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Transequatorial loops interconnecting McMath regions 12472 and 12474

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Abstract

We discuss the life-story of a transequatorial loop system which interconnected the newly born active region McMath 12474 with the old region 12472. The loop system was probably born through reconnection accomplished 1.5 to 5 days after the birth of 12474 and the loops were observed in soft X-rays for at least 1.5 days. Transient ‘sharpenings’ of the interconnection and a striking brightening of the whole loop system for about 6 hr appear to be caused by magnetic field variations in the region 12474. A flare might have been related to the brightening, but only in an indirect way: the same emerging flux could have triggered the flare and at the same time strengthened the magnetic field at the foot-points of the loops. Electron temperature in the loop system, equal to 2.1 × 106 K in its quiet phase, increased to 3.1 × 106 K during the brightening. Electron density in the loop system was ≤ 1.3 × 109 cm−3 and it could be estimated to ∼7 × 108 cm−3 prior to the brightening. During the brightening the loops became twisted. There was no obvious effect whatsoever of the activity in 12474 upon the in erconnected old region. The final decay of the loop system reflected the decay of magnetic field in the region 12474.

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References

  1. Chase, R. C., Krieger, A. S., Švestka, Z., and Vaiana, G. S.: 1975,Space Res. 16 (in press).

  2. Cox, D. P. and Tucker, W. H.: 1969,Astrophys. J. 157, 1157.

  3. Culhane, J. L., Vesecky, J. F., and Phillips, K. J. H.: 1970,Solar Phys. 15, 394.

  4. Dodson, H. W.: 1975, private communication.

  5. Dodson, H. W. and Hedeman, E. R.: 1970,Solar Phys. 13, 401.

  6. Fritzová-Švestková, L., Chase, R. C., and Švestka, Z.: 1976,Solar Phys. 48, 275.

  7. Hirayama, T. and Endler, F.: 1975,Bull. Am. Astron. Soc. 7, 352 (abstract).

  8. Horan, D. M.: 1971,Solar Phys. 21, 188.

  9. Hudson, H. S.: 1973, in R. Ramaty and R. G. Stone (eds.),Symposium on High Energy Phenomena on the Sun, NASA-GSFC Preprint, p. 207.

  10. Kane, S. R. and Anderson, K. A.: 1970,Astrophys. J. 162, 1003.

  11. Lin, R. P. and Hudson, H. S.: 1971,Solar Phys. 17, 412.

  12. Milkey, R. W., Blocker, N. K., Chambers, W. H., Fehlan, P. E., Fuller, J. C., and Kunz, W. E.: 1971,Solar Phys. 20, 400.

  13. Piddington, J. H.: 1973,Solar Phys. 33, 363.

  14. Savage, B. D.: 1969,Astrophys. J. 156, 707.

  15. Spitzer, L.: 1962,Physics of Fully Ionized Gases, (2nd edition), Interscience Publ., New York-London.

  16. Sturrock, P. A.: 1973, in R. Ramaty and R. G. Stone (eds.),Symposium on High Energy Phenomena on the Sun, NASA-GSFC Preprint, p. 3.

  17. Švestka, Z.: 1976,Solar Flares, D. Reidel Publ. Company, Dordrecht, Holland.

  18. Uchida, Y. and Kaburaki, O.: 1974,Solar Phys. 35, 451.

  19. Vaiana, G. S., Krieger, A. S., Petrasso, R., Silk, J. K., and Timothy, A. F.: 1974, in L. Larmore and D. Crawford (eds.),Instrumentation in Astronomy-II, Seminar Proceedings, Soc. of Photo-Optical Instrumentation Engineers44, 185.

  20. Wentzel, D. G.: 1974,Solar Phys. 39, 129.

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Švestka, Z., Krieger, A.S., Chase, R.C. et al. Transequatorial loops interconnecting McMath regions 12472 and 12474. Sol Phys 52, 69–90 (1977). https://doi.org/10.1007/BF00935791

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Keywords

  • Magnetic Field
  • Flare
  • Active Region
  • Electron Temperature
  • Obvious Effect