Experimental analyses and predictive simulations of toroidal rotation driven by the neoclassical toroidal viscosity in rippled tokamaks

Honda, M.; Satake, S.; Suzuki, Yasuhiro; Matsunaga, G.; Shinohara, K.; Yoshida, M.; Matsuyama, Akinobu; Ide, S.; Urano, H.

doi:10.1088/0029-5515/54/11/114005

Cited by 17 publications

(30 citation statements)

References 59 publications

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“…11,12 Above all, the neoclassical toroidal viscosity (NTV), stemming from a three dimensional magnetic field perturbation, was found to have a significant impact on the plasma torque driving the edge toroidal flow. 13,14 As discussed in Ref. 13, the NTV exhibits a strong dependence on E r , and, hence, the knowledge of the edge E r structure (including, in particular, the separatrix) based on precise experimental measurements is imperative for understanding and predicting various transport phenomena in future burning plasma devices.…”

Section: Introductionmentioning

confidence: 99%

Boundary condition for toroidal plasma flow imposed at the separatrix in high confinement JT-60U plasmas with edge localized modes and the physics process in pedestal structure formation

et al. 2014

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Modulation charge eXchange recombination spectroscopy measurements with high spatial and temporal resolution have made the evaluation of the toroidal plasma flow of fully stripped carbon impurity ions (V C6þ / ) in the JT-60U tokamak peripheral region (including, in particular, the separatrix) possible with a better signal-to-noise ratio. By comparing co-and counter-neutral beam injection discharges experimentally, we have identified the boundary condition of V C6þ / and radial electric field shear (rE r ) imposed at the separatrix in high confinement (H-mode) plasmas with edge localized modes (ELMs). The V C6þ / value at the separatrix is not fixed at zero but varies with the momentum input direction. On the other hand, the rE r value is nearly zero (or very weakly positive) at the separatrix. Furthermore, the edge localized mode perturbation does not appear to affect both V C6þ / and rE r values at the separatrix as strongly as that in the pedestal region. The above experimental findings based on the precise edge measurements have been used to validate a theoretical model and develop a new empirical model. A better understanding of the physical process in the edge transport barrier (ETB) formation due to the sheared E r formation is also discussed. V C 2014 AIP Publishing LLC. [http://dx.

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Section: Introductionmentioning

confidence: 99%

Boundary condition for toroidal plasma flow imposed at the separatrix in high confinement JT-60U plasmas with edge localized modes and the physics process in pedestal structure formation

et al. 2014

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“…Such further development can build upon the significant existing literature on NTV (e.g., Refs. [16][17][18][19][20][21][22][23][24][25][26][27][28] to represent the radial magnetic fields produced by field ripple, instabilities, field error, etc., and to model various mechanisms for producing parallel viscosity (i.e., for modeling g 0 ).…”

Section: Summary and Discussionmentioning

confidence: 99%

“…16,[21][22][23][24] Various specific axisymmetric and nonaxisymmetric coordinate systems can be found in the literature. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]…”

Section: Coordinate Systemmentioning

confidence: 99%

Extension of the flow-rate-of-strain tensor formulation of plasma rotation theory to non-axisymmetric tokamaks

Stacey

Bae

2015

Physics of Plasmas

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A systematic formalism for the calculation of rotation in non-axisymmetric tokamaks with 3D magnetic fields is described. The Braginskii Xs-ordered viscous stress tensor formalism, generalized to accommodate non-axisymmetric 3D magnetic fields in general toroidal flux surface geometry, and the resulting fluid moment equations provide a systematic formalism for the calculation of toroidal and poloidal rotation and radial ion flow in tokamaks in the presence of various non-axisymmetric "neoclassical toroidal viscosity" mechanisms. The relation among rotation velocities, radial ion particle flux, ion orbit loss, and radial electric field is discussed, and the possibility of controlling these quantities by producing externally controllable toroidal and/or poloidal currents in the edge plasma for this purpose is suggested for future investigation. V

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“…Alcator C-MOD [9], DIII-D [10,11], JT-60U [12], and the National Spherical Tokamak Experiment (NSTX) [13].…”

Section: Introductionmentioning

confidence: 99%

Rotation and neoclassical ripple transport in ITER

Paul¹,

Landreman²,

Poli³

et al. 2017

Nucl. Fusion

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Neoclassical transport in the presence of non-axisymmetric magnetic fields causes a toroidal torque known as neoclassical toroidal viscosity (NTV). The toroidal symmetry of ITER will be broken by the finite number of toroidal field coils and by test blanket modules (TBMs). The addition of ferritic inserts (FIs) will decrease the magnitude of the toroidal field ripple. 3D magnetic equilibria with toroidal field ripple and ferromagnetic structures are calculated for an ITER steadystate scenario using the Variational Moments Equilibrium Code (VMEC). Neoclassical transport quantities in the presence of these error fields are calculated using the Stellarator Fokker-Planck Iterative Neoclassical Conservative Solver (SFINCS). These calculations fully account for E r , flux surface shaping, multiple species, magnitude of ripple, and collisionality rather than applying approximate analytic NTV formulae. As NTV is a complicated nonlinear function of E r , we study its behavior over a plausible range of E r . We estimate the toroidal flow, and hence E r , using a semi-analytic turbulent intrinsic rotation model and NUBEAM calculations of neutral beam torque.The NTV from the |n| = 18 ripple dominates that from lower n perturbations of the TBMs. With the inclusion of FIs, the magnitude of NTV torque is reduced by about 75% near the edge. We present comparisons of several models of tangential magnetic drifts, finding appreciable differences only for superbanana-plateau transport at small E r . We find the scaling of calculated NTV torque with ripple magnitude to indicate that ripple-trapping may be a significant mechanism for NTV in ITER. The computed NTV torque without ferritic components is comparable in magnitude to the NBI and intrinsic turbulent torques and will likely damp rotation, but the NTV torque is significantly reduced by the planned ferritic inserts. * ejpaul@umd.edu

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Experimental analyses and predictive simulations of toroidal rotation driven by the neoclassical toroidal viscosity in rippled tokamaks

Cited by 17 publications

References 59 publications

Boundary condition for toroidal plasma flow imposed at the separatrix in high confinement JT-60U plasmas with edge localized modes and the physics process in pedestal structure formation

Boundary condition for toroidal plasma flow imposed at the separatrix in high confinement JT-60U plasmas with edge localized modes and the physics process in pedestal structure formation

Extension of the flow-rate-of-strain tensor formulation of plasma rotation theory to non-axisymmetric tokamaks

Rotation and neoclassical ripple transport in ITER

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