Numerical validation of the refined formula of neoclassical toroidal plasma viscosity in tokamaks

Sun, Yuan; Shaing, K. C.; Liang, Y.; Shen, Biao; Wan, Baonian

doi:10.1088/0029-5515/53/7/073026

Cited by 24 publications

(20 citation statements)

References 29 publications

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“…The width of the resonance layer can be estimated from the definition for z 1 to be k 2 ≈ ν1/3 1 , and can be used in the argument of the logarithmic function. An accurate numerical evaluation for the layer width can be made using the iteration procedure for the best fit to the numerical solution of the bounce average drift kinetic equation in the transition region [229]. Equation (8.2.4.2.6) is the standard equation for the plateau resonances derived previously.…”

Section: Resonance Away From the Phase Space Boundarymentioning

confidence: 99%

Neoclassical plasma viscosity and transport processes in non-axisymmetric tori

2015

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Neoclassical transport processes are important to the understanding of plasma confinement physics in doubly periodic magnetized toroidal plasmas, especially, after the impact of the momentum confinement on the particle and energy confinement is recognized. Real doubly periodic tori in general are non-axisymmetric, with symmetric tori as a special case. An eight-moment approach to transport theory with plasma density N, plasma pressure p, mass flow velocity V and heat flow q as independent variables is adopted. Transport processes are dictated by the solutions of the momentum and heat flux balance equations. For toroidal plasma confinement devices, the first order (in the gyro-radius ordering) plasma flows are on the magnetic surface to guarantee good plasma confinement and are thus two-dimensional. Two linearly independent components of the momentum equation are required to determine the flows completely. Once this two-dimensional flow is relaxed, i.e. the momentum equation reaches a steady state, plasmas become ambipolar, and all the transport fluxes are determined through the flux-force relation. The flux-force relation is derived both from the kinetic definitions for the transport fluxes and from the manipulation of the momentum and heat flux balance equations to illustrate the nature of the transport fluxes by examining their corresponding driven forces and their roles in the momentum and heat flux balance equations. Steady-state plasma flows are determined by the components of the stress and heat stress tensors in the momentum and heat flux balance equations. This approach emphasizes the pivotal role of the momentum equation in the transport processes and is particularly useful in modelling plasma flows in experiments. The methodology for neoclassical transport theory is applied to fluctuation-driven transport fluxes in the quasilinear theory to unify these two theories. Experimental observations in tokamaks and stellarators for the physics discussed are presented.

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Section: Resonance Away From the Phase Space Boundarymentioning

confidence: 99%

Neoclassical plasma viscosity and transport processes in non-axisymmetric tori

2015

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“…Its ac capability with a frequency up to 1 kHz makes it also useful for resistive wall mode control. Vacuum modelling of the 3D topology, as well as modelling of helical ripple and neoclassical toroidal viscosity (NTV), were also reported [17]. K.J.…”

Section: External 3d Effectsmentioning

confidence: 99%

APTWG: The 4th Asia-Pacific Transport Working Group Meeting

et al. 2014

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This conference report summarizes the contributions to, and discussions at, the 4th Asia-Pacific Transport Working Group Meeting held at Kyushu University, Japan, during 10–13 June 2014. The topics of the meeting were organized under five main headings: turbulence suppression and transport barrier formation, effect of magnetic topology on MHD activity and transport, non-diffusive contribution of momentum and particle transport, non-local transport and turbulence spreading and coupling, energetic particles and instability. The Young Researchers' Forum which was held in this meeting is also described in this report.

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“…The evaluation of NTV torque density depends on the calculation of the perturbed distribution function f 1 and the perturbed magnetic field strength δB along the distorted magnetic surfaces. NTV torque density profile can be written as [13,38,39]:…”

Section: B Ntv Model In Ntvtok Codementioning

confidence: 99%

“…The rest of definitions and the detailed solutions of the above BDKE implemented in the NTVTOK code, both analytical and numerical, can be found in [13,27,38,39]. The calculation of b n , which is the n-th toroidal Fourier component of the perturbed magnetic field strength δB, is described in next subsection (Sec.…”

Section: B Ntv Model In Ntvtok Codementioning

confidence: 99%

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Neoclassical toroidal viscosity torque in tokamak edge pedestal induced by external resonant magnetic perturbation

2017

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The characteristic profile and magnitude are predicted in theory for the neoclassical toroidal viscosity (NTV) torque induced by plasma response to the resonant magnetic perturbation (RMP) in a tokamak with an edge pedestal. For a low-β equilibrium, the NTV torque is dominated by the toroidal component with the same dominant toroidal mode number of RMP. The NTV torque profile is found to be localized, whose peak location is determined by profiles of both the equilibrium temperature (pressure) and the plasma response. In general, the peak of NTV torque profile is found to track the pedestal position. The magnitude of NTV torque strongly depends on the β value of pedestal, which suggests a more significant role of NTV torque in higher plasma β regimes. For a fixed plasma β, decreasing density hence increasing temperature can also enhance the amplitude of NTV torque due to the reduced collisionality in the 1/ν regime. Based on those findings, we identify the tokamak operation regimes where the significance of NTV torque in edge pedestal induced by RMP can approach those from other momentum sources such as the neutral beam injections. *

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Numerical validation of the refined formula of neoclassical toroidal plasma viscosity in tokamaks

Cited by 24 publications

References 29 publications

Neoclassical plasma viscosity and transport processes in non-axisymmetric tori

Neoclassical plasma viscosity and transport processes in non-axisymmetric tori

APTWG: The 4th Asia-Pacific Transport Working Group Meeting

Neoclassical toroidal viscosity torque in tokamak edge pedestal induced by external resonant magnetic perturbation

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