Search Menu
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information
Search Scholarly Publications

Title: Determination of current and rotational transform profiles in a current-carrying stellarator using soft x-ray emissivity measurements

Abstract

In this research, collimated soft X-ray (SXR) emissivity measurements from multi-channel cameras on the Compact Toroidal Hybrid (CTH) tokamak/torsatron device are incorporated in the 3D equilibrium reconstruction code V3FIT to reconstruct the shape of flux surfaces and infer the current distribution within the plasma. Equilibrium reconstructions of sawtoothing plasmas that use data from both SXR and external magnetic diagnostics show the central safety factor to be near unity under the assumption that SXR iso-emissivity contours lie on magnetic flux surfaces. The reconstruction results are consistent with those using the external magnetic data and a constraint on the location of q = 1 surfaces determined from the sawtooth inversion surface extracted from SXR brightness profiles. The agreement justifies the use of approximating SXR emission as a flux function in CTH, at least within the core of the plasma, subject to the spatial resolution of the SXR diagnostics. Lastly, this improved reconstruction of the central current density indicates that the current profile peakedness decreases with increasing external transform and that the internal inductance is not a relevant measure of how peaked the current profile is in hybrid discharges.

Authors:
ORCiD logo [1]; ORCiD logo [2];  [1];  [1]; ORCiD logo [1]; ORCiD logo [3];  [1];  [1]; ORCiD logo [1];  [1]
+ Show Author Affiliations
  1. Auburn Univ., AL (United States). Physics Department
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Auburn Univ., AL (United States). Physics Department ; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1422574
Alternate Identifier(s):
OSTI ID: 1418890
Grant/Contract Number:  
AC05-00OR22725; FG02-00ER54610
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 1; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY

Citation Formats

Ma, X., Cianciosa, M. R., Ennis, D. A., Hanson, J. D., Hartwell, G. J., Herfindal, J. L., Howell, E. C., Knowlton, S. F., Maurer, D. A., and Traverso, P. J. Determination of current and rotational transform profiles in a current-carrying stellarator using soft x-ray emissivity measurements. United States: N. p., 2018. Web. doi:10.1063/1.5013347.
Copy to clipboard
Ma, X., Cianciosa, M. R., Ennis, D. A., Hanson, J. D., Hartwell, G. J., Herfindal, J. L., Howell, E. C., Knowlton, S. F., Maurer, D. A., & Traverso, P. J. Determination of current and rotational transform profiles in a current-carrying stellarator using soft x-ray emissivity measurements. United States. https://doi.org/10.1063/1.5013347
Copy to clipboard
Ma, X., Cianciosa, M. R., Ennis, D. A., Hanson, J. D., Hartwell, G. J., Herfindal, J. L., Howell, E. C., Knowlton, S. F., Maurer, D. A., and Traverso, P. J. Wed . "Determination of current and rotational transform profiles in a current-carrying stellarator using soft x-ray emissivity measurements". United States. https://doi.org/10.1063/1.5013347. https://www.osti.gov/servlets/purl/1422574.
Copy to clipboard
@article{osti_1422574,
title = {Determination of current and rotational transform profiles in a current-carrying stellarator using soft x-ray emissivity measurements},
author = {Ma, X. and Cianciosa, M. R. and Ennis, D. A. and Hanson, J. D. and Hartwell, G. J. and Herfindal, J. L. and Howell, E. C. and Knowlton, S. F. and Maurer, D. A. and Traverso, P. J.},
abstractNote = {In this research, collimated soft X-ray (SXR) emissivity measurements from multi-channel cameras on the Compact Toroidal Hybrid (CTH) tokamak/torsatron device are incorporated in the 3D equilibrium reconstruction code V3FIT to reconstruct the shape of flux surfaces and infer the current distribution within the plasma. Equilibrium reconstructions of sawtoothing plasmas that use data from both SXR and external magnetic diagnostics show the central safety factor to be near unity under the assumption that SXR iso-emissivity contours lie on magnetic flux surfaces. The reconstruction results are consistent with those using the external magnetic data and a constraint on the location of q = 1 surfaces determined from the sawtooth inversion surface extracted from SXR brightness profiles. The agreement justifies the use of approximating SXR emission as a flux function in CTH, at least within the core of the plasma, subject to the spatial resolution of the SXR diagnostics. Lastly, this improved reconstruction of the central current density indicates that the current profile peakedness decreases with increasing external transform and that the internal inductance is not a relevant measure of how peaked the current profile is in hybrid discharges.},
doi = {10.1063/1.5013347},
journal = {Physics of Plasmas},
number = 1,
volume = 25,
place = {United States},
year = {2018},
month = {1}
}
Copy to clipboard
Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1063/1.5013347
Copyright Statement
Other availability
Search WorldCat Search WorldCat to find libraries that may hold this journal
Citation Metrics:
Cited by: 1 work
Citation information provided by
Web of Science

