Nonlinear MHD simulations of QH-mode DIII-D plasmas and implications for ITER high Q scenarios

Feng Liu, G.T.A. Huijsmans, A. Loarte, A.M. Garofalo, W.M. Solomon, M. Hoelzl, B. Nkonga, S. Pamela, M. Becoulet, F. Orain, D. van Vugt

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Abstract

In nonlinear MHD simulations of DIII-D QH-mode plasmas it has been found that low n kink/peeling modes (KPMs) are unstable and grow to a saturated kink-peeling mode. The features of the dominant saturated KPMs, which are localised toroidally by nonlinear coupling of harmonics, such as mode frequencies, density fluctuations and their effect on pedestal particle and energy transport, are in good agreement with the observations of the edge harmonic oscillation typically present in DIII-D QH-mode experiments. The nonlinear evolution of MHD modes including both kink-peeling modes and ballooning modes, is investigated through MHD simulations by varying the pedestal current and pressure relative to the initial conditions of DIII-D QH-mode plasma. The edge current and pressure at the pedestal are key parameters for the plasma either saturating to a QH-mode regime or a ballooning mode dominant regime. The influence of E × B flow and its shear on the QH-mode plasma has been investigated. E × B flow shear has a strong stabilisation effect on the medium to high-n modes but is destabilising for the n = 2 mode. The QH-mode extrapolation results of an ITER Q = 10 plasma show that the pedestal currents are large enough to destabilise n = 1-5 KPMs, leading to a stationary saturated kink-peeling mode.

Original languageEnglish
Article number014039
JournalPlasma Physics and Controlled Fusion
Volume60
Issue number1
DOIs
Publication statusPublished - 1 Jan 2018

Fingerprint

Peeling
Magnetohydrodynamics
Q factors
Plasmas
peeling
simulation
Shear flow
Extrapolation
ballooning modes
Stabilization
harmonic oscillation
Experiments

Keywords

  • E × B rotation
  • EHO
  • JOREK
  • kink/peeling mode
  • nonlinear MHD simulation
  • QH-mode

Cite this

Liu, Feng ; Huijsmans, G.T.A. ; Loarte, A. ; Garofalo, A.M. ; Solomon, W.M. ; Hoelzl, M. ; Nkonga, B. ; Pamela, S. ; Becoulet, M. ; Orain, F. ; van Vugt, D. / Nonlinear MHD simulations of QH-mode DIII-D plasmas and implications for ITER high Q scenarios. In: Plasma Physics and Controlled Fusion. 2018 ; Vol. 60, No. 1.
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abstract = "In nonlinear MHD simulations of DIII-D QH-mode plasmas it has been found that low n kink/peeling modes (KPMs) are unstable and grow to a saturated kink-peeling mode. The features of the dominant saturated KPMs, which are localised toroidally by nonlinear coupling of harmonics, such as mode frequencies, density fluctuations and their effect on pedestal particle and energy transport, are in good agreement with the observations of the edge harmonic oscillation typically present in DIII-D QH-mode experiments. The nonlinear evolution of MHD modes including both kink-peeling modes and ballooning modes, is investigated through MHD simulations by varying the pedestal current and pressure relative to the initial conditions of DIII-D QH-mode plasma. The edge current and pressure at the pedestal are key parameters for the plasma either saturating to a QH-mode regime or a ballooning mode dominant regime. The influence of E × B flow and its shear on the QH-mode plasma has been investigated. E × B flow shear has a strong stabilisation effect on the medium to high-n modes but is destabilising for the n = 2 mode. The QH-mode extrapolation results of an ITER Q = 10 plasma show that the pedestal currents are large enough to destabilise n = 1-5 KPMs, leading to a stationary saturated kink-peeling mode.",
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author = "Feng Liu and G.T.A. Huijsmans and A. Loarte and A.M. Garofalo and W.M. Solomon and M. Hoelzl and B. Nkonga and S. Pamela and M. Becoulet and F. Orain and {van Vugt}, D.",
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Liu, F, Huijsmans, GTA, Loarte, A, Garofalo, AM, Solomon, WM, Hoelzl, M, Nkonga, B, Pamela, S, Becoulet, M, Orain, F & van Vugt, D 2018, 'Nonlinear MHD simulations of QH-mode DIII-D plasmas and implications for ITER high Q scenarios', Plasma Physics and Controlled Fusion, vol. 60, no. 1, 014039. https://doi.org/10.1088/1361-6587/aa934f

Nonlinear MHD simulations of QH-mode DIII-D plasmas and implications for ITER high Q scenarios. / Liu, Feng; Huijsmans, G.T.A.; Loarte, A.; Garofalo, A.M.; Solomon, W.M.; Hoelzl, M.; Nkonga, B.; Pamela, S.; Becoulet, M.; Orain, F.; van Vugt, D.

In: Plasma Physics and Controlled Fusion, Vol. 60, No. 1, 014039, 01.01.2018.

Research output: Contribution to journalArticleAcademicpeer-review

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T1 - Nonlinear MHD simulations of QH-mode DIII-D plasmas and implications for ITER high Q scenarios

AU - Liu, Feng

AU - Huijsmans, G.T.A.

AU - Loarte, A.

AU - Garofalo, A.M.

AU - Solomon, W.M.

AU - Hoelzl, M.

AU - Nkonga, B.

AU - Pamela, S.

AU - Becoulet, M.

AU - Orain, F.

AU - van Vugt, D.

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KW - E × B rotation

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