Abstract:
The compressible magnetohydrodynamic Kelvin-Helmholtz instability occurs in two varieties, one that can be called incompressible as it exists in the limit of vanishing compressibility (primary instability), while the other exists only when compressibility is included in the model (secondary instability). In previous work we developed techniques to investigate the stability of a surface of discontinuity between two different uniform flows. Our treatment includes arbitrary jumps of the velocity and magnetic fields as well as of density and temperature, with no restriction on the wave vector of the modes. Then it allows stability analyses of complex configurations not previously studied in detail. Here we apply our methods to investigate the stability of various typical situations occurring at different regions of the front side, and the near flanks of the magnetopause. The physical conditions of the vector and scalar fields that characterize the equilibrium interface at the positions considered are obtained both from experimental data and from results of simulation codes of the magnetosheath available in the literature. We give particular attention to the compressible modes in configurations in which the incompressible modes are stabilized by the magnetic shear. For configurations of the front of the magnetopause, which have small relative velocities, we find that the incompressible MHD model gives reliable estimates of their stability, and compressibility effects do not introduce significant changes. However, at the flanks of the magnetopause the occurrence of the secondary instability and the shift of the boundary of the primary instability play an important role. Consequently, configurations that are stable if compressibility is neglected turn out to be unstable when it is considered and the stability properties are quite sensitive on the values of the parameters. Then compressibility should be taken into account when assessing the stability properties of these configurations, since the estimates based on incompressible MHD may be misleading. A careful analysis is required in each case, since no simple rule of thumb can be given.
Registro:
| Documento: |
Artículo
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| Título: | Compressible Kelvin-Helmholtz instability at the terrestrial magnetopause |
| Autor: | González, A.G.; Gratton, J.; Gratton, F.T.; Farrugia, C.J. |
| Filiación: | Inst. de Física Arroyo Seco, Univ. Nac. Ctro. Prov. Buenos Aires, Pinto 399, 7000 Tandil, Buenos Aires, Argentina
Institute de Fisica del Plasma, Fac. de Ciencias Exactas y Naturales, Ciudad Universitaria, 1428 Buenos Aires, Argentina
Space Science Center, University of New Hampshire, Durham, NH, United States
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| Año: | 2002
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| Volumen: | 32
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| Número: | 4
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| Página de inicio: | 945
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| Página de fin: | 957
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| DOI: |
http://dx.doi.org/10.1590/S0103-97332002000500021 |
| Título revista: | Brazilian Journal of Physics
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| Título revista abreviado: | Braz. J. Phys.
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| ISSN: | 01039733
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| PDF: | https://bibliotecadigital.exactas.uba.ar/download/paper/paper_01039733_v32_n4_p945_Gonzalez.pdf |
| Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_01039733_v32_n4_p945_Gonzalez |
Referencias:
- Kivelson, M.G., Chen, S.H., The magnetopause: Surface waves and instabilities and their possible dynamic consequences (1995) Geophys. Mon. Ser., 90, p. 257. , AGU Monograph 90, Physics of Magnetopause, edited by P. Song, B. U. O. Sonnerup and M. F. Thomsen., AGU, Washington, DC
- Miura, A., Kelvin-Helmholtz instability at the magnetopause: Computer 'simulations (1995) Geophys. Mon. Ser., 90, p. 285. , AGU Monograph 90, Physics of Magnetopause, edited by P. Song, B. U. O. Sonnerup, and M. F. Thomsen. AGU, Washington, DC
- Farrugia, C.J., Gratton, F.T., Torbert, R.B., Viscous-type processes in the solar wind-magnetosphere interaction (2001) Space Science Review, 95 (1-2), p. 443. , Special volume Challenge to Long-Standing Unsolved Space Physics Problems in the 20th Century
