Solar Physics

, Volume 141, Issue 2, pp 235–251 | Cite as

Magnetoacoustic-gravity surface waves

II. Uniform Magnetic Field
  • Alan J. Miles
  • H. R. Allen
  • B. Roberts


The linearized theory for the parallel propagation of magnetoacoustic-gravity surface waves is developed and a dispersion relation obtained for the case of an isothermal interface of a uniform horizontal magnetic field residing above a field-free medium. The transcendental dispersion relation is solved numerically for a range of parameters and the resulting dispersion curves and corresponding eigenfunctions plotted. As in the case of a uniform Alfvén speed (Paper I), the existence of the fast and slow magnetoacoustic-gravity surface modes and the f-mode (modified by the presence of the uniform magnetic field) is determined by the relative temperatures of the two media either side of the interface. If the lower field-free region is cooler than the upper magnetic atmosphere only the slow magnetoacoustic-gravity surface mode may propagate. In addition to these three surface modes we find higher harmonic-type trapped modes. The existence of these modes also depends on the temperatures either side of the interface. They propagate only when both the field-free region is warmer than the magnetic field region and the Alfvén speed is greater than the corresponding sound speed in the magnetic atmosphere.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Abramowitz, M. and Stegun, I. A.: 1965, Handbook of Mathematical Functions, Dover Publ., New York.Google Scholar
  2. Adam, J. A.: 1975, Ph.D. Thesis, University of London.Google Scholar
  3. Adam, J. A.: 1977, Solar Phys. 52, 293.Google Scholar
  4. Evans, D. J. and Roberts, B.: 1990, Astrophys. J. 356, 704.Google Scholar
  5. Goedbloed, J. P.: 1971, Physica 53, 412.Google Scholar
  6. González, A. G. and Gratton, J.: 1991, Solar Phys. 134, 211.Google Scholar
  7. Kumar, P., Duvall, T. L., Jr., Harvey, J. W., Jefferies, S. M., Pomerantz, M. A., and Thompson, M. J.: 1991, Lecture Notes in Physics 367, 87.Google Scholar
  8. Lamb, H.: 1932, Hydrodynamics, Cambridge University Press, Cambridge, Chapter X.Google Scholar
  9. Miles, A. J. and Roberts, B.: 1989, Solar Phys. 119, 257.Google Scholar
  10. Miles, A. J. and Roberts, B.: 1991, in M. Dubois, F. Bely-Dubau, and D. Gresillon (eds.), Plasma Phenomena in the Solar Atmosphere, Cargèse, p. 77.Google Scholar
  11. Miles, A. J. and Roberts, B.: 1992, Solar Phys. 141, 205 (Paper I).Google Scholar
  12. Nye, A. H. and Thomas, J. H.: 1976a, Astrophys. J. 204, 573.Google Scholar
  13. Nye, A. H. and Thomas, J. H.: 1976b, Astrophys. J. 204, 582.Google Scholar
  14. Roberts, B.: 1981, Solar Phys. 69, 27.Google Scholar
  15. Roberts, B.: 1985, in E. R. Priest (ed.), Solar System Magnetic Fields, D. Reidel Publ. Co., Dordrecht, Holland, p. 37.Google Scholar
  16. Small, L. M. and Roberts, B.: 1984, in The Hydromagnetics of the Sun, ESA SP-220, p. 257.Google Scholar
  17. Wentzel, D. G.: 1979, Astrophys. J. 227, 319.Google Scholar
  18. Woodard, M. F. and Libbrecht, K. G.: 1991, Astrophys. J. 374, L61.Google Scholar

Copyright information

© Kluwer Academic Publishers 1992

Authors and Affiliations

  • Alan J. Miles
    • 1
  • H. R. Allen
    • 1
  • B. Roberts
    • 1
  1. 1.Department of Mathematical and Computational SciencesUniversity of St. AndrewsSt. Andrews, FifeScotland

Personalised recommendations