Solar Physics

, Volume 143, Issue 2, pp 301–316 | Cite as

A new investigation of microbursts at meter-decameter wavelengths

  • K. R. Subramanian
  • N. Gopalswamy
  • Ch. V. Sastry


We report on a new investigation of microbursts at meter-decameter wavelengths observed using the Broad Band Array at Gauribidanur Radio Observatory. This is an independent set of observations of microbursts: previous observations had been obtained only by the Clark Lake multifrequency radioheliograph. We confirm several properties of microbursts reported earlier. In addition, we have studied some new properties of microbursts such as time profile characteristics, flux density and energy spectra for comparison with the corresponding properties of normal type III bursts. The present study supports the idea that the microbursts and the normal type III bursts are generated by electron beams of similar characteristics. We interpret the low brightness temperature of microbursts as follows: plasma waves generated by the electron beams through beam-plasma instability are quickly isotropized as they scatter on the density fluctuations in the corona. The resulting low levels of plasma waves are converted into transverse radiation of low brightness temperature. One important consequence of the isotropization is that the second harmonic plasma emission dominates the fundamental and hence the microbursts are expected to be predominantly a harmonic plasma emission.


Electron Beam Energy Spectrum Flux Density Broad Band Time Profile 
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  1. Alvarez, H. and Haddock, F. T.: 1973,Solar Phys. 29, 197.Google Scholar
  2. Aubier, M. and Boischot, A.: 1972,Astron. Astrophys. 19, 343.Google Scholar
  3. Aubier, M., Leblanc, Y., and Boischot, A.: 1971,Astron. Astrophys. 12, 435.Google Scholar
  4. Barrow, C. H. and Achong, A.: 1975,Solar Phys. 45,459.Google Scholar
  5. Bastian, T.: 1991,Astrophys. J. 370, L49.Google Scholar
  6. Elgaroy, O. and Lyngstad, E.: 1973,Astron. Astrophys. 16, 1.Google Scholar
  7. Goldman, M. V. and DuBois, D. F.: 1982,Phys. Fluids 25, 1062.Google Scholar
  8. Gopalswamy, N.: 1990,Solar Phys. 126, 367.Google Scholar
  9. Gopalswamy, N.: 1993,Astrophys. J. (in press).Google Scholar
  10. Gopalswamy, N. and Kundu, M. R.: 1989,Solar Phys. 122, 145.Google Scholar
  11. Gopalswamy, N., Kundu, M. R., and Szabo, A.: 1987,Solar Phys. 108, 333.Google Scholar
  12. Haddock, F. T. and Graedal, T. E.: 1970,Astrophys. J. 160, 293.Google Scholar
  13. Kellerman, K. I., Pauliny-Toth, I. I. K., and Williams, P. J. S.: 1969,Astrophys. J. 157, 1.Google Scholar
  14. Kundu, M. R., Erickson, W. C., Gergely, T. E., Mahoney, M. J., and Turner, P. J.: 1983,Solar Phys. 83, 385.Google Scholar
  15. Kundu, M. R., Gergely, T. E., Szabo, A., Loiacono, R., and White, S. M.: 1986,Astrophys. J. 308, 436.Google Scholar
  16. Lin, R. P., Schwartz, R. A., Pelling, R. M., and Hurley, K. C.: 1981,Astrophys. J. 251, L109.Google Scholar
  17. Muschietti, L., Goldman, M. V., and Newman, D. L.: 1985,Solar Phys. 96, 181.Google Scholar
  18. Nishikawa, K. and Ryutov, D.: 1976,J. Phys. Soc. Japan 41, 1757.Google Scholar
  19. Subramanian, K. R. and Sastry, C. V.: 1988,J. Astrophys. Astron. 9, 125.Google Scholar
  20. Subramanian, K. R., Krishan, V., and Sastry, C. V.: 1981,Solar Phys. 70, 375.Google Scholar
  21. Subramanian, K. R., Gowda, G. N., Hameed, A. T. A., and Sastry, C. V.: 1986,Bull. Astron. Soc. India 14, 236.Google Scholar
  22. Suzuki, S. and Dulk, G. A.: 1985, in D. J. McLean and N. R. Labrum (eds.),Solar Radiophysics, Cambridge University Press, Cambridge, Ch. 12.Google Scholar
  23. Thejappa, G., Gopalswamy, N., and Kundu, M. R.: 1990,Solar Phys. 127, 165.Google Scholar
  24. Weber, R. R.: 1969,Solar Phys. 8, 376.Google Scholar
  25. White, S. M., Kundu, M. R., and Szabo, A.: 1986,Solar Phys. 107, 135.Google Scholar
  26. Wild, J. P.: 1950,Australian J. Sci. Res. 34, 541.Google Scholar
  27. Yakovlev, O. I., Efimov, A. I., Razmanov, V. M., and Shtrykov, V.K.: 1980,Soviet Astron. 24, 454.Google Scholar
  28. Zaitsev, V. V. and Stepanov, A. V.: 1983,Solar Phys. 88, 297.Google Scholar

Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • K. R. Subramanian
    • 2
  • N. Gopalswamy
    • 1
  • Ch. V. Sastry
    • 2
  1. 1.Dept. of AstronomyUniversity of MarylandUSA
  2. 2.Indian Institute of AstrophysicsBangaloreIndia

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