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Solar Physics

, Volume 111, Issue 2, pp 279–285 | Cite as

10.7-cm Solar radio flux and the magnetic complexity of active regions

  • Robert M. Wilson
  • Douglas Rabin
  • Ronald L. Moore
Article

Abstract

During sunspot cycles 20 and 21, the maximum in smoothed 10.7-cm solar radio flux occurred about 1.5 yr after the maximum smoothed sunspot number, whereas during cycles 18 and 19 no lag was observed. Thus, although 10.7-cm radio flux and Zürich suspot number are highly correlated, they are not interchangeable, especially near solar maximum. The 10.7-cm flux more closely follows the number of sunspots visible on the solar disk, while the Zürich sunspot number more closely follows the number of sunspot groups. The number of sunspots in an active region is one measure of the complexity of the magnetic structure of the region, and the coincidence in the maxima of radio flux and number of sunspots apparently reflects higher radio emission from active regions of greater magnetic complexity. The presence of a lag between sunspot-number maximum and radio-flux maximum in some cycles but not in others argues that some aspect of the average magnetic complexity near solar maximum must vary from cycle to cycle. A speculative possibility is that the radio-flux lag discriminates between long-period and short-period cycles, being another indicator that the solar cycle switches between long-period and short-period modes.

Keywords

Active Region Solar Cycle Magnetic Structure Radio Emission Sunspot Number 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. Bray, R. J. and Loughhead, R. E.: 1964, Sunspots, John Wiley and Sons, Inc., New York.Google Scholar
  2. Bumba, V. and Howard, R.: 1965, Astrophys. J. 141, 1502.Google Scholar
  3. Covington, A. E.: 1954, J. Geophys. Res. 59, 163.Google Scholar
  4. Covington, A. E.: 1959, in R. N. Bracewell (ed.), Paris Symposium on Radio Astronomy, Stanford University Press, Stanford, California, p. 159.Google Scholar
  5. Covington, A. E.: 1969, J. Roy. Astron. Soc. Can. 63, 125.Google Scholar
  6. Covington, A. E. and Harvey, G. A.: 1960, Astrophys. J. 132, 435.Google Scholar
  7. de Jager, C.: 1959, in S. Flügge (ed.), Encyclopedia of Physics, Vol. LII, Astrophysics III: The Solar System, Springer-Verlag, Berlin, p. 80.Google Scholar
  8. Dodson, H. W., Hedeman, E. R., and Mohler, O. C.: 1974, Rev. Geophys. Space Phys. 12, 329.Google Scholar
  9. Gaizauskas, V., Harvey, K. L., Harvey, J. W., and Zwaan, C.: 1983, Astrophys. J. 265, 1056.Google Scholar
  10. Gary, G. A., Moore, R. L., Hagyard, M. J., and Haisch, B. M: 1987, Astrophys. J. 314, 782.Google Scholar
  11. Howard, R.: 1977, in A. Bruzek and C. J. Durrant (eds.), Illustrated Glossary for Solar and Solar-Terrestrial Physics, D. Reidel Publ. Co., Dordrecht, Holland, p. 7.Google Scholar
  12. Howard, R., Gilman, P. A., and Gilman, P. I.: 1984, Astrophys. J. 283, 373.Google Scholar
  13. Kiepenheuer, K. O.: 1953, in G. P. Kuiper (ed.), The Sun, Vol. I, The Solar System, The University of Chicago Press, Chicago, p. 322.Google Scholar
  14. McIntosh, P. S.: 1981, in L. E. Cram and J. H. Thomas (eds.), The Physics of Sunspots, Sacramento Peak Observatory, Sunspot, New Mexico, p. 7.Google Scholar
  15. Moore, R. L. and Rabin, D.: 1985, Ann. Rev. Astron. Astrophys. 23, 239.Google Scholar
  16. Moore, R. L., Hurford, G. J., Jones, H. P., and Kane, S. R.: 1984, Astrophys. J. 276, 379.Google Scholar
  17. Rabin, D., Wilson, R. M., and Moore, R. L.: 1986, Geophys. Res. Letters 13, 352.Google Scholar
  18. Rust, D. M.: 1972, in P. S. McIntosh and M. Dryer (eds.), Solar Activity Observations and Predictions, Vol. 30, Progress in Astronautics and Aeronautics, MIT Press, Cambridge, Massachusetts, p. 33.Google Scholar
  19. Švestka, Z.: 1976, Solar Flares, Vol. 8, Geophysics and Astrophysics Monograph, D. Reidel Publ. Co., Dordrecht, Holland.Google Scholar
  20. Waldmeier, M.: 1961, The Sunspot-Activity in the Years 1610–1960, Schulthess and Co., Zürich.Google Scholar
  21. Wilson, R. M.: 1987a, Solar Phys. 108, 195.Google Scholar
  22. Wilson, R. M.: 1987b, J. Geophys. Res. (in press).Google Scholar

Copyright information

© D. Reidel Publishing Company 1987

Authors and Affiliations

  • Robert M. Wilson
    • 1
  • Douglas Rabin
    • 2
  • Ronald L. Moore
    • 1
  1. 1.Space Science Laboratory, NASA Marshall Space Flight CenterHuntsvilleUSA
  2. 2.National Solar Observatory, National Optical Astronomy ObservatoriesTucsonUSA

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