Linear gyrokinetic simulations of microinstabilities within the pedestal region of H-mode NSTX discharges in a highly shaped geometry

M. Coury, W. Guttenfelder, D. R. Mikkelsen, J. M. Canik, G. P. Canal, A. Diallo, S. Kaye, G. J. Kramer, R. Maingi, NSTX-U team

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Linear (local) gyrokinetic predictions of edge microinstabilities in highly shaped, lithiated and non-lithiated NSTX discharges are reported using the gyrokinetic code GS2. Microtearing modes dominate the non-lithiated pedestal top. The stabilization of these modes at the lithiated pedestal top enables the electron temperature pedestal to extend further inwards, as observed experimentally. Kinetic ballooning modes are found to be unstable mainly at the mid-pedestal of both types of discharges, with unstable trapped electron modes nearer the separatrix region. At electron wavelengths, electron temperature gradient (ETG) modes are found to be unstable from mid-pedestal outwards for ηe, exp ∼2.2ηe, exp ∼2.2, with higher growth rates for the lithiated discharge. Near the separatrix, the critical temperature gradient for driving ETG modes is reduced in the presence of lithium, reflecting the reduction of the lithiated density gradients observed experimentally. A preliminary linear study in the edge of non-lithiated discharges shows that the equilibrium shaping alters the electrostatic modes stability, which was found more unstable at high plasma shaping.
LanguageEnglish
Article number062520
Number of pages9
JournalPhysics of Plasmas
Volume23
Issue number6
DOIs
Publication statusPublished - 30 Jun 2016

Fingerprint

geometry
temperature gradients
simulation
electron energy
ballooning modes
critical temperature
electrons
lithium
stabilization
electrostatics
gradients
kinetics
predictions
wavelengths

Keywords

  • linear (local) gyrokinetic predictions
  • microinstabilities
  • electron temperature gradient modes
  • high plasma shaping

Cite this

Coury, M., Guttenfelder, W., Mikkelsen, D. R., Canik, J. M., Canal, G. P., Diallo, A., ... team, NSTX-U. (2016). Linear gyrokinetic simulations of microinstabilities within the pedestal region of H-mode NSTX discharges in a highly shaped geometry. Physics of Plasmas, 23(6), [062520]. https://doi.org/10.1063/1.4954911
Coury, M. ; Guttenfelder, W. ; Mikkelsen, D. R. ; Canik, J. M. ; Canal, G. P. ; Diallo, A. ; Kaye, S. ; Kramer, G. J. ; Maingi, R. ; team, NSTX-U. / Linear gyrokinetic simulations of microinstabilities within the pedestal region of H-mode NSTX discharges in a highly shaped geometry. In: Physics of Plasmas. 2016 ; Vol. 23, No. 6.
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abstract = "Linear (local) gyrokinetic predictions of edge microinstabilities in highly shaped, lithiated and non-lithiated NSTX discharges are reported using the gyrokinetic code GS2. Microtearing modes dominate the non-lithiated pedestal top. The stabilization of these modes at the lithiated pedestal top enables the electron temperature pedestal to extend further inwards, as observed experimentally. Kinetic ballooning modes are found to be unstable mainly at the mid-pedestal of both types of discharges, with unstable trapped electron modes nearer the separatrix region. At electron wavelengths, electron temperature gradient (ETG) modes are found to be unstable from mid-pedestal outwards for ηe, exp ∼2.2ηe, exp ∼2.2, with higher growth rates for the lithiated discharge. Near the separatrix, the critical temperature gradient for driving ETG modes is reduced in the presence of lithium, reflecting the reduction of the lithiated density gradients observed experimentally. A preliminary linear study in the edge of non-lithiated discharges shows that the equilibrium shaping alters the electrostatic modes stability, which was found more unstable at high plasma shaping.",
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Coury, M, Guttenfelder, W, Mikkelsen, DR, Canik, JM, Canal, GP, Diallo, A, Kaye, S, Kramer, GJ, Maingi, R & team, NSTX-U 2016, 'Linear gyrokinetic simulations of microinstabilities within the pedestal region of H-mode NSTX discharges in a highly shaped geometry' Physics of Plasmas, vol. 23, no. 6, 062520. https://doi.org/10.1063/1.4954911

