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Title: Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak [Imaging divertor strike point splitting in RMP ELM suppression experiments]

Abstract

Fast visible imaging of the lower divertor from above is used to study the structure and dynamics of lobes induced by resonant magnetic perturbations (RMPs) in Edge-Localized Mode (ELM) suppression experiments in DIII-D. The best compromise between the amount of light and sharp imaging was obtained using emission at 601 nm from Fulcher band molecular deuterium. Multiple spatially resolved peaks in the D 2 emission, taken as a proxy for the particle flux, are readily resolved during RMPs, in contrast to the heat flux measured by infrared cameras, which shows little spatial structure in ITER-like conditions. The 25 mm objective lens provides high spatial resolution (2–4 mm/pixel) from the centerpost to the outer shelf over 40° toroidally that overlaps the field of view of the IRTV that measures the divertor heat flux, allowing direct comparison in non-axisymmetric discharges. The image is coupled to a Phantom 7.3 camera using a Schott wound fiber bundle, providing high temporal resolution that allows the lobe dynamics to be resolved between ELMs and across ELM suppression onset. Furthermore, these measurements are used to study the heat and particle flux in 3D magnetic fields and to validate models for the plasma response to RMPs.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2];  [3];  [4];  [5];  [5];  [5];  [6];  [7];  [2]
  1. Univ. of California San Diego, La Jolla, CA (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of California, Los Angeles, Los Angeles, CA (United States)
  4. Oregon State Univ., Corvallis, OR (United States)
  5. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  6. Oak Ridge Associated Univ., Oak Ridge, TN (United States)
  7. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1542708
Alternate Identifier(s):
OSTI ID: 1466875
Report Number(s):
LLNL-JRNL-777842
Journal ID: ISSN 0034-6748; 963969
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 89; Journal Issue: 10; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Moyer, R. A., Bykov, I., Orlov, D. M., Evans, T. E., Lee, J. S., Teklu, A. M., Fenstermacher, M. E., Makowski, M., Lasnier, C. J., Wang, H. Q., Watkins, J. G., and Wu, W. Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak [Imaging divertor strike point splitting in RMP ELM suppression experiments]. United States: N. p., 2018. Web. doi:10.1063/1.5038350.
Moyer, R. A., Bykov, I., Orlov, D. M., Evans, T. E., Lee, J. S., Teklu, A. M., Fenstermacher, M. E., Makowski, M., Lasnier, C. J., Wang, H. Q., Watkins, J. G., & Wu, W. Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak [Imaging divertor strike point splitting in RMP ELM suppression experiments]. United States. doi:10.1063/1.5038350.
Moyer, R. A., Bykov, I., Orlov, D. M., Evans, T. E., Lee, J. S., Teklu, A. M., Fenstermacher, M. E., Makowski, M., Lasnier, C. J., Wang, H. Q., Watkins, J. G., and Wu, W. Mon . "Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak [Imaging divertor strike point splitting in RMP ELM suppression experiments]". United States. doi:10.1063/1.5038350. https://www.osti.gov/servlets/purl/1542708.
@article{osti_1542708,
title = {Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak [Imaging divertor strike point splitting in RMP ELM suppression experiments]},
author = {Moyer, R. A. and Bykov, I. and Orlov, D. M. and Evans, T. E. and Lee, J. S. and Teklu, A. M. and Fenstermacher, M. E. and Makowski, M. and Lasnier, C. J. and Wang, H. Q. and Watkins, J. G. and Wu, W.},
abstractNote = {Fast visible imaging of the lower divertor from above is used to study the structure and dynamics of lobes induced by resonant magnetic perturbations (RMPs) in Edge-Localized Mode (ELM) suppression experiments in DIII-D. The best compromise between the amount of light and sharp imaging was obtained using emission at 601 nm from Fulcher band molecular deuterium. Multiple spatially resolved peaks in the D2 emission, taken as a proxy for the particle flux, are readily resolved during RMPs, in contrast to the heat flux measured by infrared cameras, which shows little spatial structure in ITER-like conditions. The 25 mm objective lens provides high spatial resolution (2–4 mm/pixel) from the centerpost to the outer shelf over 40° toroidally that overlaps the field of view of the IRTV that measures the divertor heat flux, allowing direct comparison in non-axisymmetric discharges. The image is coupled to a Phantom 7.3 camera using a Schott wound fiber bundle, providing high temporal resolution that allows the lobe dynamics to be resolved between ELMs and across ELM suppression onset. Furthermore, these measurements are used to study the heat and particle flux in 3D magnetic fields and to validate models for the plasma response to RMPs.},
doi = {10.1063/1.5038350},
journal = {Review of Scientific Instruments},
number = 10,
volume = 89,
place = {United States},
year = {2018},
month = {8}
}

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Figures / Tables:

FIG. 1 FIG. 1: DIII-D fast camera and shield box enclosure: (1) Phantom CMOS camera; (2) camera power supply; (3) communications link; (4) duel 2 inch filter wheels; (5) neutron shielding; (6) γ-ray and magnetic shielding; (7) coherent fiber bundle; (8) and (9) relay optics.

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Works referenced in this record:

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