Abstract
The magnetosonic modes of magnetic plasma structures in the solar atmosphere are considered taking into account steady flows of plasma in the internal and external media and using a slab geometry. The investigation brings nearer the theory of magnetosonic waveguides, in such structures as coronal loops and photospheric flux tubes, to realistic conditions of the solar atmosphere. The general dispersion relation for the magnetosonic modes of a magnetic slab in magnetic surroundings is derived, allowing for field-aligned steady flows in either region. It is shown that flows change both qualitatively and quantitatively the characteristics of magnetosonic modes. The flow may lead to the appearance of a new type of trapped mode, namelybackward waves. These waves are the usual slab modes propagating in the direction opposite to the internal flow, but advected with the flow. The disappearance of some modes due to the flow is also demonstrated.
The results are applied to coronal and photospheric magnetic structures. In coronal loops, the appearance of backward slow body waves or the disappearance of slow body waves, depending upon the direction of propagation, is possible if the flow speed exceeds the internal sound speed (≈ 300 km s−1). In photospheric tubes, the disappearance of fast surface and slow body waves may be caused by an external downdraught of about 3 km s−1.
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References
Aschwanden, M. J.: 1987,Solar Phys. 111, 113,
Cally, P. S.: 1986,Solar Phys. 108, 183.
Chakraborty, B. B.: 1968,Progress of Theoretical Phys. 40, 210.
Chandrasekhar, S.: 1961,Hydrodynamic and Hydromagnetic Stability, Clarendon Press, London.
Davila J. M.: 1985,Astrophys. J. 291, 328.
Edwin, P. M. and Roberts, B.: 1982,Solar Phys. 76, 239.
Edwin, P. M. and Roberts, B.: 1983,Solar Phys. 88, 179.
Ferrari, A., Trussoni, E., and Zaninetti, L.: 1981,Monthly Notices Roy. Astron. Soc. 196, 1051.
Goossens, M., Hollweg, J. V., and Sakurai, T.: 1992.Solar Phys. 138, 233.
Hollweg, J. V., Yang, G., Cadez, V. M., and Gakovic, B.: 1990,Astrophys. J. 349, 335.
Lee, L. C., Wang, S., Wei, C. Q., and Tsurutani, B. T.: 1988,J. Geophys. Res. 93, 7354.
McKenzie, J. F.: 1970,J. Geophys. Res. 75, 5331.
Nakariakov, V. M. and Oraevsky, V. N.: 1995,Solar Phys., in press.
Parker, E. N.: 1964,Astrophys. J. 139, 690.
Roberts, B.: 1981a,Solar Phys. 69, 27.
Roberts, B.: 1981b,Solar Phys. 69, 39.
Roberts, B., Edwin, P. M., and Benz, A. O.: 1984,Astrophys. J. 279, 857.
Ryutova, M. P.: 1988,Soviet Phys. JETF 67, 1594.
Satya Narayanan, A.: 1991,Plasma Phys. Control. Fusion 33, 333.
Satya Narayanan, A. and Somasundaram, K.: 1985,Astrophys. Space Sci. 109, 357.
Singh, A. P. and Talwar, S. P.: 1993,Solar Phys. 148, 27.
Singh, A. P. and Talwar, S. P.: 1994,Solar Phys. 149, 331.
Somasundaram, K. and Satya Narayanan, A.: 1987,Plasma Phys. Control. Fusion 29, 497.
Spruit, H. C.: 1982,Solar Phys. 75, 3.
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Nakariakov, V.M., Roberts, B. Magnetosonic waves in structured atmospheres with steady flows. Sol Phys 159, 213–228 (1995). https://doi.org/10.1007/BF00686530
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DOI: https://doi.org/10.1007/BF00686530