference of Plasma Diagnostics (EPCD 2019) - Lisbon, , Portugal - 5/6/2019 6:00:00 PM-5/9/2019 4:00:00 AM
Country of Publication:
United States
Language:
English

Citation Formats

Callahan, K. J., Chrystal, Colin, Grierson, B.A., Haskey, Shaun, Heidbrink, W. W., and Herfindal, Jeffrey L. Integrated Zeff analysis on the DIII-D Tokamak. United States: N. p., 2019. Web. doi:10.1088/1748-0221/14/10/C10002.
Callahan, K. J., Chrystal, Colin, Grierson, B.A., Haskey, Shaun, Heidbrink, W. W., & Herfindal, Jeffrey L. Integrated Zeff analysis on the DIII-D Tokamak. United States. doi:10.1088/1748-0221/14/10/C10002.
Callahan, K. J., Chrystal, Colin, Grierson, B.A., Haskey, Shaun, Heidbrink, W. W., and Herfindal, Jeffrey L. Tue . "Integrated Zeff analysis on the DIII-D Tokamak". United States. doi:10.1088/1748-0221/14/10/C10002. https://www.osti.gov/servlets/purl/1570114.
@article{osti_1570114,
title = {Integrated Zeff analysis on the DIII-D Tokamak},
author = {Callahan, K. J. and Chrystal, Colin and Grierson, B.A. and Haskey, Shaun and Heidbrink, W. W. and Herfindal, Jeffrey L.},
abstractNote = {Determination of effective ion charge, or Zeff, from measurements of visible brems\-strahlung radiation made by multiple diagnostics is now integrated into a single analysis workflow within the plasma profile analysis module in OMFIT [Logan et al. Fus. Sci. Technol. 74 (2018) 125]. Measurements are made across the midplane of DIII-D with independent filterscope and spectrometer based diagnostics. Emission from 5215–5245 Å is measured by 16 filtered visible bremsstrahlung measurements (filterscopes) with a sampling rate of 20 kHz. The charge exchange recombination spectroscopy (CER) system utilizes scanning spectrometers, and typically measures emission near 5291 Å with approximately 20 active spatial views. Both Abel inversion and least squares minimization analyses are performed on these chordal measurements to infer the plasma emissivity profile with respect to magnetic flux coordinate ρ. Zeff is derived from this emissivity profile from a calculation involving electron density and temperature from the Thomson scattering diagnostic. This analysis has been applied for a range of plasma conditions including L-mode, H- mode and H-mode with impurity seeding. The Zeff inferred from VB data is shown to be in good agreement with the Zeff computed from CER impurity density profile measurements when C6+ is assumed to be the dominant impurity species of the plasma. This new analysis is useful for cross checking diagnostics and measuring Zeff when all important impurities cannot be monitored directly with CER measurements.},
doi = {10.1088/1748-0221/14/10/C10002},
journal = {},
issn = {1748--0221},
number = 10,
volume = 14,
place = {United States},
year = {2019},
month = {10}
}

Conference:
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