A gyro-Landau-fluid transport model

Waltz, R. E.; Staebler, G. M.; Dorland, W.; Hammett, G. W.; Kotschenreuther, M.; Konings, J. A.

doi:10.1063/1.872228

Cited by 524 publications

(612 citation statements)

References 20 publications

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“…(12) Hammett and Perkins, 1990;Chang and Callen, 1992;Dorland and Hammett, 1993;Beer and Hummett, 1996;and Waltz et al, 1997. There are many calculations for the nonadiabatic electron response based on the truncated chain of electron hydrodynamic equations (Braginskii, 1965;Horton and Varma, 1972) and on the kinetic equations Kadomtsev and Pogutse, 1979;. The general results are complicated by the distinction between the trapped and passing electron orbits and the collisionally broadened resonances of the electron guiding center drift orbits with the wave.…”

Section: Drift-wave Mechanism a Plasma Convection In Quasineutramentioning

confidence: 99%

“…The relation of shear flow stabilization versus the onset of the Kelvin-Helmholtz instability is given in that work. Tokamak-focused simulations showing evidence for the commonly employed ͉v E Ј ͉ϭ␥ max transport suppression rule begin with Waltz, Kerbel, and Milovich (1994) and are followed up in Waltz et al (1997).…”

Section: Scaling Laws Of the Ion Temperature Gradient Turbulent Trmentioning

confidence: 99%

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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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Section: Drift-wave Mechanism a Plasma Convection In Quasineutramentioning

confidence: 99%

Section: Scaling Laws Of the Ion Temperature Gradient Turbulent Trmentioning

confidence: 99%

Drift waves and transport

1999

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“…Predictive modeling 15 using both scaled-experimental 16 and theory-based GLF23 14 transport models indicated that increasing the neutral beam power would result in plasmas reaching a noninductive current fraction f NI Ϸ 100% at higher ␤. Experiments in 2003 were carried out to test these predictions.…”

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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“…For turbulent transport it is then often less instructive to compare arbitrarily defined "conductive" diffusion coefficients than to compare the measured total flux with the predicted total flux. 15 This is exemplified by Eq. (27), the expression for the energy flux.…”

Section: Conclusion and Summarymentioning

confidence: 99%

The effect of turbulent stresses on the experimental determination of a thermal diffusivity due to turbulent transport

Baker¹

2003

Plasma Phys. Control. Fusion

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In plasmas where the transport processes are dominated by turbulence, it is not always straightforward to identify the magnitude of the experimental transport diffusion coefficients. This is primarily due to the fact that with turbulent transport, the separation of the convective and conductive terms depends upon the type of turbulence and/or the model which is used to describe it. For the energy transport it is not just a matter of deciding whether the convection term is 5/2 or 3/2 times the product of the particle flux and the temperature. It is also important to identify turbulence generated convection terms such as heat pinches which can obscure the correct evaluation of the thermal diffusivity. Here we show that inclusion of the turbulence induced stresses into the transport model identifies a heat pinch term and changes the expression for the thermal diffusivity. Comparison with experimental results shows that the new calculated ion thermal diffusivity is no longer less than the neoclassical value even for plasmas with very good ion thermal confinement.

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A gyro-Landau-fluid transport model

Cited by 524 publications

References 20 publications

Drift waves and transport

Drift waves and transport

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

The effect of turbulent stresses on the experimental determination of a thermal diffusivity due to turbulent transport

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