Abstract
We review high-spatial-resolution observations of the Sun which reflect on the role of mode coupling in the solar corona, and present a number of new observations. We show that typically polarization inversion is seen at 5 GHz in active region sources near the solar limb, but not at 1.5 GHz. Although this is apparently in contradiction to the simplest form of mode coupling theory, in fact it remains consistent with current models for the active region emission. Microwave bursts show no strong evidence for polarization inversion. We discuss bipolar noise storm continuum emission in some detail, utilizing recent VLA observations at 327 MHz. We show that bipolar sources are common at 327 MHz. Further, the trailing component of the bipole is frequently stronger than the leading component, in apparent conflict with the ‘leading-spot’ hypothesis. The observations indicate that at 327 MHz mode coupling is apparently strong at all mode-coupling layers in the solar corona. The 327 MHz observations require a much weaker magnetic field strength in the solar corona to explain this result than did earlier lower-frequency observations: maximum fields are 0.2 G. This is a much weaker field than is consistent with current coronal models.
Similar content being viewed by others
References
Abramov-Maksimov, V. E. and Gelfreikh, G. B.: 1983, Soviet Astron. Letters 9, 132.
Alissandrakis, C. E.: 1986, Solar Phys. 104, 207.
Alissandrakis, C. E. and Kundu, M. R.: 1984, Astron. Astrophys. 139, 271.
Alissandrakis, C. E. and Preka-Papadema, P.: 1984, Astron. Astrophys. 139, 507.
Bandiera, R.: 1982, Astron. Astrophys. 112, 52.
Bastian T. S.: 1987, Ph. D. Thesis, University of Colorado, unpublished.
Benz, A. O. and Wentzel, D. G.: 1981, Astron. Astrophys. 94, 100.
Benz, A. O., Urbarz, H., and Zlobec, P.: 1979, Astron. Astrophys. 79, 216.
Cohen, M. H.: 1960, Astrophys. J. 131, 664.
Dulk, G. A. and Gary, D. E.: 1983, Astron. Astrophys. 124, 103.
Elgaroy, O.: 1977, Solar Noise Storms, Pergamon Press, Oxford.
Ginzburg, V. L. and Zheleznyakov, V. V.: 1961, Soviet Astron. 5, 1.
Gopalswamy, N., White, S. M., and Kundu, M. R.: 1991, Astrophys. J. 379, 366.
Güdel, M. and Benz, A. O.: 1988, Astron. Astrophys. Suppl. Ser. 75, 243.
Habal, S. R., Ellman, N. E., and Gonzalez, R.: 1989, Astrophys. J. 342, 594.
Hewitt, R. G. and Melrose, D. B.: 1985, Solar Phys. 96, 157.
Hoeksema, J. T. and Scherrer, P. H.: 1986, Solar Phys. 105, 205.
Hoyng, P., Marsh, K. A., Zirin, H., and Dennis, B. R.: 1983, Astrophys. J. 268, 865.
Kai, K.: 1970, Solar Phys. 11, 456.
Kai, K. and Sheridan, K. V.: 1974, Solar Phys. 35, 181.
Kai, K., Melrose, D. B., and Suzuki, S.: 1985, in D. J. MacLean and N. R. Labrum (eds.), Solar Radiophysics, Cambridge University Press, Cambridge, p. 415.
Kakinuma, T. and Swarup, G.: 1962, Astrophys. J. 136, 975.
Kundu, M. R.: 1959, Ann. Astrophys. 22, 1.
Kundu, M. R. and Alissandrakis, C. E.: 1984, Solar Phys. 94, 249.
Kundu, M. R., Schmahl, E. J., and Velusamy, T.: 1982, Astrophys. J. 253, 963.
Kundu, M. R., Alissandrakis, C. E., Bregman, J. D., and Hin, A.: 1977, Astrophys. J. 213, 278.
Labrum, N. R. and Stewart, R. T.: 1970, Proc. Astron. Soc. Australia 1, 316.
Lang, K. R. and Willson, R. F.: 1987, Astrophys. J. 319, 514.
Lang, K. R. and Willson, R. F.: 1989, Astrophys. J. 344, L73.
Lang, K. R., Willson, R. F., and Trottet, G.: 1988, Astron. Astrophys. 199, 325.
