Modelling of (2,1) NTM threshold in JET advanced scenarios

Maget, P.; Lütjens, H.; Coelho, R.; Alper, B.; Brix, M.; Buratti, P.; Buttery, R. J.; Luna, E. de la; Hawkes, N.; Huysmans, G.; Jenkins, I.; Challis, C.; Giroud, C.; Litaudon, X.; Mailloux, J.; Ottaviani, M.; Contributors, Jet‐Efda

doi:10.1088/0029-5515/50/4/045004

Cited by 21 publications

(24 citation statements)

References 56 publications

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“…It can be observed that with the step adjustment rules in Section 4, the behavior of the Newton-Krylov solver is close to its optimum in both the linear and the nonlinear part of the dynamics. An extensive use of the code for production purposes also supports this observation [30].…”

Section: Application To An Ideal Internal Kinksupporting

confidence: 58%

XTOR-2F: A fully implicit Newton–Krylov solver applied to nonlinear 3D extended MHD in tokamaks

Lütjens

Luciani

2010

Journal of Computational Physics

125

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Section: Application To An Ideal Internal Kinksupporting

confidence: 58%

XTOR-2F: A fully implicit Newton–Krylov solver applied to nonlinear 3D extended MHD in tokamaks

Lütjens

Luciani

2010

Journal of Computational Physics

125

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“…proxies of the ratio of the thermal kinetic to magnetic pressure There is also an apparent correlation of [8,[13][14][15]. Because this limit is a resistive mode rather than an ideal mode, the result is often a dramatic loss of energy confinement rather than an immediate disruption.…”

Section: Existence Domainsmentioning

confidence: 99%

Development of advanced inductive scenarios for ITER

et al. 2013

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Regression analysis on the multi-tokamak database has been performed, but it appears that the database is not conditioned sufficiently well to yield a new scaling for this type of plasma.Coordinated experiments on size scaling using the dimensionless parameter scaling approach find a weaker scaling with normalized gyroradius than the standard H-mode scaling. Preliminary studies on scaling with collision frequency show a favorable scaling stronger than the standard H-mode scaling. Coordinated modeling activity has resulted in successful benchmarking of modeling codes in the ITER regime. Validation of transport models using these codes on present-day expeirments is in progress, but no single model has been shown to capture the variations seen in the experiments. However, projection to ITER using these models is in general agreement with the favorable projections found with the empirical scalings.

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“…For a q ¼ m=n island of full width w at rational surface q of poloidal mode m and toroidal mode n, the island growth or decay 4,6,20,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] is here given by the MRE,…”

Section: Form Of the Modified Rutherford Equation Used For Empirimentioning

confidence: 99%

Aspect ratio effects on neoclassical tearing modes from comparison between DIII-D and National Spherical Torus Experiment

et al. 2012

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Neoclassical tearing mode islands are sustained by helically perturbed bootstrap currents arising at finite beta from toroidal effects that trap a fraction of the particles in non-circulating orbits. DIII-D and NSTX are here operated with similar shape and cross-sectional area but almost a factor of two difference in inverse aspect ratio a=R. In these experiments, destabilized n ¼ 1 tearing modes were self-stabilized (reached the "marginal point") by reducing neutral-beam power and thus beta. The measure of the marginal island gives information on the small-island stabilizing physics that in part (with seeding) governs onset. The marginal island width on NSTX is found to be about three times the ion banana width and agrees with that measured in DIII-D, except for DIII-D modes closer to the magnetic axis, which are about two times the ion banana width. There is a balance of the helically perturbed bootstrap term with small island effects with the sum of the classical and curvature terms in the modified Rutherford equation for tearing-mode stability at the experimental marginal point. Empirical evaluation of this sum indicates that while the stabilizing effect of the curvature term is negligible in DIII-D, it is important in NSTX. The mode temporal behavior from the start of neutral-beam injection reduction also suggests that NSTX operates closer to marginal classical tearing stability; this explains why there is little hysteresis in beta between mode onset, saturation, and self-stabilization (while DIII-D has large hysteresis in beta). NIMROD code module component calculations based on DIII-D and NSTX reconstructed experimental equilibria are used to diagnose and confirm the relative importance of the stabilizing curvature effect, an advantage for low aspect ratio; the relatively greater curvature effect makes for less susceptibility to NTM onset even if the classical tearing stability index is near marginal. V C 2012 American Institute of Physics. [http://dx.

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Modelling of (2,1) NTM threshold in JET advanced scenarios

Cited by 21 publications

References 56 publications

XTOR-2F: A fully implicit Newton–Krylov solver applied to nonlinear 3D extended MHD in tokamaks

XTOR-2F: A fully implicit Newton–Krylov solver applied to nonlinear 3D extended MHD in tokamaks

Development of advanced inductive scenarios for ITER

Aspect ratio effects on neoclassical tearing modes from comparison between DIII-D and National Spherical Torus Experiment

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