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Thermodynamic approach to transport scalings in tokamaks

Published online by Cambridge University Press:  13 March 2009

T. Yamagishi
Affiliation:
GA Technologies Inc., San Diego, California 92138, U.S.A.

Abstract

The cross-field plasma diffusion coefficient is expressed in terms of the perturbed potential energy W by making use of the nonlinearity of orbit diffusion. The thermodynamic bound of the energy W for a current-carrying collisionless plasma has been determined consistently with four constraints: the invariance of averaged Hamiltonian, angular momentum, entropy and density. It is found that with momentum invariance the major contribution from the plasma current cancels, and the lowest upper bound of W is determined by the high-order toroidal effect coupled with the plasma current, which yields the neo-Alcator (TFTR) scaling for the energy confinement time. When neoclassical deformation is allowed in the plasma distribution, the thermodynamic bound has additional terms which come from the neoclassical source of free energy due to the bootstrap current. When the poloidal beta is larger than a certain critical value, the energy confinement time shows the effect of density saturation, and becomes proportional to the plasma current.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1986

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References

REFERENCES

Berk, H. L. & Galeev, A. A. 1967 Phys. Fluids, 10, 441.CrossRefGoogle Scholar
Davidson, R. C. & Tsai, S. I. 1973 J. Plasma Phys. 9, 101.CrossRefGoogle Scholar
Dupree, T. H. 1967 Phys. Fluids, 10, 1049.CrossRefGoogle Scholar
Ejima, S. et al. 1982 Nucl. Fusion, 22, 1627.CrossRefGoogle Scholar
Fowler, T. K. 1968 Advances in Plasma Physics (ed. Simon, A. & Thompson, W. B.), vol. 2, p. 201. Interscience.Google Scholar
Goldstone, R. J. 1984 Plasma Phys. Contr. Fusion, 26, 87.CrossRefGoogle Scholar
Hirshman, S. P. & Molvig, K. 1979 Phys. Rev. Lett. 42, 648.CrossRefGoogle Scholar
Horton, W. 1984 Basic Plasma Physics II (ed. Galeev, A. A. & Sudan, R. N.), p. 402. Elsevier Science Publishers.Google Scholar
Kaye, S. M. 1985 Phys. Fluids, 28, 2327.CrossRefGoogle Scholar
Motojima, O. 1982 U.S.-Japan Workshop on Tokamaks and Stellarators, Massachusetts Institute of Technology.Google Scholar
Ohkawa, T. 1985 Comm. Plasma Phys. Contr. Fusion, 9, 127.Google Scholar
Ohkawa, T. et al. 1985 Proceedings of 12th European Conference on Controlled Fusion and Plasma Physics, Budapest.Google Scholar
Pfeiffer, W. & Waltz, R. E. 1979 Nucl. Fusion, 18, 51.CrossRefGoogle Scholar
Wolfe, S. M. et al. 1983 Nucl. Fusion Suppl. 2, 27.Google Scholar
Yamagishi, T. 1979 Phys. Fluids, 22, 2431.CrossRefGoogle Scholar
Yamagishi, T. 1986 a Plasma Phys. Contr. Fusion, 29, 453.CrossRefGoogle Scholar
Yamagishi, T. 1986 b Phys. Fluids, 29, 594.CrossRefGoogle Scholar