Plasma Diffusion in a Toroidal Stellarator

Galeev, A. A.; Sagdeev, R. Z.; Furth, H. P.; Rosenbluth, M. N.

doi:10.1103/physrevlett.22.511

Cited by 162 publications

(217 citation statements)

References 2 publications

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“…appropriate to the banana regime (3.58) in an asymmetric system (Gibson and Mason, 1969;Galeev, et al , 1969;Frieman, 1970;Hazeltine and Rosenbluth, 1972;Connor and Hastie, 1974). As remarked previously, diffusion across the asymmetrical confining field of a stellerator is more complicated, in that several low collision frequency regimes can be distinguished.…”

Section: Second-order Fluxesmentioning

confidence: 82%

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Theory of plasma transport in toroidal confinement systems

1976

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The dissipation induced by coulomb-collisional scattering provides an irreducible minimum, and thus a useful standard for comparison, for transport processes in a hot, magnetically confined plasma. The kinetic description of this dissipation is provided by an equation of the Fokker -Planck form. As in the standard transport theory for a neutral gas, approximate solution of the Fokker -Planck equation permits the calculation of transport coefficients, which linearly relate the fluxes of particles, energy, and electric charge, to the density and temperature gradients, and to the electric field. The transport relations are useful in studying the confinement properties of present and future experimental devices for research in controlled thermonuclear fusion. The transport theory for a magnetized plasma (in which the Larmor radius is much smaller than gradient scale lengths describing the plasma fluid) departs from the theory for a neutral gas in several fundamental ways. Thus, transport coefficients for a magnetized plasma can be calculated even when the collisional mean free path is much longer than the gradient scale length (as would pertain in thermonuclear regimes). Such transport coefficients are generally nonlocal, being defined in terms of averages over surfaces with macroscopic dimensions. Furthermore, when the mean free path is long, the magnetized-plasma transport coefficients depend crucially upon the magnetic field geometry, the effects of which must be treated at the kinetic level of the Fokker -Planck equation. The results display several novel couplings between collisional dissipation and the electromagnetic field. The present review of magnetizedplasma transport theory is intended to be as widely accessible as possible. Thus the relevant features of magnetic confinement in closed (toroidal) systems, and of charged particles in spatially varying fields, are derived, at least in outline, from first principles. Although consideration is given to "classical" transport in which most field geometric effects are omitted, major emphasis is placed on the "neoclassical" theory which has been developed over the last decade, Neoclassical transport coefficients are specifically relevant to a magnetically confined plasma, rather than to just a magnetized plasma; their unusual features, such as nonlocality and geometry dependence, become particularly important in the high temperature regime of proposed thermonuclear reactors, The area of neoclassical theory which seems most complete -its application to axisymmetric tokamak-type confinement systems -is correspondingly stressed. CONTENTS

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Section: Second-order Fluxesmentioning

confidence: 82%

“…Plasma diffusion in a stellerator was investigated by Galeev, Sagdeev, Furth, and Rosenbluth (1969). They found a maximum in the diffusion coefficient at low collision frequencies, due to the existence of "localized" particles (Gibson and Taylor, 196'l;Gibson and Mason, 1968), with "superbanana" orbits.…”

Section: A Historymentioning

confidence: 99%

Theory of plasma transport in toroidal confinement systems

1976

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“…Non-ambipolar transport has been studied for many years [9][10][11][12][13], and its importance for tokamaks has been recently appreciated [14][15][16]. Two main regimes were thought important in tokamaks, the 1/ν regime [16] when the E × B precession frequency ω E is low relatively to the collision frequency ν, and the ν √ ν regime [17] when ω E is relatively high.…”

Section: Neoclassical Toroidal Viscosity (Ntv)mentioning

confidence: 99%

Nonambipolar Transport by Trapped Particles in Tokamaks

2009

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“…Analytical studies carried out by Frieman and by Connor and Hastie 8 showed that the diffusion coefficient is inversely proportional to the collision frequency v, but they did not correctly include the important effect caused by an ambipolar radial electric field on ion transport* Galeev et al, 9 using a variational principle, and Galeev and Sagdeev, 10 using an expansion technique, showed that the ambipolar field reduces the ion diffusion coefficient, but they did not investigate the ion behavior over a wide energy range and other effects. Extending Galeev's work, Mynick 11 studied the effect on transport of a new nonradial ambipolar electric field.…”

Section: Introductionmentioning

confidence: 99%

Neoclassical transport in stellarators

Kulsrud

1987

The Physics of Fluids

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DISCLAIMERThis report was prepared as an account of work sponsored by an agency of the United Slates Government. Neither the United Stales Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi bility for the accuracy, completeness, or usefulness or any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refer ence herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, rccomraeodalioo, or favoring by the United States Gov**nment or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States GwKtnacat or any agency thereof. + s^irs^.^rasr^5^r^L ab --* <* fisrasuTOij OF IBS mratiii is mmm >> 2 . ABSTRACTThe stellarator neoclassical transport due to particles trapped in local helical wells ig calculated in the low-collisionality regime using a systematic expansion. The behavior of electron transport is found to be the game over a wide range of energies, but the behavior of ion transport for low energy ions is found to be different than that for high energy ions.

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Plasma Diffusion in a Toroidal Stellarator

Cited by 162 publications

References 2 publications

Theory of plasma transport in toroidal confinement systems

Theory of plasma transport in toroidal confinement systems

Nonambipolar Transport by Trapped Particles in Tokamaks

Neoclassical transport in stellarators

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