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Surface currents on models of force-free solar magnetic flux tubes

Published online by Cambridge University Press:  13 March 2009

D. B. Melrose
Affiliation:
Research Centre for Theoretical Astrophysics, University of Sydney, NSW 2006, Australia
Jennifer Nicholls
Affiliation:
Research Centre for Theoretical Astrophysics, University of Sydney, NSW 2006, Australia
N. G. Broderick
Affiliation:
Research Centre for Theoretical Astrophysics, University of Sydney, NSW 2006, Australia

Abstract

A model of a cylindrically symmetric, force-free magnetic field consisting of a sequence of concentric layers with piecewise-constant α is used to construct models of the surface currents on isolated, force-free magnetic flux tubes. Two boundary conditions are considered: a current-neutralized flux tube (Bφ = 0, Bz φ 0, Bz ≠ O at r > r0), and an isolated current-carrying flux tube (Bφ0, Bz = 0 at r > r0). A single-a model that is current-neutralized is a reverse-field pinch, and is unacceptable as a model for a solar flux tube. Examples of two-α models for a current-neutralized flux tube are presented. The models of the surface currents satisfying either boundary condition are shown to simplify considerably when the surface layer is thin. A model consisting of several layers, with piecewise-constant α, may be used to find an approximate solution for a force-free flux tube with an arbitrarily specified current profile.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1994

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References

REFERENCES

Bray, R. J., Cram, L. E., Durrant, C. J. & Loughhead, R. E. 1991 Plasma Loops in the Solar Corona. Cambridge University Press.CrossRefGoogle Scholar
Browning, P. K., Sakurai, T. & Prieset, E. R. 1986 Astron. Astrophys. 158, 217.Google Scholar
Chiuderi, C., Einaudi, G., Ma, S. S. & Van Hoven, G. 1980 J. Plasma Phys. 24, 39.Google Scholar
Gold, T. & Hoyle, F. 1960 Mon. Not. R. Astron. Soc. 120, 89.CrossRefGoogle Scholar
Heyvaerts, J. & Priest, E. R. 1984 Astron. Astrophys. 137, 63.Google Scholar
Königl, A. & Choudhuri, A. R. 1985 Astrophys. J. 289, 173.CrossRefGoogle Scholar
Low, B. C. 1985 Solar Phys. 100, 309.CrossRefGoogle Scholar
Low, B. C. 1993 Astrophys. J. 409, 798.CrossRefGoogle Scholar
Lüst, R. & Schlüter, A. 1954 Z. Astrophys. 34, 263.Google Scholar
Norman, C. A. & Heyvaerts, J. 1983 Astron. Astrophys. 124, LI.Google Scholar
Parker, E. N. 1979 Cosmical Magnetic Fields. OxfordUniversity Press.Google Scholar
Priest, E. R. 1982 Solar Magnetohydrodynamics. Reidel.Google Scholar
Taylor, J. B. 1974 Phys. Rev. Lett. 33, 1139.Google Scholar
Taylor, J. B. 1986 Rev. Mod. Phys. 58, 741.Google Scholar