Linear gyrokinetic simulations of microinstabilities within the pedestal region of H-mode NSTX discharges in a highly shaped geometry. / Coury, M.; Guttenfelder, W.; Mikkelsen, D. R.; Canik, J. M.; Canal, G. P.; Diallo, A.; Kaye, S.; Kramer, G. J.; Maingi, R.; team, NSTX-U.

In: Physics of Plasmas, Vol. 23, No. 6, 062520, 30.06.2016.

Research output: Contribution to journalArticle

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T1 - Linear gyrokinetic simulations of microinstabilities within the pedestal region of H-mode NSTX discharges in a highly shaped geometry

AU - Coury, M.

AU - Guttenfelder, W.

AU - Mikkelsen, D. R.

AU - Canik, J. M.

AU - Canal, G. P.

AU - Diallo, A.

AU - Kaye, S.

AU - Kramer, G. J.

AU - Maingi, R.

AU - team, NSTX-U

N1 - © 2016 AIP Publishing LLC. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.

PY - 2016/6/30

Y1 - 2016/6/30

N2 - Linear (local) gyrokinetic predictions of edge microinstabilities in highly shaped, lithiated and non-lithiated NSTX discharges are reported using the gyrokinetic code GS2. Microtearing modes dominate the non-lithiated pedestal top. The stabilization of these modes at the lithiated pedestal top enables the electron temperature pedestal to extend further inwards, as observed experimentally. Kinetic ballooning modes are found to be unstable mainly at the mid-pedestal of both types of discharges, with unstable trapped electron modes nearer the separatrix region. At electron wavelengths, electron temperature gradient (ETG) modes are found to be unstable from mid-pedestal outwards for ηe, exp ∼2.2ηe, exp ∼2.2, with higher growth rates for the lithiated discharge. Near the separatrix, the critical temperature gradient for driving ETG modes is reduced in the presence of lithium, reflecting the reduction of the lithiated density gradients observed experimentally. A preliminary linear study in the edge of non-lithiated discharges shows that the equilibrium shaping alters the electrostatic modes stability, which was found more unstable at high plasma shaping.

AB - Linear (local) gyrokinetic predictions of edge microinstabilities in highly shaped, lithiated and non-lithiated NSTX discharges are reported using the gyrokinetic code GS2. Microtearing modes dominate the non-lithiated pedestal top. The stabilization of these modes at the lithiated pedestal top enables the electron temperature pedestal to extend further inwards, as observed experimentally. Kinetic ballooning modes are found to be unstable mainly at the mid-pedestal of both types of discharges, with unstable trapped electron modes nearer the separatrix region. At electron wavelengths, electron temperature gradient (ETG) modes are found to be unstable from mid-pedestal outwards for ηe, exp ∼2.2ηe, exp ∼2.2, with higher growth rates for the lithiated discharge. Near the separatrix, the critical temperature gradient for driving ETG modes is reduced in the presence of lithium, reflecting the reduction of the lithiated density gradients observed experimentally. A preliminary linear study in the edge of non-lithiated discharges shows that the equilibrium shaping alters the electrostatic modes stability, which was found more unstable at high plasma shaping.

KW - linear (local) gyrokinetic predictions

KW - microinstabilities

KW - electron temperature gradient modes

KW - high plasma shaping

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U2 - 10.1063/1.4954911

DO - 10.1063/1.4954911

M3 - Article

VL - 23

JO - Physics of Plasmas

T2 - Physics of Plasmas

JF - Physics of Plasmas

SN - 1070-664X

IS - 6

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ER -