Modelling of Ion Kinetic Effects for SOL Flow Formation

Takizuka, T.; Hoshino, Kazuo; Shimizu, K.; Yagi, M.

doi:10.1002/ctpp.201010044

Cited by 11 publications

(9 citation statements)

References 19 publications

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“…The change in the direction of the SOL flow at the LFS midplane with B t (or ion B × ∇B direction) has also been observed in Lmode plasmas in a number of tokamaks, which was attributed to classical drifts and enhanced trans port on LFS [40]. In addition, kinetic modeling shows that the dynamics of trapped particles on the banana orbits may make an important contribution [36,41]. Preliminary modeling of up-down divertor asymmetry during ELMs has recently been carried out with BOUT++ for a DN divertor configuration in EAST, and verified the strong impact of drifts [19].…”

Section: Discussionmentioning

confidence: 85%

In–out asymmetry of divertor particle flux in H-mode with edge localized modes on EAST

et al. 2016

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The in–out divertor asymmetry in the Experimental Advanced Superconducting Tokamak (EAST), as manifested by particle fluxes measured by the divertor triple Langmuir probe arrays, is significantly enhanced during type-I edge localized modes (ELMs), favoring the inner divertor in lower single null (LSN) for the normal toroidal field (B t) direction, i.e. with the ion B × ∇ B direction towards the lower X-point, while the in–out asymmetry is reversed when the ion B × ∇ B is directed away from the lower X-point. The plasma flow measured by the Mach probe at the outer midplane is in the ion Pfirsch–Schlüter (PS) flow direction, opposite to both B × ∇ B and E × B drifts, i.e. towards the inner divertor for normal B t, and the outer divertor for reverse B t, consistent with the observed in–out divertor asymmetry in particle fluxes. Since the particle source from an ELM event is predominantly located near the outer midplane, this new finding suggests a critical role of the PS flow in driving the in–out divertor asymmetry. The divertor asymmetry during type-III ELMs exhibits a similar trend to that during type-I ELMs. Strong in–out divertor asymmetry is also present during inter-ELM and ELM-free phases for the normal field direction, i.e. with more particle flux to the lower inner divertor target, but the peak particle flux merely becomes more symmetric, or slightly reversed, for reverse B t, i.e. reversed B × ∇ B drift direction.

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Section: Discussionmentioning

confidence: 85%

In–out asymmetry of divertor particle flux in H-mode with edge localized modes on EAST

et al. 2016

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“…The SOL-divertor fluid modeling has to include finite orbiting effect as well as transport coefficients valid for collision less regime not based on Braginskii fluid mode such as thermal force. [15]. Both for a case of ion ∇B drift away from X point.…”

Section: Narrow Heat Channel In the H-mode Solmentioning

confidence: 97%

“…Takizuka [21], [15] showed by the particle simulation that the parallel convective heat flux could be enhanced by the SOL flow acceleration due to the ion orbit excursion across the separatrix up to u ∼ 0.5C s . Fig.4 a) shows a schematic view of the flow pattern in tokamak in the case of ion ∇B drift away from the X point.…”

Section: Narrow Heat Channel In the H-mode Solmentioning

confidence: 99%

Negative Triangularity Tokamak as Fusion Energy System

Kikuchi¹,

Fasoli

Takizuka

et al. 2014

Proceedings of 1st International E-Conference on Energies

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Fusion energy development is quite successful in both getting equivalent energy break-even condition in large tokamak and clarifying many important physics in the magnetically confined plasma to proceed to a fusion experimental reactor, ITER [12]. Now, fusion research has to solve the power handling toward fusion demonstration power reactor (DEMO). A tokamak plasma with strongly negative triangularity may offer such an opportunity as an innovative concept [2]. Experimental and theoretical works at CRPP-EPFL shows promising results for negative triangularity tokamak [31]. In this paper, we review the current understanding of such configuration in both physical and technological aspects.

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“…destabilizing) contribution to the perturbed MHD potential energy. Therefore, the presence of a large fraction of the bad curvature region often leads to the bursting of large edge localized modes (ELMs) when the plasma is operated in the so called H-mode regime [4][5][6][7]. Due to the potentially harmful damage that these large perturbations can cause to the plasma facing components, ELMs have to be controlled in (future) tokamak devices, either passively or actively.…”

Section: Plasma Physics and Controlled Fusionmentioning

confidence: 99%

A comparative study of ideal kink stability in two reactor-relevant tokamak plasma configurations with negative and positive triangularity

Ren

Liu

et al. 2016

Plasma Phys. Control. Fusion

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The effects of an ideal/resistive conducting wall, the drift kinetic resonances, as well as the toroidal plasma flow, on the stability of the ideal external kink mode are numerically investigated for a reactor-relevant tokamak plasma with strongly negative triangularity (NTR) shaping. Comparison is made for a similar plasma equilibrium, but with positive triangularity (PTR). It is found that the ideal wall stabilization is less efficient for the kink stabilization in the NTR plasma due to a less 'external' eigenmode structure compared to the PTR plasma. The associated plasma displacement in the NTR plasma does not 'balloon' near the outboard mid-plane, as is normally the case for the pressure-driven kink-ballooning instability in PTR plasmas, but being more pronounced near the X-points. The toroidal flow plays a similar role for the kink stability for both NTR and PTR plasmas. The drift kinetic damping is less efficient for the ideal external kink mode in the NTR plasma, despite a somewhat larger fraction of the particle trapping near the plasma edge compared to the PTR equilibrium. However, the drift kinetic damping of the resistive wall mode (RWM) in the NTR plasma is generally as efficient as that of the PTR plasma, although the RWM window, in terms of the normalized pressure, is narrower for the NTR plasma.

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Modelling of Ion Kinetic Effects for SOL Flow Formation

Cited by 11 publications

References 19 publications

In–out asymmetry of divertor particle flux in H-mode with edge localized modes on EAST

In–out asymmetry of divertor particle flux in H-mode with edge localized modes on EAST

Negative Triangularity Tokamak as Fusion Energy System

A comparative study of ideal kink stability in two reactor-relevant tokamak plasma configurations with negative and positive triangularity

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