- Duhau, S., Gratton, J., Kelvin-Helmholtz instability of anisotropic plasma in a magnetic field (1975) J. Plasma Phys., 13, p. 451
- Gratton, F., Gratton, J., González, A.G., Convective instability of internal modes in accelerated compressible plasmas (1988) Plasma Phys. Controlled Fusion, 30, p. 435
- Newcomb, W.A., Compressibility effects on instability growth rates (1983) Phys. Fluids, 26, p. 3246
- Kivelson, M.G., Southwood, D.J., Coupling of global magnetospheric MHD eigenmodes to field line resonances (1986) J. Geophys. Res., 91, p. 4345
- Kivelson, M.G., Pu, Z.-Y., The Kelvin-Helmholtz instability on the magnetopause (1984) Planet. Space. Sci., 32, p. 1335
- Gonzalez, A.G., Gratton, J., The Kelvin-Helmholtz instability in compressible plasmas (1998) Proc. VIII Latin-American Workshop on Plasma Physics, 1, p. 23. , Review papers. Tandil, Argentina
- Miura, A., Pritchett P, P.L., Nonlocal stability analysis of the MHD Kelvin-Helmholtz instability in a compressible plasma (1982) J. Geophys. Res., 87, p. 7431
- Farrugia, C.J., Gratton, F.T., Bender, L., Quinn, J.M., Torbert, R.B., Erkaev, N.V., Biernat, H.K., Recent work on the Kelvin-Helmholtz instability at the dayside magnetopause and boundary layer (1998) Polar Cap Boundary Phenomena, p. 1. , edited by J. Moen et al., Kluwer Academic Publishers, Netherlands
- Gonzalez, A.G., Gratton, J., The Kelvin-Helmholtz instability in a compressible plasma: The role of the orientation of the magnetic field with respect to the flow (1994) J. Plasma Phys., 51, p. 43
- González, A.G., Gratton, J., The role of a density jump in the Kelvin-Helmholtz instability of a compressible plasma (1994) J. Plasma Phys., 52, p. 233
- González, A.G., Gratton, J., González, M., The Kelvin-Helmholtz instability in compressible plasmas with magnetic field shear (2001) Proc. IX LAWPP, AIP Conf. Proc., 568, p. 47
- Chandrasekhar, S., (1961) Hydrodynamic and Hydromagnetic Stability, , Oxford Univ. Press
- Axford, W.I., (1960) Quart. J. Mech. Appl. Math., 13, p. 314
- Axford, W.I., (1962) Can. J. Phys., 40, p. 654
- Southwood, D.J., The hydrodynamic stability of the magnetospheric boundary (1968) Planet. Space Sci., 16, p. 587
- Miura, A., Dependence of the magnetopause Kelvin-Helmholtz instability on the orientation of the magnetosheath magnetic field (1995) Geophys. Res. Lett., 22, p. 2993
- Farrugia, C.J., Gratton, F.T., Bender, L., Biernat, H.K., Erkaev, N.V., Quinn, J.M., Torbert, R.B., Dennisenko, V., Charts of joint Kelvin-Helmholtz and Rayleigh-Taylor instabilities at the dayside magnetopause for strongly northward interplanetary magnetic field (1998) J. Geophys. Res., 103, p. 6703
- Contín, J.E., Gratton, F.T., Farrugia, C.J., A study of Kelvin-Helmholtz modes for hyperbolic tangent field profiles applied to the dayside magnetopause (2001) Fluidos 2001, , edited by J. C. Ferreri. ISBN 927-20148-0-9
- Contín, J.E., (1999) Inestabilidades de Láminas de Corriente con Flujos de Plasma y Aplicaciones a la Magnetopausa Diurna, , Ph. D. Thesis, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires
- Erkaev, N.V., Results of the investigation of MHD flow around the magnetosphere (1988) Geomagn. Aeron., 28, p. 455
- Farrugia, C.J., Gratton, F.T., Contin, J., Cocheci, C.C., Arnoldy, R.L., Ogilvie, K.W., Lepping, R.P., Rostoker, G., Coordinated wind, interball/tail, and ground observations of Kelvin-Helmholtz waves at the near-tail, equatorial magnetopause at dusk: January 11, 1997 (2000) J. Geophys. Res. A4, 105, p. 7639
Citas:
---------- APA ----------
González, A.G., Gratton, J., Gratton, F.T. & Farrugia, C.J.
(2002)
. Compressible Kelvin-Helmholtz instability at the terrestrial magnetopause. Brazilian Journal of Physics, 32(4), 945-957.
http://dx.doi.org/10.1590/S0103-97332002000500021---------- CHICAGO ----------
González, A.G., Gratton, J., Gratton, F.T., Farrugia, C.J.
"Compressible Kelvin-Helmholtz instability at the terrestrial magnetopause"
. Brazilian Journal of Physics 32, no. 4
(2002) : 945-957.
http://dx.doi.org/10.1590/S0103-97332002000500021---------- MLA ----------
González, A.G., Gratton, J., Gratton, F.T., Farrugia, C.J.
"Compressible Kelvin-Helmholtz instability at the terrestrial magnetopause"
. Brazilian Journal of Physics, vol. 32, no. 4, 2002, pp. 945-957.
http://dx.doi.org/10.1590/S0103-97332002000500021---------- VANCOUVER ----------
González, A.G., Gratton, J., Gratton, F.T., Farrugia, C.J. Compressible Kelvin-Helmholtz instability at the terrestrial magnetopause. Braz. J. Phys. 2002;32(4):945-957.
http://dx.doi.org/10.1590/S0103-97332002000500021