PB3D: A new code for edge 3-D ideal linear peeling-ballooning stability

Weyens, T.; Sánchez, Raúl; Huijsmans, Gta Guido; Loarte, A.; Garcia, L.

doi:10.1016/j.jcp.2016.10.054

Cited by 6 publications

(4 citation statements)

References 21 publications

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“…The observation of 'medium' toroidal mode numbers n BM motivates finite-n ideal MHD stability calculations in 3D geometry [95,96]. One should keep in mind that the phase delay method is used to determine n BM .…”

Section: Discussion About Edge Stability In 3d Tokamak Geometrymentioning

confidence: 99%

Dynamics of ideal modes and subsequent ELM crashes in 3D tokamak geometry from external magnetic perturbations

Willensdorfer

Cote

Griener

et al. 2018

Plasma Phys. Control. Fusion

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The impact of three-dimensional (3D) tokamak geometry from external magnetic perturbations on edge instabilities has been examined in high confinement mode plasmas with edge localised modes (ELMs) in ASDEX Upgrade. The 3D geometry has been probed using rigidly rotating MP fields. The measured distortions of the plasma boundary are compared to single-fluid ideal magnetohydrodynamic (MHD) equilibria using VMEC and MARS-F applying ideal and resistive MHD, whereas VMEC uses only ideal MHD. Both codes accurately reproduce the measured radial displacements of the edge density and temperature profiles in amplitude, toroidal phase and their dependence on the applied poloidal mode spectrum.The induced 3D geometry distorts the local magnetic shear, which locally reduces the stabilising effect from field-line bending at certain most unstable field lines. Around these field lines, we observe additional stable ideal MHD modes with clear ballooning structure in-between ELMs. After their immediate appearance, they saturate and then grow on timescales of the pedestal pressure recovery. The subsequent ELMs show strongly localised magnetic Plasma Physics and Controlled Fusion

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Section: Discussion About Edge Stability In 3d Tokamak Geometrymentioning

confidence: 99%

Dynamics of ideal modes and subsequent ELM crashes in 3D tokamak geometry from external magnetic perturbations

Willensdorfer

Cote

Griener

et al. 2018

Plasma Phys. Control. Fusion

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“…Nevertheless, dedicated studies using 3D stability calculations of e.g. PBM [31], KBM [32], DW [29] are needed to pin down their role and the role of the 3D equilibrium in the ELM mitigation/suppression. Finally, we would like to point out that the described mechanism is solely based on single fluid ideal MHD physics and does not invoke any mode penetration [5] or ergodization [33].…”

mentioning

confidence: 99%

Field-Line Localized Destabilization of Ballooning Modes in Three-Dimensional Tokamaks

et al. 2017

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Field-line localized ballooning modes have been observed at the edge of high confinement mode plasmas in ASDEX Upgrade with rotating 3D perturbations induced by an externally applied n ¼ 2 error field and during a moderate level of edge localized mode mitigation. The observed ballooning modes are localized to the field lines which experience one of the two zero crossings of the radial flux surface displacement during one rotation period. The localization of the ballooning modes agrees very well with the localization of the largest growth rates from infinite-n ideal ballooning stability calculations using a realistic 3D ideal magnetohydrodynamic equilibrium. This analysis predicts a lower stability with respect to the axisymmetric case. The primary mechanism for the local lower stability is the 3D distortion of the local magnetic shear.

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“…To test this hypothesis, models must be developed capable of mapping the P-B linear stability space of highly shaped experimental 3D equilibria including rotation, and the stability maps of high and low δ U 3D equilibria compared. Several such models have been developed [48], or are near completion [49][50][51].…”

Section: Possible Breaking Of Correlation Between Peelingmentioning

confidence: 99%

Numerical survey of predicted peeling response in edge localised mode mitigated and suppressed phases on ASDEX upgrade

Ryan

Dunne

Kirk

et al. 2019

Plasma Phys. Control. Fusion

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Using the MARS-F linear MHD code (Liu et al 2000 Phys. Plasmas 7 3681), a numerical survey of the plasma response to applied RMPs in ASDEX Upgrade ELM control experiments is conducted, to clarify the role of triangularity and the peeling response in the suppression mechanism. The peeling response is found to decrease with increasing triangularity, due to an increase in the coil-plasma gap reducing the effective vacuum field. Therefore the prior hypothesis that the requirement of high triangularity for suppression access is due to the requirement of a sufficiently large peeling response[2] is suspected to be incorrect. A secondary hypothesis is proposed, that in high triangularity the drive of the resonant response by the peeling response may be boosted by enhanced poloidal harmonic coupling, which could explain the requirement of high triangularity for suppression access. It is shown that in fact the poloidal harmonic coupling between the resonant and off-resonant components decreases with triangularity, and therefore this hypothesis is also rejected. Finally an alternative hypothesis is discussed, that high triangularity is required to access suppression because the associated enhanced pedestal stability allows the edge deformation to be large enough to control the density, without the reduction in stability due to boundary deformation destabilising ELMs. A rigorous test of this hypothesis requires models to be developed to compute the stability of experimental 3D equilibria.

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PB3D: A new code for edge 3-D ideal linear peeling-ballooning stability

Cited by 6 publications

References 21 publications

Dynamics of ideal modes and subsequent ELM crashes in 3D tokamak geometry from external magnetic perturbations

Dynamics of ideal modes and subsequent ELM crashes in 3D tokamak geometry from external magnetic perturbations

Field-Line Localized Destabilization of Ballooning Modes in Three-Dimensional Tokamaks

Numerical survey of predicted peeling response in edge localised mode mitigated and suppressed phases on ASDEX upgrade

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