Bootstrap current and neoclassical transport in tokamaks of arbitrary collisionality and aspect ratio

Houlberg, W. A.; Shaing, K. C.; Hirshman, S. P.; Zarnstorff, M. C.

doi:10.1063/1.872465

Cited by 603 publications

(631 citation statements)

References 38 publications

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“…This torque measurement procedure is repeated for several similar discharges, with different Ω C values on the ρ = 0.67 surface. The resultant total NTV torque as a function of the deuterium toroidal rotation rate, Ω D , (calculated from Ω C using NCLASS [19]) at the ρ = 0.67 surface is plotted with diamonds in Fig. 3 and clearly shows a peak.…”

Section: Observation Of Peak Neoclassical Toroidal Viscous Force In Tmentioning

confidence: 99%

Observation of Peak Neoclassical Toroidal Viscous Force in the DIII-D Tokamak

et al. 2011

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Section: Observation Of Peak Neoclassical Toroidal Viscous Force In Tmentioning

confidence: 99%

Observation of Peak Neoclassical Toroidal Viscous Force in the DIII-D Tokamak

et al. 2011

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“…The bootstrap current is estimated to be 59% with the Sauter model 20 and NCLASS model. 21 These models are somewhat sensitive to the input profiles near the axis and edge. The neutral beam current drive fraction is calculated to be 31% from the TRANSP Monte-Carlo beam slowing down calculation, and ECCD calculated by TORAY-GA code 22 is 8%.…”

Section: Characteristics Of 100% Noninductive High ␤ Dischargesmentioning

confidence: 99%

Progress toward fully noninductive, high beta conditions in DIII-D

et al. 2006

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The DIII-D Advanced Tokamak ͑AT͒ program in the DIII-D tokamak ͓J. L. Luxon, Plasma Physics and Controlled Fusion Research, 1986, Vol. I ͑International Atomic Energy Agency, Vienna, 1987͒, p. 159͔ is aimed at developing a scientific basis for steady-state, high-performance operation in future devices. This requires simultaneously achieving 100% noninductive operation with high self-driven bootstrap current fraction and toroidal beta. Recent progress in this area includes demonstration of 100% noninductive conditions with toroidal beta, ␤ T = 3.6%, normalized beta, ␤ N = 3.5, and confinement factor, H 89 = 2.4 with the plasma current driven completely by bootstrap, neutral beam current drive, and electron cyclotron current drive ͑ECCD͒. The equilibrium reconstructions indicate that the noninductive current profile is well aligned, with little inductively driven current remaining anywhere in the plasma. The current balance calculation improved with beam ion redistribution that was supported by recent fast ion diagnostic measurements. The duration of this state is limited by pressure profile evolution, leading to magnetohydrodynamic ͑MHD͒ instabilities after about 1 s or half of a current relaxation time ͑ CR ͒. Stationary conditions are maintained in similar discharges ͑ϳ90% noninductive͒, limited only by the 2 s duration ͑1 CR ͒ of the present ECCD systems. By discussing parametric scans in a global parameter and profile databases, the need for low density and high beta are identified to achieve full noninductive operation and good current drive alignment. These experiments achieve the necessary fusion performance and bootstrap fraction to extrapolate to the fusion gain, Q = 5 steady-state scenario in the International Thermonuclear Experimental Reactor ͑ITER͒ ͓R. Aymar et al., Fusion Energy Conference on Controlled Fusion and Plasma Physics, Sorrento, Italy ͑International Atomic Energy Agency, Vienna, 1987͒, paper IAEA-CN-77/OV-1͔. The modeling tools that have been successfully employed to both plan and interpret the experiment are used to plan future DIII-D experiments with higher power and longer pulse ECCD and fast wave and co-and counterneutral beam injection in a pumped double-null configuration. The models predict our ability to control the current and pressure profiles to reach full noninductivity with increased beta, bootstrap fraction, and duration. The same modeling tools are applied to ITER, predicting favorable prospects for the success of the ITER steady-state scenario.

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“…The moment method of analysis has an advantage for the systematic development of multispecies transport theory (Balescu, 1988 andHoulberg et al, 1997).…”

Section: Scaling Laws Of the Ion Temperature Gradient Turbulent Trmentioning

confidence: 99%

Drift waves and transport

1999

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Drift waves occur universally in magnetized plasmas producing the dominant mechanism for the transport of particles, energy and momentum across magnetic field lines. A wealth of information obtained from quasistationary laboratory experiments for plasma confinement is reviewed for drift waves driven unstable by density gradients, temperature gradients and trapped particle effects. The modern understanding of Bohm transport and the role of sheared flows and magnetic shear in reducing the transport to the gyro-Bohm rate are explained and illustrated with large scale computer simulations. The types of mixed wave and vortex turbulence spontaneously generated in nonuniform plasmas are derived with reduced magnetized fluid descriptions. The types of theoretical descriptions reviewed include weak turbulence theory, Kolmogorov anisotropic spectral indices, and the mixing length. A number of standard turbulent diffusivity formulas are given for the various space-time scales of the drift-wave turbulent mixing. [S0034-6861(99)00803-X] CONTENTS

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Bootstrap current and neoclassical transport in tokamaks of arbitrary collisionality and aspect ratio

Cited by 603 publications

References 38 publications

Observation of Peak Neoclassical Toroidal Viscous Force in the DIII-D Tokamak

Observation of Peak Neoclassical Toroidal Viscous Force in the DIII-D Tokamak

Progress toward fully noninductive, high beta conditions in DIII-D

Drift waves and transport

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