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Solar Physics

, Volume 131, Issue 1, pp 53–68 | Cite as

Magnetic flux transport of decaying active regions and enhanced magnetic network

  • Haimin Wang
  • Harold Zirin
  • Guoxiang Ai
Article

Abstract

Several series of coordinated observations on decaying active regions and enhanced magnetic network regions have been carried out jointly at Big Bear Solar Observatory (BBSO) and Huairou Solar Observing Station of the Bejing Astronomical Observatory in China. The evolution of magnetic fields in several regions was followed closely for 3 to 7 days. The transport of magnetic flux from the remnants of decayed active regions was studied. Three related topics are included in this paper. (1) We studied the evolution and lifetime of the magnetic network which defines the boundaries of supergranules. The results are consistent with our earlier studies: network cells have an average lifetime of about 70 hours; 68% of new cells appeared by growing from a single network magnetic element; 50% of decaying cells disappeared by contracting to a network element. (2) We studied the magnetic flux transport in an enhanced network region in detail, and found the diffusion rate to be negative, i.e., there was more flux moving towards the decayed active region than away from it. We found several other cases where the magnetic diffusion rate does not agree with Leighton's model. The slow diffusion rate is likely due to the fact that the average velocity of larger magnetic elements, which carry most of the magnetic flux, is less than 0.1 km s−1; their average lifetime is longer than 100 hours. (3) We briefly described some properties of Moving Magnetic Features (MMFs) around a sunspot (detailed discussion on MMFs will be presented in a separate paper). In this particular case, the MMFs did not carry net flux away from the central spot. Instead, the polarities of MMFs were essentially mixed so that outflowing positive and negative fluxes were roughly balanced. During the 3-day period, there was almost no net flux accumulation to form a moat. The cancellation of MMFs of opposite polarities at the boundary of the super-penumbra caused quite a few surges and Hα brightenings.

Keywords

Network Region Magnetic Flux Diffusion Rate Astronomical Observatory Average Lifetime 
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. Duvall, T. L.: 1980, Solar Phys. 66, 213.Google Scholar
  2. Harvey, J. and Harvey, K.: 1973, Solar Phys. 63, 105.Google Scholar
  3. Janssens, T. J.: 1970, Solar Phys. 11, 222.Google Scholar
  4. Leighton, R. B.: 1969, Astrophys. J. 156, 1.Google Scholar
  5. Leighton, R. B., Noyes, R. W., and Simon, G. W.: 1962, Astrophys. J. 135, 474.Google Scholar
  6. Livi, S. H. B., Wang, J., and Martin, S. F.: 1985, Australian J. Phys. 38, 855.Google Scholar
  7. Livi, S. H. B., Martin, S. F., Wang, H., and Ai, G.: 1989, Solar Phys. 121, 197.Google Scholar
  8. Martin, S. F.: 1990, BBSO Preprint, 0311.Google Scholar
  9. Martin, S. F. and Kong, F.: 1990, in preparation.Google Scholar
  10. Martin, S. F., Livi, S. H. B., and Wang, J.: 1985, Australian J. Phys. 38, 929.Google Scholar
  11. Mosher, J. M.: 1977, Ph. D. Thesis, California Institute of Technology.Google Scholar
  12. Schrijver, C. J.: 1989, Solar Phys. 122, 193.Google Scholar
  13. Simon, G. W. and Leighton, R. B.: 1964, Astrophys. J. 140, 1120.Google Scholar
  14. Smithson, R. C.: 1973, Solar Phys. 29, 365.Google Scholar
  15. Vrabec, D.: 1974, in G. R. Athay (ed.), Chromospheric Fine Structure, D. Reidel Publ. Co., Dordrecht, Holland, p. 201.Google Scholar
  16. Wang, H.: 1988, Solar Phys. 116, 1.Google Scholar
  17. Wang, H. and Zirin, H.: 1988, Solar Phys. 115, 205.Google Scholar
  18. Wang, H. and Zirin, H.: 1989, Solar Phys. 120, 1.Google Scholar
  19. Wang, H., Zirin, H., Patterson, A., Ai, G., and Zhang, H.: 1989, Astrophys. J. 343, 489.Google Scholar
  20. Worden, S. P. and Simon, G. W.: 1976, Solar Phys. 46, 73.Google Scholar

Copyright information

© Kluwer Academic Publishers 1991

Authors and Affiliations

  • Haimin Wang
    • 1
  • Harold Zirin
    • 1
  • Guoxiang Ai
    • 2
  1. 1.Big Bear Solar Observatory, California Institute of TechnologyPasadenaU.S.A.
  2. 2.Huairou Solar Observing Station, Bejing Astronomical ObservatoryBejingChina

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