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Alfvén surface waves along cylindrical annular streaming jets having a very dense fluid mantle pervaded by longitudinal magnetic fields

Published online by Cambridge University Press:  13 March 2009

Ahmed E. Radwan
Affiliation:
Department of Mathematics, Faculty of Science, Ain-Shams University, Abbassia, Cairo, Egypt

Abstract

The characteristics of Alfvén surface waves along a cylindrical annular streaming column with a solid core and surrounded by a tenuous medium, and pervaded by a longitudinal magnetic field are studied analytically and numerically. Both axisymmetric (m = 0) and non-axisymmetric (m ≠ 0) modes are found to be dispersive. The Alfvén-wave velocity decreases with increasing magnetic field. Under an infinitesimal perturbation, the motion of the system is laminar and stable for all values of m for all short and long wavelengths if the unperturbed state is non-streaming. If the system is streaming, there will be unstable domains not only for m = 0 but also for m ≠ = 0 owing to the strong destabilizing influence of the streaming. However, this instability can be suppressed completely if the magnetic field is sufficiently high that the Alfvén-wave velocity is greater than the streaming velocity. The thicker the solid core the greater is its stabilizing influence for m = ±1, and vice versa for m = 0. A longitudinal field imparts a degree of rigidity to the conducting fluid, so it always has a strong stabilizing influence.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1992

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References

Abramowitz, M. & Stegun, I. A. 1965 Handbook of Mathematical Functions. Dover.Google Scholar
Chandrasekhar, S. 1981 Hydrodynamic and Hydromagnetic Stability. Dover.Google Scholar
Gradshteyn, I. S. & Ryzhik, I. M. 1980 Tables of Integrals, Series and Products. Academic.Google Scholar
Hasegawa, A. & Chen, L. 1976 Phys. Fluids 19, 1924.Google Scholar
Ionson, J. A. 1978 Astrophys. J. 226, 650.Google Scholar
Kendall, J. M. 1986 Phys. Fluids 29, 2086.Google Scholar
Monin, A. S. 1986 Soviet Phys. Usp. 29, 843.Google Scholar
Radwan, A. E. 1987 Nuovo Cini. 9, 1233.Google Scholar
Radwan, A. E. 1989 J. Phijs. Soc. Japan 58, 1225.Google Scholar
Radwan, A. E. & Callebaut, D. 1986 Proc. Belg. Phys. Soc, p. 21.Google Scholar
Uberoi, C. & Somasundaram, K. 1980 Plasma Phys. 22, 747.Google Scholar