Results 231 to 240 of about 2,986 (264)

Bifurcated neoclassical particle transport

Physics of Plasmas, 1998
The theory of neoclassical transport in an impure, toroidal plasma is extended to allow for steeper pressure and temperature gradients than are usually considered. It is found that the ion particle flux is a nonmonotonic function of these gradients for plasma parameters typical of the tokamak edge.
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Monte-Carlo simulation of neoclassical transport in stellarators

Nuclear Fusion, 1984
Neoclassical transport coefficients are computed by Monte-Carlo simulation over a wide range of mean free paths in the approximation of small-gyroradius, mono-energetic-particle distribution, and vanishing electric field for several stellarator fields. Pfirsch-Schluter, plateau, and ripple transport coefficients are obtained. The transport coefficients
Dommaschk, W., Lotz, W., Nuehrenberg, J.
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Nonlinear neoclassical transport in toroidal edge plasmas

Physics of Plasmas, 2001
In conventional neoclassical theory, the density and temperature gradients are not allowed to be as steep as frequently observed in the tokamak edge. In this paper the theory of neoclassical transport in a collisional, impure plasma is extended to allow for steeper profiles than normally assumed.
T. Fülöp, P. Helander
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Neoclassical transport in the presence of fluctuations

Nuclear Fusion, 1992
The usual argument for automatic ambipolarity of neoclassical particle fluxes in a tokamak is based on the averaged toroidal momentum equation. It does not apply when fluctuations are present, because they also contribute to the momentum. The finite Larmor radius pressure tensor produced by electrostatic fluctuations makes a small contribution to the ...
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Non-ambipolar neoclassical transport

Nuclear Fusion, 1995
The usual demonstration that neoclassical transport is automatically ambipolar, and independent of the radial electric field (Er), is shown to be valid only in an equilibrium axisymmetric plasma in which there is no other source or damping of toroidal momentum.
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Neoclassical transport in the presence of radiofrequency fields

Nuclear Fusion, 1989
The neoclassical fluxes induced by a radiofrequency field are calculated using the gyrokinetic equations. In general, the fluxes consist of a convective part and a diffusive part. The convective part is non-vanishing when the heating is asymmetric with respect to the magnetic field.
S.C. Chiu, V.S. Chan
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Neoclassical Transportation in the ELMO Bumpy Torus

Physical Review Letters, 1978
In the ELMO bumpy torus, neoclassical transport coefficients depend critically on the ambipolar electric field. These coefficients, calculated for arbitrary radial electric fields, are applied in a one-dimensional radial-transport calculation which, for the first time, treats the electric field self-consistently.
E. F. Jaeger, D. A. Spong, C. L. Hedrick
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Drift-Kinetic Simulations of Neoclassical Transport

AIP Conference Proceedings, 2008
We present results from numerical studies of neoclassical transport for multi‐species plasmas. The code, NEO, provides a first‐principles based calculation of the neoclassical transport coefficients directly from solution of the distribution function by solving a hierarchy of equations derived by expanding the fundamental drift‐kinetic equation in ...
E. A. Belli, J. Candy, Olivier Sauter, Xavier Garbet, Elio Sindoni   +4 more
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Neoclassical Transport In The Stellarator And Heliotron

1998
Abstract In neoclassical diffusion theory, the essential mechanism is the existence of a trapped particle with a velocity component perpendicular to the magnetic surfaces due to VB drift motion. From this point of view, neoclassical diffusion exists even in straight stellarators with perfect helical symmetry.
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On the relation between neoclassical transport and turbulent transport

Physics of Plasmas, 2005
It is demonstrated through the flux-force relationship in the neoclassical theory that when neoclassical transport fluxes are improved, the damping rate of the radial electric field of the zonal flow is reduced. This, in turn, leads to improved turbulent transport fluxes.
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