Figures / Tables:

FIG. 1 FIG. 1: Rendering of the last closed flux surface of a CTH plasma. Poloidal slices (highlighted in grey) indicate the toroidal locations of SXR cameras used for 3D equilibrium reconstructions.
All figures and tables (8 total)
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

Works referenced in this record:

Non-axisymmetric equilibrium reconstruction of a current-carrying stellarator using external magnetic and soft x-ray inversion radius measurements
journal, December 2015

  • Ma, X.; Maurer, D. A.; Knowlton, S. F.
  • Physics of Plasmas, Vol. 22, Issue 12
  • DOI: 10.1063/1.4938031

Design and initial operation of a two-color soft x-ray camera system on the Compact Toroidal Hybrid experiment
journal, November 2014

  • Herfindal, J. L.; Dawson, J. D.; Ennis, D. A.
  • Review of Scientific Instruments, Vol. 85, Issue 11
  • DOI: 10.1063/1.4892540

Separation of β̄ p and ℓ i in tokamaks of non-circular cross-section
journal, October 1985

First measurement of poloidal-field-induced Faraday rotation in a tokamak plasma
journal, December 1978

Tangential soft x-ray imaging for shape and current profile measurements
journal, March 2003

  • Tritz, K.; Fonck, R.; Reinke, M.
  • Review of Scientific Instruments, Vol. 74, Issue 3
  • DOI: 10.1063/1.1537876

Determination of current distribution in a tokamak
journal, January 1982

Why beta p and l i cannot be separately measured in a near circular tokamak
journal, November 1993

Equilibrium reconstruction of plasma profiles based on soft x-ray imaging in DIII-D
journal, December 2008

The interpretation of tokamak magnetic diagnostics
journal, July 1991

Magnetic analysis of non-circular cross-section tokamaks
journal, June 1982

Determination of current distribution in JET from soft X-ray measurements
journal, May 1989

Studies of Internal Disruptions and m = 1 Oscillations in Tokamak Discharges with Soft—X-Ray Tecniques
journal, November 1974

Discrepancies between soft x-ray emissivity contours and magnetic flux surfaces in Alcator C-Mod
journal, March 1996

Tomographic imaging of MHD activity in tokamaks by combining diode arrays and a tangentially viewing pinhole camera
journal, August 1988

  • Holland, A.; Fonck, R. J.; Powell, E. T.
  • Review of Scientific Instruments, Vol. 59, Issue 8
  • DOI: 10.1063/1.1140070

Three-dimensional free boundary calculations using a spectral Green's function method
journal, December 1986

The multichannel motional Stark effect diagnostic on TFTR
journal, October 1992

  • Levinton, F. M.
  • Review of Scientific Instruments, Vol. 63, Issue 10
  • DOI: 10.1063/1.1143466

Current distribution modification measurements in the PBX-M tokamak
journal, October 1993

Design, Construction, and Operation of the Compact Toroidal Hybrid
journal, May 2017

MOMCON: A spectral code for obtaining three-dimensional magnetohydrodynamic equilibria
journal, February 1986

Current distribution measurement in a tokamak by FIR polarimetry (invited)
journal, August 1986

  • Soltwisch, H.
  • Review of Scientific Instruments, Vol. 57, Issue 8
  • DOI: 10.1063/1.1138803

V3FIT: a code for three-dimensional equilibrium reconstruction
journal, July 2009

Application of x-ray imaging to current profile measurements in the PEGASUS experiment
journal, January 1999

  • Tritz, K.; Fonck, R.; Thorson, T.
  • Review of Scientific Instruments, Vol. 70, Issue 1
  • DOI: 10.1063/1.1149273

Current profile measurements with motional Stark effect polarimeter in the JT-60U tokamak
journal, March 1997

    Sort by:
    [ × clear filter / sort ]

    Works referencing / citing this record:

    Development of a non-parametric Gaussian process model in the three-dimensional equilibrium reconstruction code V3FIT
    journal, January 2020

    Sawtooth oscillation behavior with varying amounts of applied stellarator rotational transform
    journal, March 2019

    • Herfindal, J. L.; Maurer, D. A.; Hartwell, G. J.
    • Physics of Plasmas, Vol. 26, Issue 3
    • DOI: 10.1063/1.5080242
      Sort by:
      [ × clear filter / sort ]

      Figures / Tables found in this record:

      FIG. 1 (p. 2)figure
      FIG. 2 (p. 3)figure
      FIG. 3 (p. 4)figure
      FIG. 4 (p. 5)figure
      FIG. 5 (p. 5)figure
      FIG. 6 (p. 6)figure
      FIG. 7 (p. 7)figure
      FIG. 8 (p. 8)figure
        [ × clear filter / sort ]
        Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.

        Similar Records in DOE PAGES and OSTI.GOV collections: