Resistive wall mode control code maturity: progress and specific examples

Liu, Yueqiang; Chu, M. S.; Guo, Wenfeng; Villone, F.; Albanese, R.; Ambrosino, G.; Baruzzo, M.; Bolzonella, T.; Chapman, I. T.; Garofalo, A. M.; Gimblett, C. G.; Hastie, R. J.; Hender, T. C.; Jackson, G.L.; Haye, R.J. La; Lanctot, M.J.; In, Y.; Marchiori, G.; Okabayashi, M.; Paccagnella, R.; Palumbo, Maurizio Furno; Pironti, A.; Reimerdes, H.; Rubinacci, G.; Soppelsa, A.; Strait, E. J.; Ventre, Salvatore; Yadykin, D.

doi:10.1088/0741-3335/52/10/104002

Cited by 69 publications

(61 citation statements)

References 30 publications

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“…15 Calculations with the "MARS-K" code of the RWM stability of a DIII-D equilibrium indicate that beam ions can have a large effect on stability. 16 In NSTX, we find that energetic particles are generally stabilizing and that a reduction of this particle population leads to reduced RWM stability. A correlation between energetic particle modes and RWM destabilization has been observed in JT-60U.…”

Section: Introductionmentioning

confidence: 74%

“…However, it is possible that the kinetic effects of energetic particles could change somewhat. 16 Second, the RWM growth rate and real rotation frequency appear on both sides of the dispersion relation in Eq.…”

Section: A Perturbative Versus Self-consistent Approachesmentioning

confidence: 99%

“…Altogether, we believe that if the eigenfunction does not change much and w is not extraordinarily low, the differences between the perturbative and the self-consistent approaches should be minor. However, a comparison between the self-consistent and the perturbative approaches for a DIII-D equilibrium including energetic particles, with the MARS-K code, does show major differences between the approaches, 16 so the issue remains unresolved. The sensitivity of the code to input parameters does not seem to be able to fully explain the quantitative difference.…”

Section: Possible Further Changes To the Physical Modelmentioning

confidence: 99%

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The role of kinetic effects, including plasma rotation and energetic particles, in resistive wall mode stability

et al. 2010

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The resistive wall mode ͑RWM͒ instability in high-beta tokamaks is stabilized by energy dissipation mechanisms that depend on plasma rotation and kinetic effects. Kinetic modification of ideal stability calculated with the "MISK" code ͓B. Hu et al., Phys. Plasmas 12, 057301 ͑2005͔͒ is outlined. For an advanced scenario ITER ͓R. Aymar et al., Nucl. Fusion 41, 1301 ͑2001͔͒ plasma, the present calculation finds that alpha particles are required for RWM stability at presently expected levels of plasma rotation. Kinetic stabilization theory is tested in an experiment in the National Spherical Torus Experiment ͑NSTX͒ ͓M. Ono et al., Nucl. Fusion 40, 557 ͑2000͔͒ that produced marginally stable plasmas with various energetic particle contents. Plasmas with the highest and lowest energetic particle content agree with calculations predicting that increased energetic particle pressure is stabilizing but does not alter the nonmonotonic dependence of stability on plasma rotation due to thermal particle resonances. Presently, the full MISK model, including thermal particles and an isotropic slowing-down distribution function for energetic particles, overpredicts stability in NSTX experiments. Minor alteration of either effect in the theory may yield agreement; several possibilities are discussed.

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Section: Introductionmentioning

confidence: 74%

Section: A Perturbative Versus Self-consistent Approachesmentioning

confidence: 99%

Section: Possible Further Changes To the Physical Modelmentioning

confidence: 99%

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The role of kinetic effects, including plasma rotation and energetic particles, in resistive wall mode stability

et al. 2010

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“…The experimental results of DIII-D RWM onset condition have been analyzed with the MARS-K code, 38 using both perturbative and self-consistent approaches.…”

Section: Analysis With Mars-kmentioning

confidence: 99%

Off-axis fishbone-like instability and excitation of resistive wall modes in JT-60U and DIII-D

Okabayashi¹,

Matsunaga²,

deGrassie³

et al. 2011

Physics of Plasmas

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An energetic-particle (EP)-driven "off-axis-fishbone-like mode (OFM)" often triggers a resistive wall mode (RWM) in JT-60U and DIII-D devices, preventing long-duration high-b N discharges. In these experiments, the EPs are energetic ions (70-85 keV) injected by neutral beams to produce high-pressure plasmas. EP-driven bursting events reduce the EP density and the plasma rotation simultaneously. These changes are significant in high-b N low-rotation plasmas, where the RWM stability is predicted to be strongly influenced by the EP precession drift resonance and by the plasma rotation near the q ¼ 2 surface (kinetic effects). Analysis of these effects on stability with a self-consistent perturbation to the mode structure using the MARS-K code showed that the impact of EP losses and rotation drop is sufficient to destabilize the RWM in low-rotation plasmas, when the plasma rotation normalized by Alfvén frequency is only a few tenths of a percent near the q ¼ 2 surface. The OFM characteristics are very similar in JT-60U and DIII-D, including nonlinear mode evolution. The modes grow initially like a classical fishbone, and then the mode structure becomes strongly distorted. The dynamic response of the OFM to an applied n ¼ 1 external field indicates that the mode retains its external kink character. These comparative studies suggest that an energetic particle-driven "off-axis-fishbone-like mode" is a new EP-driven branch of the external kink mode in wall-stabilized plasmas, analogous to the relationship of the classical fishbone branch to the internal kink mode.

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“…Ref. 17 showed that a new instability with small growth rate can be excited when the trapped EPs were taken into account in the RWM dispersion relation. However, the effect of the trapped EPs on the RWM has not been fully resolved, and could be crucial for the future tokamak devices.…”

Section: Introductionmentioning

confidence: 99%

Stabilization of the resistive wall mode instability by trapped energetic particles

et al. 2011

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A theoretical model for investigating the effect of the trapped energetic particles ͑EPs͒ on the resistive wall mode ͑RWM͒ instability is proposed. The results demonstrate that the trapped EPs have a dramatic stabilizing effect on the RWM because of resonant interaction between the mode and the magnetic precession drift motion of the trapped EPs. The results also show that the effect of the trapped EPs depends on the wall position. In addition, the stabilizing effect becomes stronger when the plasma rotation is taken into account. For sufficiently fast plasma rotation, the trapped EPs can lead to the complete stabilization of the RWM. Furthermore, the trapped EPs can induce a finite real frequency of the RWM in the absence of plasma rotation.

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Resistive wall mode control code maturity: progress and specific examples

Cited by 69 publications

References 30 publications

The role of kinetic effects, including plasma rotation and energetic particles, in resistive wall mode stability

The role of kinetic effects, including plasma rotation and energetic particles, in resistive wall mode stability

Off-axis fishbone-like instability and excitation of resistive wall modes in JT-60U and DIII-D

Stabilization of the resistive wall mode instability by trapped energetic particles

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