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Title: Equilibrium reconstruction with 3D eddy currents in the Lithium Tokamak eXperiment

Abstract

Axisymmetric free-boundary equilibrium reconstructions of tokamak plasmas in the Lithium Tokamak eXperiment (LTX) are performed using the PSI-Tri equilibrium code. Reconstructions in LTX are complicated by the presence of long-lived non-axisymmetric eddy currents generated by a vacuum vessel and first wall structures. To account for this effect, reconstructions are performed with additional toroidal current sources in these conducting regions. The eddy current sources are fixed in their poloidal distributions, but their magnitude is adjusted as part of the full reconstruction. Eddy distributions are computed by toroidally averaging currents, generated by coupling to vacuum field coils, from a simplified 3D filament model of important conducting structures. The full 3D eddy current fields are also used to enable the inclusion of local magnetic field measurements, which have strong 3D eddy current pick-up, as reconstruction constraints. Using this method, equilibrium reconstruction yields good agreement with all available diagnostic signals. Here, an accompanying field perturbation produced by 3D eddy currents on the plasma surface with a primarily n = 2, m = 1 character is also predicted for these equilibria.

Authors:
ORCiD logo [1]; ORCiD logo [2];  [3];  [2]
  1. Univ. of Washington, Seattle, WA (United States); Columbia Univ., New York, NY (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. Auburn Univ., AL (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of Washington, Seattle, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1358666
Alternate Identifier(s):
OSTI ID: 1361829; OSTI ID: 1608228
Grant/Contract Number:  
SC0016256; AC02-09CH11466
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 4; 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; 97 MATHEMATICS AND COMPUTING

Citation Formats

Hansen, C., Boyle, D. P., Schmitt, J. C., and Majeski, R. Equilibrium reconstruction with 3D eddy currents in the Lithium Tokamak eXperiment. United States: N. p., 2017. Web. doi:10.1063/1.4981214.
Hansen, C., Boyle, D. P., Schmitt, J. C., & Majeski, R. Equilibrium reconstruction with 3D eddy currents in the Lithium Tokamak eXperiment. United States. doi:10.1063/1.4981214.
Hansen, C., Boyle, D. P., Schmitt, J. C., and Majeski, R. Tue . "Equilibrium reconstruction with 3D eddy currents in the Lithium Tokamak eXperiment". United States. doi:10.1063/1.4981214. https://www.osti.gov/servlets/purl/1358666.
@article{osti_1358666,
title = {Equilibrium reconstruction with 3D eddy currents in the Lithium Tokamak eXperiment},
author = {Hansen, C. and Boyle, D. P. and Schmitt, J. C. and Majeski, R.},
abstractNote = {Axisymmetric free-boundary equilibrium reconstructions of tokamak plasmas in the Lithium Tokamak eXperiment (LTX) are performed using the PSI-Tri equilibrium code. Reconstructions in LTX are complicated by the presence of long-lived non-axisymmetric eddy currents generated by a vacuum vessel and first wall structures. To account for this effect, reconstructions are performed with additional toroidal current sources in these conducting regions. The eddy current sources are fixed in their poloidal distributions, but their magnitude is adjusted as part of the full reconstruction. Eddy distributions are computed by toroidally averaging currents, generated by coupling to vacuum field coils, from a simplified 3D filament model of important conducting structures. The full 3D eddy current fields are also used to enable the inclusion of local magnetic field measurements, which have strong 3D eddy current pick-up, as reconstruction constraints. Using this method, equilibrium reconstruction yields good agreement with all available diagnostic signals. Here, an accompanying field perturbation produced by 3D eddy currents on the plasma surface with a primarily n = 2, m = 1 character is also predicted for these equilibria.},
doi = {10.1063/1.4981214},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 4,
volume = 24,
place = {United States},
year = {2017},
month = {4}
}

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Cited by: 2 works
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    Works referencing / citing this record:

    Observation of Flat Electron Temperature Profiles in the Lithium Tokamak Experiment
    journal, July 2017