Isoparametric Bicubic Hermite Elements for Solution of the Grad-Shafranov Equation

Huysmans, G.; Goedbloed, J. P.; Kerner, W.

doi:10.1142/s0129183191000512

Cited by 184 publications

(218 citation statements)

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“…Besides CASTOR-K our suite of numerical codes comprises HELENA [13] to obtain magnetic equilibria, and the incompressible ideal-MHD code MISHKA [14] to compute the eigenmodes of a given equilibrium. The extensive identification of all the AEs of an equilibrium is key to the success of our methodical stability-analysis approach.…”

Section: Numerical Codes and Modelling Workflowmentioning

confidence: 99%

Comprehensive evaluation of the linear stability of Alfvén eigenmodes driven by alpha particles in an ITER baseline scenario

et al. 2016

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The linear stability of Alfvén eigenmodes in the presence of fusionborn alpha particles is thoroughly assessed for two variants of an ITER baseline scenario, which differ significantly in their core and pedestal temperatures. A systematic approach is used that considers all possible eigenmodes for a given magnetic equilibrium and determines their growth rates due to alpha-particle drive and Landau damping on fuel ions, helium ashes and electrons. This extensive stability study is efficiently conducted through the use of a specialized workflow that , which can rapidly evaluate the linear growth rate of an eigenmode. It is found that the fastest growing instabilities in the aforementioned ITER scenario are core-localized, low-shear toroidal Alfvén eigenmodes. The largest growth-rates occur in the scenario variant with higher core temperatures, which has the highest alpha-particle density and density gradient, for eigenmodes with toroidal mode numbers n ≈ 30. Although these eigenmodes suffer significant radiative damping, which is also evaluated, their growth rates remain larger than those of the most unstable eigenmodes found in the variant of the ITER baseline scenario with lower core temperatures, which have n ≈ 15 and are not affected by radiative damping.

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Section: Numerical Codes and Modelling Workflowmentioning

confidence: 99%

Comprehensive evaluation of the linear stability of Alfvén eigenmodes driven by alpha particles in an ITER baseline scenario

et al. 2016

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“…The reconstructed fixed-boundary equilibria are generated using the HELENA code [53], taking as input the current density profile from EFIT constrained by the motional Stark effect diagnostic and with a correction for the radial electric field. The pressure profile is taken from the Thomson scattering diagnostic, whilst the plasma boundary also comes from EFIT.…”

Section: Modelling the Effect Of Eccd In High Performance High Fast mentioning

confidence: 99%

Sawtooth control using electron cyclotron current drive in ITER demonstration plasmas in DIII-D

et al. 2012

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Sawtooth control using electron cyclotron current drive (ECCD) has been demonstrated in ITER-like plasmas with a large fast ion fraction, wide q = 1 radius and long uncontrolled sawtooth period in DIII-D. The sawtooth period is minimized when the ECCD resonance is just inside the q = 1 surface. Sawtooth destabilization using driven current inside q = 1 avoids the triggering of performance-degrading neoclassical tearing modes (NTMs), even at much higher pressure than required in the ITER baseline scenario. Operation at β N = 3 without 3/2 or 2/1 NTMs has been achieved in ITER demonstration plasmas when sawtooth control is applied using only modest ECCD power. Numerical modelling qualitatively confirms that the achieved driven current changes the local magnetic shear sufficiently to compensate for the stabilizing influence of the energetic particles in the plasma core.

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“…The equilibria are reconstructed by supplying the pressure and current profiles together with the plasma shape to the Helena code [30]. The current profile is found from the Transp code [31].…”

Section: Equilibria and Fast Ion Distribution Func-tions A Asdex mentioning

confidence: 99%

“…The equilibria are constrained by the position of the q = 1 surface inferred from the inversion radius found from the soft X-ray emission. The electron temperature and density profiles supplied to the Helena equilibrium code [30] are measured by using the Thomson scattering diagnostic. The current density profile is found using the Efit code [32].…”

Section: B Mastmentioning

confidence: 99%

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The effect of off-axis neutral beam injection on sawtooth stability in ASDEX Upgrade and Mega-Ampere Spherical Tokamak

Chapman

Bock

Pinches³

et al. 2009

Physics of Plasmas

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Sawtooth behaviour has been investigated in plasmas heated with off-axis neutral beam injection (NBI) in ASDEX Upgrade [A. Herrmann and O. Gruber, Fusion Sci. Technol. 44, 569 (2003)] and the Mega-Ampere Spherical Tokamak (MAST) [A Sykes et al., Nucl. Fusion 41, 1423(2001]. Provided that the fast ions are well confined, the sawtooth period is found to decrease as the neutral beam is injected further off-axis. Drift kinetic modelling of such discharges qualitatively shows that the passing fast ions born outside the q = 1 rational surface can destabilise the n = 1 internal kink mode, thought to be related to the sawtooth instability. This effect can be enhanced by optimising the deposition of the off-axis beam energetic particle population with respect to the mode location.

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Isoparametric Bicubic Hermite Elements for Solution of the Grad-Shafranov Equation

Cited by 184 publications

References 0 publications

Comprehensive evaluation of the linear stability of Alfvén eigenmodes driven by alpha particles in an ITER baseline scenario

Comprehensive evaluation of the linear stability of Alfvén eigenmodes driven by alpha particles in an ITER baseline scenario

Sawtooth control using electron cyclotron current drive in ITER demonstration plasmas in DIII-D

The effect of off-axis neutral beam injection on sawtooth stability in ASDEX Upgrade and Mega-Ampere Spherical Tokamak

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