Marsh, K. A., Hurford, G. J., Zirin, H., Dulk, G. A., Dennis, B. R., Frost, K. J., and Orwig, L. E.: 1981, Astrophys. J. 251, 797.
McLean, D. J. and Sheridan, K. V.: 1972, Solar Phys. 26, 176.
Melozzi, M., Kundu, M. R., and Shevgaonkar, R. K.: 1985, Solar Phys. 97, 345.
Melrose, D. B.: 1973, Proc. Astron. Australia 2, 208.
Melrose, D. B.: 1974a, Australian J. Phys. 27, 31.
Melrose, D. B.: 1974b, Australian J. Phys. 27, 43.
Melrose, D. B.: 1980a, Plasma Astrophysics, Gordon and Breach, New York.
Melrose, D. B.: 1980b, Solar Phys. 67, 357.
Peterova, N. G. and Akhmedov, S. B.: 1974, Soviet Astron. 17, 768.
Piddington, J. H. and Minnett, H. C.: 1951, Australian J. Sci. Res. A4, 131.
Preka-Papadema, P. and Alissandrakis, C. E.: 1988, Astron. Astrophys. 191, 365.
Ramaty, R.: 1969, Astrophys. J. 158, 753.
Sheridan, K. V., McLean, D. J., and Smerd, S. F.: 1973, Astrophys. Letters 15, 139.
Shevgaonkar, R. K. and Kundu, M. R.: 1985, Astrophys. J. 292, 733.
Shevgaonkar, R. K., Kundu, M. R., and Jackson, P. D.: 1988, Astrophys. J. 329, 982.
Spicer, S. D., Benz, A. O., and Huba, J. D.: 1981, Astron. Astrophys. 105, 221.
Stewart, R. T.: 1985, Solar Phys. 96, 381.
Stewart, R. T.: 1987, Solar Phys. 109, 139.
Suzuki, S.: 1961, Ann. Tokyo Astron. Obs. Ser. 2, 75.
Suzuki, S.: 1978, Solar Phys. 57, 415.
Suzuki, S. and Sheridan, K. V.: 1978, Radiophys. Quant. Electron. 20, 989.
Suzuki, S. and Sheridan, K. V.: 1980, Proc. Astron. Soc. Australia 4, 56.
Tanaka, H. and Kakinuma, T.: 1959, in R. N. Bracewell (ed.), Paris Symposium on Radio Astronomy, Stanford University Press, Stanford, p. 215.
Thejappa, G. and Kundu, M. R.: 1991, Solar Phys. 132, 155.
Wentzel, D. G.: 1986, Solar Phys. 103, 141.
White, S. M., Kundu, M. R., and Gopalswamy, N.: 1991a, Astrophys. J. (in press).
White, S. M., Kundu, M. R., and Gopalswamy, N.: 1991b, Astrophys. J. 366, L43.
Willson, R. F.: 1984, Solar Phys. 92, 189.
Willson, R. F.: 1985, Astrophys. J. 298, 911.
Willson, R. F., Lang, K. R., and Liggett, M.: 1990, Astrophys. J. 350, 856.
Willson, R. F., Klein, K. L., Kerdraon, A., Lang, K. R., and Trottet, G.: 1990, Astrophys. J. 357, 662.
Zheleznyakov, V. V.: 1962, Soviet Astron. AJ 6, 3.
Zheleznyakov, V. V.: 1977, Electromagnetic Waves in Cosmic Plasma: Generation and Propagation, Nauka, Moscow.
Zheleznyakov, V. V. and Zlotnik, E. Y.: 1964, Soviet Astron. 7, 485.
Zheleznyakov, V. V. and Zlotnik, E. Y.: 1978, Radiophys. Quant. Electron. 20, 997.
Zheleznyakov, V. V. and Zlotnik, E. Y.: 1988, Soviet Astron. Letters 14, 73.
Zheleznyakov, V. V., Kocharovskii, V. V., and Kocharovskii, V. V.: 1984, Soviet Phys. Usp. 26, 877.
Author information
Authors and Affiliations
Additional information
On leave from the Indian Institute for Astrophysics, Bangalore, India.
Rights and permissions
About this article
Cite this article
White, S.M., Thejappa, G. & Kundu, M.R. Observations of mode coupling in the solar corona and bipolar noise storms. Sol Phys 138, 163–187 (1992). https://doi.org/10.1007/BF00146202
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00146202