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Title: A new stabilizing regime of tearing mode entrainment in the presence of a static error field

Abstract

Uncorrected static error fields in axisymmetric fusion devices are one of few remaining serious obstacles for advancing the present tokamak-based approach to practical reactors. The disruption due to magnetohydrodynamic tearing mode locking is one of them. Recently, a hypothesis has been proposed that there may exist a self-healing stabilized regime in which the static resonant error field is effectively shielded by forcing the mode slowly to rotate inductively by the applied non-axisymmetric field, that has been developed based on non-linear, resistive, reduced MHD simulation with cylindrical single helicity model. Proof-of-principle experiments in the DIII-D device showed that the magnetic mode structure on the plasma surface is qualitatively consistent with the simulation prediction. However, radial mode profiles revealed qualitatively different behavior. This finding led to a revised hypothesis that in actual non-circular toroidal devices, a tearing layer in forced rotation induces the shielding-out process at other rational surfaces when we take into account of multi-resonant Fourier components. The time evolution of the radial penetration was supportive of this hypothesis.

Authors:
 [1]; ORCiD logo [2]; ORCiD logo [1];  [3];  [4];  [4];  [1];  [5]; ORCiD logo [1];  [4];  [4]; ORCiD logo [4];  [6];  [7]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. National Inst. for Quantum and Radiological Science and Technology, Ibaraki (Japan)
  3. Oak Ridge Association Univ., Oak Ridge, TN (United States)
  4. General Atomics, San Diego, CA (United States)
  5. Columbia Univ., New York, NY (United States)
  6. Massachusetts Inst. of Technology, MA (United States). Lab. for Nuclear Science
  7. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
U.S. Dept. of Energy (USDOE), Washington D.C. (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1568810
Alternate Identifier(s):
OSTI ID: 1570111
Grant/Contract Number:  
FC02-04ER54698; AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 12; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
tearing mode locking; disruption; bifurcation

Citation Formats

Okabayashi, M., Inoue, S., Logan, N. C., Taylor, N. Z., Strait, E. J., de Grassie, J., Ferraro, N., Hanson, J., Jardin, S., La Haye, R. J., Liu, Y. Q., Paz-Soldan, C., Sugiyama, L., and Wingen, A. A new stabilizing regime of tearing mode entrainment in the presence of a static error field. United States: N. p., 2019. Web. doi:10.1088/1741-4326/ab37d2.
Okabayashi, M., Inoue, S., Logan, N. C., Taylor, N. Z., Strait, E. J., de Grassie, J., Ferraro, N., Hanson, J., Jardin, S., La Haye, R. J., Liu, Y. Q., Paz-Soldan, C., Sugiyama, L., & Wingen, A. A new stabilizing regime of tearing mode entrainment in the presence of a static error field. United States. doi:10.1088/1741-4326/ab37d2.
Okabayashi, M., Inoue, S., Logan, N. C., Taylor, N. Z., Strait, E. J., de Grassie, J., Ferraro, N., Hanson, J., Jardin, S., La Haye, R. J., Liu, Y. Q., Paz-Soldan, C., Sugiyama, L., and Wingen, A. Mon . "A new stabilizing regime of tearing mode entrainment in the presence of a static error field". United States. doi:10.1088/1741-4326/ab37d2.
@article{osti_1568810,
title = {A new stabilizing regime of tearing mode entrainment in the presence of a static error field},
author = {Okabayashi, M. and Inoue, S. and Logan, N. C. and Taylor, N. Z. and Strait, E. J. and de Grassie, J. and Ferraro, N. and Hanson, J. and Jardin, S. and La Haye, R. J. and Liu, Y. Q. and Paz-Soldan, C. and Sugiyama, L. and Wingen, A.},
abstractNote = {Uncorrected static error fields in axisymmetric fusion devices are one of few remaining serious obstacles for advancing the present tokamak-based approach to practical reactors. The disruption due to magnetohydrodynamic tearing mode locking is one of them. Recently, a hypothesis has been proposed that there may exist a self-healing stabilized regime in which the static resonant error field is effectively shielded by forcing the mode slowly to rotate inductively by the applied non-axisymmetric field, that has been developed based on non-linear, resistive, reduced MHD simulation with cylindrical single helicity model. Proof-of-principle experiments in the DIII-D device showed that the magnetic mode structure on the plasma surface is qualitatively consistent with the simulation prediction. However, radial mode profiles revealed qualitatively different behavior. This finding led to a revised hypothesis that in actual non-circular toroidal devices, a tearing layer in forced rotation induces the shielding-out process at other rational surfaces when we take into account of multi-resonant Fourier components. The time evolution of the radial penetration was supportive of this hypothesis.},
doi = {10.1088/1741-4326/ab37d2},
journal = {Nuclear Fusion},
number = 12,
volume = 59,
place = {United States},
year = {2019},
month = {9}
}

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This content will become publicly available on September 30, 2020
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