Characterisation of the fast-ion edge resonant transport layer induced by 3D perturbative fields in the ASDEX Upgrade tokamak through full orbit simulations

Sanchis-Sanchez, L.; García-Muñoz, M.; Snicker, A.; Ryan, D. A.; Zarzoso, D.; Chen, L.; Galdón-Quiroga, J.; Nocente, M.; Rivero-Rodriguez, J. F.; Rodriguez-Ramos, M.; Suttrop, W.; Zeeland, M. A. Van; Viezzer, E.; Willensdorfer, M.; Zonca, F.

doi:10.1088/1361-6587/aaef61

Cited by 39 publications

(76 citation statements)

References 28 publications

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“…To identify the resonances responsible for the fast-ion losses the particle resonances can be expressed as [36,37,27]:…”

Section: Identification Of Resonances Responsible For Fast-ion Transportmentioning

confidence: 99%

“…Previous work has shown that linear and nonlinear resonant interactions between fastions and the RMP fields in the region near the separatrix lead to an edge resonant transport layer (ERTL) that is responsible for the observed fast-ion transport in AS-DEX Upgrade [27]. To characterize the RMP-induced transport, the variation of the particle toroidal canonical momentum (P φ ) caused by the broken magnetic symmetry was used as a figure of merit.…”

Section: Introductionmentioning

confidence: 99%

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Optimizing beam-ion confinement in ITER by adjusting the toroidal phase of the 3D magnetic fields applied for ELM control

Sanchis-Sanchez¹,

García-Muñoz²,

Viezzer³

et al. 2021

Nucl. Fusion

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The confinement of Neutral Beam Injection (NBI) particles in the presence of n=3 Resonant Magnetic Perturbations (RMPs) in 15 MA ITER DT plasmas has been studied using full orbit ASCOT simulations. Realistic NBI distribution functions, and 3D wall and equilibria, including the plasma response to the externally applied 3D fields calculated with MARS-F, have been employed. The observed total fastion losses depend on the poloidal spectra of the applied n=3 RMP as well as on the absolute toroidal phase of the applied perturbation with respect to the NBI birth distribution. The absolute toroidal phase of the RMP perturbation does not affect the ELM control capabilities, which makes it a key parameter in the confinement optimization. The physics mechanisms underlying the observed fast-ion losses induced by the applied 3D fields have been studied in terms of the variation of the particle canonical angular momentum (δP φ ) induced by the applied 3D fields. The presented simulations indicate that the transport is located in an Edge Resonant Transport Layer (ERTL) as observed previously in ASDEX Upgrade studies. Similarly, our results indicate that an overlapping of several linear and nonlinear resonances at the edge of the plasma might be responsible for the observed fast-ion losses. The results presented here may help to optimize the RMP configuration with respect to the NBI confinement in future ITER discharges.

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“…To identify the resonances responsible for the fast-ion losses the particle resonances can be expressed as [36,37,27]:…”

Section: Identification Of Resonances Responsible For Fast-ion Transportmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimizing beam-ion confinement in ITER by adjusting the toroidal phase of the 3D magnetic fields applied for ELM control

Sanchis-Sanchez¹,

García-Muñoz²,

Viezzer³

et al. 2021

Nucl. Fusion

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“…However, the reliability and usefulness of this statistic method in identifying resonance between lost fast ions and RMPs needs to be further explored. Most authors analyze fast ion transport in terms of the variation of the toroidal canonical momentum, δP φ , which is a more informative figure of merit than the simple condition of loss or not (used in this work), in revealing the resonance between fast-ions and magnetic perturbations 18 .…”

Section: Summary and Discussionmentioning

confidence: 99%

“…This coils turn out to also have effects on the transport of neutral beam fast ions [11][12][13][14][15] . The effects of RMPs on fast ion transport and loss have been extensively investigated on AUG [16][17][18] , KSTAR 19 , DIII-D 20,21 , and MAST 22 tokamaks.…”

Section: Introductionmentioning

confidence: 99%

Effects of resonant magnetic perturbations on neutral beam heating in a tokamak

Hu,

Xu,

Hao

et al. 2021

Preprint

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Effects of resonant magnetic perturbations (RMPs) on tangential neutral beam heating in the EAST tokamak are studied numerically. RMPs with linear resistive magnetohydrodynamics response are used in the modeling. A variety of representing configurations of RMP coil currents are examined and their effects on the NBI heating efficiency are compared, in order to find a parameter window where deleterious effects of RMPs on NBI heating efficiency are minimized. It is found that the internal redistribution of fast ions by RMPs induces local accumulation of fast ions, resulting in higher local fast ion pressure than the case without RMPs. It is also found that the toroidal phasing of the RMP with respect to the fast ion source has slight effects on the steady-state radial profile of fast ions. The dependence of fast ion loss fraction on the RMP up-down phase difference shows similar behavior as the dependence of the radial width of chaotic magnetic field on the phase difference. A statistical method of identifying resonances between RMPs and lost fast ions is proposed and the results indicate that some resonances between RMPs and lost passing particles may be of non-integer fractional order, rather than the usual integer order.

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“…14 In addition, further work should consider the impact of externally applied three-dimensional magnetic field perturbations, such as those used for edge-localized mode control, which could cause significant alpha transport (Sanchis et al. 2018).…”

Section: Ripple Fluxmentioning

confidence: 99%

Drift kinetic theory of alpha transport by tokamak perturbations

Tolman

Catto

2021

J. Plasma Phys.

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Upcoming tokamak experiments fuelled with deuterium and tritium are expected to have large alpha particle populations. Such experiments motivate new attention to the theory of alpha particle confinement and transport. A key topic is the interaction of alpha particles with perturbations to the tokamak fields, including those from ripple and magnetohydrodynamic modes like Alfvén eigenmodes. These perturbations can transport alphas, leading to changed localization of alpha heating, loss of alpha power and damage to device walls. Alpha interaction with these perturbations is often studied with single-particle theory. In contrast, we derive a drift kinetic theory to calculate the alpha heat flux resulting from arbitrary perturbation frequency and periodicity (provided these can be studied drift kinetically). Novel features of the theory include the retention of a large effective collision frequency resulting from the resonant alpha collisional boundary layer, correlated interactions over many poloidal transits and finite orbit effects. Heat fluxes are considered for the example cases of ripple and the toroidal Alfvén eigenmode (TAE). The ripple heat flux is small. The TAE heat flux is significant and scales with the square of the perturbation amplitude, allowing the derivation of constraints on mode amplitude for avoidance of significant alpha depletion. A simple saturation condition suggests that TAEs in one upcoming experiment will not cause significant alpha transport via the mechanisms in this theory. However, saturation above the level suggested by the simple condition, but within numerical and experimental experience, which could be accompanied by the onset of stochasticity, could cause significant transport.

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Characterisation of the fast-ion edge resonant transport layer induced by 3D perturbative fields in the ASDEX Upgrade tokamak through full orbit simulations

Cited by 39 publications

References 28 publications

Optimizing beam-ion confinement in ITER by adjusting the toroidal phase of the 3D magnetic fields applied for ELM control

Optimizing beam-ion confinement in ITER by adjusting the toroidal phase of the 3D magnetic fields applied for ELM control

Effects of resonant magnetic perturbations on neutral beam heating in a tokamak

Drift kinetic theory of alpha transport by tokamak perturbations

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