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High-beta turbulence in two-dimensional magnetohydrodynamics

Published online by Cambridge University Press:  13 March 2009

David Fyfe
Affiliation:
Applied Mathematical Sciences Program
David Montgomery
Affiliation:
Department of Physics and Astronomy, The University of Iowa, Iowa City, Iowa 52242

Abstract

Incompressible turbulent flows are investigated in the framework of ideal magnetohydrodynamics. All the field quantities vary with only two spatial dimensions. Equilibrium canonical distributions are determined in a phase space whose co-ordinates are the real and imaginary parts of the Fourier coefficients for the field variables. In the geometry considered, the magnetic field and fluid velocity have variable x and y components, and all field quantities are independent of z. Three constants of the motion are found (one of them new) which survive the truncation in Fourier space and permit the construction of canonical distributions with three independent temperatures. Spectral densities are calculated. One of the more novel physical effects is the appearance of macroscopic structures involving long wavelength, self-generated, magnetic fields (‘magnetic islands’) for a wide range of initial parameters. Current filaments show a tendency toward consolidation in much the same way that vorticity filaments do in the guiding-centre plasma case. In the presence of finite dissipation, energy cascades to higher wavenumbers can be accompanied by vector potential cascades to lower wavenumbers, in much the same way as, in the fluid dynamic (Navier-Stokes) case, energy cascades to lower wavenumbers accompany enstrophy cascades to higher wavenumbers. It is suggested that the techniques may be relevant to theories of the magnetic dynamo problem and to the generation of megagauss magnetic fields when pellets are irradiated by lasers.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1976

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References

REFERENCES

Basdevant, C. & Sadourny, R. 1975 J. Fluid Mech. 69, 673.CrossRefGoogle Scholar
Book, D. L., McDonald, B. E. & Fisher, S. 1975 Phys. Rev. Lett. 34, 4.CrossRefGoogle Scholar
Frisch, U., Pouquet, A., Léorat, J. & Mazure, A. 1975 J. Fluid Mech. 68, 769.CrossRefGoogle Scholar
Herring, J. R., Orszag, S. A., Kraichnan, R. H. & Fox, D. G. 1974 J. Fluid Mech. 66, 417.CrossRefGoogle Scholar
Joyce, G. & Montgomery, D. 1973 J. Plasma Phys. 10, 107.CrossRefGoogle Scholar
Kraichnan, R. H. 1967 Phys. Fluids, 10, 1417.CrossRefGoogle Scholar
Kraichnan, R. H. 1975 J. Fluid Mech. 67, 155.CrossRefGoogle Scholar
Lee, R. & Lampe, M. 1973 Phys. Rev. Lett. 31, 1390.CrossRefGoogle Scholar
Lundgren, T. S. & Pointin, Y. B. 1975 Statistical Mechanics of Two-Dimensional Vortices. To be published.Google Scholar
McDonald, B. E. 1974 J. Comp. Phys. 16, 360.CrossRefGoogle Scholar
Montgomery, D. 1972 Phys. Lett. A39, 7.CrossRefGoogle Scholar
Montgomery, D. 1975 Plasma Physics: Les Houches 1972 (ed. de Witt, C. & Peyraud, J.), pp. 427535. Gordon & Breach.Google Scholar
Montgomery, D. 1976 Physica, 82C, 111.Google Scholar
Montgomery, D. & Joyce, G. 1974 Phys. Fluids, 17, 1139.CrossRefGoogle Scholar
Montgomery, D. & Salu, Y. 1975 Bull. Am. Phys. Soc. Ser. II, 20, 1310.Google Scholar
Onsager, L. 1949 Nuovo Cimento Suppl. 6, 279.CrossRefGoogle Scholar
Orszag, S. A. 1973 Proceedings of the 1973 Les Houches Summer School of Theoretical Physics (to be published), section 1.2.Google Scholar
Pointin, Y. B. & Lundgren, T. S. 1975 Statistical Mechanics of Two-Dimensional Vortices in a Bounded Container. To be published (University of Minnesota preprint).Google Scholar
Schumann, U. 1975 Numerical Solution of the Transition from Three- to Two-Dimensional Turbulence Under a Uniform Magnetic Field. To be published.Google Scholar
Seyler, C. E. 1974 Phys. Rev. Lett. 32, 515.CrossRefGoogle Scholar
Seyler, C. E., Salu, Y., Montgomery, D. & Knorr, G. 1975 Phys. Fluids, 18, 803.CrossRefGoogle Scholar
Tappert, F. & Hardin, R. 1971 Film: Computer-Simulated MHD Turbulence. Bell Laboratories.Google Scholar
Taylor, J. B. & McNamara, B. 1971 Phys. Fluids, 14, 1492.CrossRefGoogle Scholar
Ter Haar, D. 1967 Elements of Thermostatistics, 2nd Ed. Ch. 1–3. Holt, Rinehart & Winston.Google Scholar
Woltjer, L. 1958 Proc. Natn. Acad. Sci. U.S.A. 44, 489.CrossRefGoogle Scholar