Abstract
We show that the observed modulation of some coronal microwave, X-ray and Type III emission into pulses of 10 sec intervals is a consequence of the stimulation of electron cyclotron waves propagated in the whistler mode in dipole-like bipolar regions of dimension ≈ 0.2 R ⊙. Assuming that a power law spectrum of ≥ 10 keV electrons with a slope similar to solar flare protons can be trapped in a bipolar region, we show that whistlers can be generated by pitch angle instability. The resultant ≈ 10 sec bounce motion of whistler wave trains leads to enhanced, modulated emission in microwave and X-ray frequencies by pitch angle scattering of MeV electrons, and to modulated Type III emission by scattering with coherent plasma waves. A direct prediction of the theory is the existence of sympathetic pulsations at two sources a fraction of a solar radius apart. A second test of the theory is that modulated Type III emission should show strong polarization.
Similar content being viewed by others
References
Anderson, K. A. and Lin, P. R.: 1966, Phys. Rev. Letters 16, 1121.
Bryant, D. A., Cline, T. L., Desai, U. D., and McDonald, F. B.: 1965, Astrophys. J. 141, 478.
Cornwall, J. M.: 1964, J. Geophys. Res. 70, 61.
Ginzburg, V. L. and Zhelesznyakov, V. V.: 1959, Paris Symposium on Radio Astronomy, Stanford Univ. Press, p. 574.
Janssens, T. J. and White, K.: 1970, Solar Phys. 11, 299.
Kai, K.: 1965, Publ. Astron. Soc. Japan 17, 294 and 309.
Kennel, C. F.: 1966, Phys. Fluids 9, 2190.
Komesaroff, M.: 1958, Australian J. Phys. 11, 201.
Krishnamurti, M., Sastry, G., and Rao, T.: 1965, Australian J. Phys. 18, 473.
Newkirk, G.: 1961, Astrophys. J. 133, 983.
Newkirk, G.: 1967, Am. Rev. Astron. Astrophys. 5, 256.
Parks, G. K. and Winckler, J. R.: 1969, Astrophys. J. 155, L117.
Petschek, H. E.: 1963, Symposium on Physics of Solar Flares, Goddard Space Flight Center, p. 425.
Rao, U. V. G.: 1965, Australian J. Phys. 18, 283.
Roberts, C. S. and Buchsbaum, S. J.: 1964, Phys. Rev. 135, 381.
Saito, K. and Billings, D. E.: 1964, Astrophys. J. 140, 760.
Schwinger, J.: 1949, Phys. Rev. 75, 1912.
Sitenko, A. G.: 1967, Electromagnetic Fluctuations in Plasma, Academic Press.
Steward, R. T.: 1966, Australian J. Phys. 18, 283.
Stix, T. H.: 1962, Theory of Plasma Waves, Addison-Wesley.
Takakura, T.: 1967, Solar Phys. 1, 304.
Terashima, Y. and Yajima, N.: 1963, Progr. Theoret. Phys. 30, 443.
Thorne, R. M. and Kennel, C. F.: 1967, J. Geophys. Res. 72, 857.
Van Allen, J. A. and Krimigis, S. M.: 1965, J. Geophys. Res. 70, 5737.
Wild, J. P., Roberts, J. A., and Murray, J. D.: 1954, Nature 173, 532.
Wild, J. P., Smerd, S. F., and Weiss, A. A.: 1963, Ann. Rev. Astron. Astrophys. p. 291.
Wild, J. P.: 1969, Solar Phys. 9, 260.
Author information
Authors and Affiliations
Additional information
This work was conducted under U.S. Air Force Space and Missile Systems Organization (SAMSO) Contract No. F04701-69-C-0066.
Rights and permissions
About this article
Cite this article
Chiu, Y.T. Theory of solar radio pulsation. Sol Phys 13, 420–443 (1970). https://doi.org/10.1007/BF00153561
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00153561