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Purely growing electromagnetic modes in high-β plasmas

Published online by Cambridge University Press:  13 March 2009

G. S. Lakhina
Affiliation:
Physical Research Laboratory, Ahmedabad 380009, India
B. Buti
Affiliation:
Physical Research Laboratory, Ahmedabad 380009, India
Girija Nayar
Affiliation:
Physical Research Laboratory, Ahmedabad 380009, India

Abstract

Electromagnetic waves propagating transverse to an external magnetic field in a high-β (β being the ratio of the kinetic pressure to the magnetic pressure) plasma become unstable through purely growing modes when β∥e, (electron β parallel to the magnetic field) exceeds a certain minimum value β∥*. For J ≦ 2 (J being the distribution index), the region of instability consists of a single band of unstable wavenumbers k, whereas for J ≥ 3 more than one unstable wave number band may exist. The growth rates are largest for J = 0, and tend to decrease as J increases. The presence of hot ions increases the instability region by exciting a low-frequency instability. This instability gets excited at considerably lowered values of β‖e, and has growth rates of the order of ion cyclotron frequency. The effect of T‖i/T‖e and T‖e/T⊥e is destabilizing, whereas that of T⊥i/T⊥e is stabilizing.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1974

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References

REFERENCES

Brambilla, M. 1970M Plasma Phys. 12, 903.CrossRefGoogle Scholar
Buti, B. & Lakhina, G. S. 1971 J. Plasma Phys. 5, 467.CrossRefGoogle Scholar
Buti, B. 1973 Phys. Fluids. (To be published.)Google Scholar
Callen, J. D. & Guest, G. E. 1971 Phys. Fluids, 14, 1588.CrossRefGoogle Scholar
Davidson, R. C. & Wu, C. S. 1970 Phys. Fluids, 13, 1407.CrossRefGoogle Scholar
Dory, R. A., Guest, G. E. & Harris, E. G. 1965 Phys. Rev. Lett. 14, 131.CrossRefGoogle Scholar
Guest, G. E. & Dory, R. A. 1965 Phys. Fluids, 8, 1853.CrossRefGoogle Scholar
Hall, L. S., Heckrotte, W. & Kammash, T. 1965 Phys. Rev. 139, A 1117.CrossRefGoogle Scholar
Hamaski, S. 1968 Phys. Fluids, 11, 2724.CrossRefGoogle Scholar
Himmel, L. C. 1971 Phys. Fluids, 14, 1419.CrossRefGoogle Scholar
Lee, K. F. 1969 Phys. Rev. 181, 447.CrossRefGoogle Scholar
Lee, K. F. 1972 Phys. Rev. A 6, 355.CrossRefGoogle Scholar
Post, R. F. & Rosenblute, M. N. 1966Google Scholar
Phys. Fluids, 9, 730.Google Scholar
Rosenbluth, M. N. & Post, R. F. 1965 Phys. Fluids, 8, 547.CrossRefGoogle Scholar