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Title: Spatial and temporal analysis of DIII-D 3D magnetic diagnostic data

Abstract

An extensive set of magnetic diagnostics in DIII-D is aimed at measuring non-axisymmetric "3D" features of tokamak plasmas, with typical amplitudes ~10 -3 to 10 -5 of the total magnetic field. We describe hardware and software techniques used at DIII-D to condition the individual signals and analysis to estimate the spatial structure from an ensemble of discrete measurements. Lastly, applications of the analysis include detection of non-rotating MHD instabilities, plasma control, and validation of MHD stability and 3D equilibrium models.

Authors:
 [1];  [2];  [3];  [4]
  1. General Atomics, San Diego, CA (United States)
  2. General Atomics, San Diego, CA (United States); U.S. Dept. of Energy, Germantown, MD (United States)
  3. Columbia Univ., New York, NY (United States)
  4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1309459
Grant/Contract Number:
AC02-09CH11466; FG02-04ER54761; FC02-04ER54698
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 87; Journal Issue: 11; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Strait, E. J., King, J. D., Hanson, J. M., and Logan, N. C. Spatial and temporal analysis of DIII-D 3D magnetic diagnostic data. United States: N. p., 2016. Web. doi:10.1063/1.4960419.
Strait, E. J., King, J. D., Hanson, J. M., & Logan, N. C. Spatial and temporal analysis of DIII-D 3D magnetic diagnostic data. United States. doi:10.1063/1.4960419.
Strait, E. J., King, J. D., Hanson, J. M., and Logan, N. C. 2016. "Spatial and temporal analysis of DIII-D 3D magnetic diagnostic data". United States. doi:10.1063/1.4960419. https://www.osti.gov/servlets/purl/1309459.
@article{osti_1309459,
title = {Spatial and temporal analysis of DIII-D 3D magnetic diagnostic data},
author = {Strait, E. J. and King, J. D. and Hanson, J. M. and Logan, N. C.},
abstractNote = {An extensive set of magnetic diagnostics in DIII-D is aimed at measuring non-axisymmetric "3D" features of tokamak plasmas, with typical amplitudes ~10-3 to 10-5 of the total magnetic field. We describe hardware and software techniques used at DIII-D to condition the individual signals and analysis to estimate the spatial structure from an ensemble of discrete measurements. Lastly, applications of the analysis include detection of non-rotating MHD instabilities, plasma control, and validation of MHD stability and 3D equilibrium models.},
doi = {10.1063/1.4960419},
journal = {Review of Scientific Instruments},
number = 11,
volume = 87,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
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  • In an extensive set of magnetic diagnostics in DIII-D we aimed at measuring non-axisymmetric “3D” features of tokamak plasmas, with typical amplitudes ~10 -3 to 10 -5 of the total magnetic field. Here, we describe hardware and software techniques used at DIII-D to condition the individual signals, and analysis to estimate the spatial structure from an ensemble of discrete measurements. Furthermore, applications of the analysis include detection of nonrotating MHD instabilities, plasma control, and validation of MHD stability and 3D equilibrium models
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  • In DIII-D, visible spectroscopic measurements of the He II 468.6 nm and C VI 529.2 nm Doppler broadened spectral lines, resulting from charge exchange recombination interactions between beam neutral atoms and plasma ions, are performed to determine ion temperatures, and toroidal and poloidal rotation velocities. The diagnostics system comprises 32 viewing chords spanning a typical minor radius of 63 cm across the midplane, of which 16 spatial chords span 11 cm of the plasma edge just within the separatrix. A temporal resolution of 260 {mu}s per time slice can be obtained as a result of using MCP phosphors with shortmore » decay times and fast camera readout electronics. Results from this system will be used in radial electric field comparisons with theory at the L--H transition and ion transport analysis.« less
  • The temporal and spatial (partial volume) response characteristics of ionization chambers used for measuring radiation exposures in x-ray quality control (QC) programs were evaluated. Five ionization chambers were evaluated using a pencil beam scanning x-ray source and a conventional radiographic system. The spatial response was determined by recording the exposure during scanning of the pencil beam or in increments using a slitted lead sheet on a conventional x-ray system. The temporal response was determined by recording x-ray wave forms using the different ionization chambers. The effects of partial volume irradiation of the chambers makes them unsuitable for use under thesemore » conditions, except for those designed for exposure measurements in computed tomography. The temporal response of many chambers resembles that of a typical resistive-capacitive circuit, making them unsuitable for exposure time measurements or x-ray wave for evaluation. The appropriate ionization chamber must be selected for exposure measurements and quality control in diagnostic radiology. 4 refs., 8 figs., 2 tabs.« less