Solar Physics

, Volume 88, Issue 1–2, pp 329–336

The reason for magnetospheric substorms and solar flares

  • Walter J. Heikkila


It has been proposed that magnetospheric substorms and solar flares are a result of the same mechanism. In our view this mechanism is connected with the escape, or attempted escape, of energized plasma from a region of closed magnetic field lines bounded by a magnetic bottle. In the case of the Earth, it must be plasma that is able to maintain a discrete auroral arc, and we propose that the cross-tail current connected to the arc is filamentary in nature to provide the field-aligned current sheet above the arc. A localized meander of such an intense current filament could be caused by a tearing instability in the neutral sheet. Such a meander will cause an inductive electric field opposing the current change everywhere. In trying to reduce the component of the induction electric field parallel to the magnetic field lines, the plasma must enhance the transverse or cross-tail component; this action leads to eruptive behavior, in agreement with tearing theories. This enhanced induction electric field will cause a discharge along the magnetic neutral line at the apex of the magnetic arches, constituting an impulsive acceleration of all charged particles originally near the neutral line. The products of this phase then undergo betatron acceleration for a second phase. This discharge eventually reduces the electric field along the neutral line, and thereafter the enclosed magnetic flux through the neutral line remains nearly constant. The result is a plasmoid that has definite identity; its buoyancy leads to its escape. The auroral breakup (and solar flare) is the complex plasma response to the changing electromagnetic field.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Akasofu, S.-I.: 1979, Solar Phys. 64, 333.Google Scholar
  2. Axford, W. I.: 1969, in D. J. Williams and G. Mead (eds.), Magnetospheric Physics, American Geophysical Union, p. 421.Google Scholar
  3. Baker, D. N., Hones, E. W., Jr., Payne, J. B., and Feldman, W. C.: 1981, Geophys. Res. Letters 8, 179.Google Scholar
  4. Birn, J. and Hones, E. W., Jr.: 1981, J. Geophys. Res. 86, 6802.Google Scholar
  5. Brown, J. C. and Smith, D. F.: 1980, Rep. Progr. Phys. 43, 129.Google Scholar
  6. Cragin, B. L. and Heikkila, W. J.: 1981, Rev. Geophys. Space Phys. 19, 223.Google Scholar
  7. Dungey, J. W.: 1953, Phil. Mag. 44, 725.Google Scholar
  8. Galeev, A. A.: 1979, Space Sci. Rev. 23, 411.Google Scholar
  9. Galeev, A. A.: 1982, in A. Nishida (ed.), Magnetospheric Tail Dynamics in Magnetospheric Plasma Physics, D. Reidel Publ. Co., Dordrecht, Holland.Google Scholar
  10. Galeev, A. A., Coroniti, F. V., and Ashour-Abdalla, M.: 1978, Geophys. Res. Letters 5, 707.Google Scholar
  11. Giovanelli, R. G.: 1948, Monthly Notices Roy. Astron. Soc. 108, 173.Google Scholar
  12. Gosling, J. T., Hildner, E., MacQueen, R. M., Monro, R. H., Poland, A. I., and Ross, C. L.: 1974, J. Geophys. Res. 79, 4581.Google Scholar
  13. Heikkila, W. J.: 1981, in S.-I. Akasofu and J. R. Kan (eds.), Physics of Auroral Arc Formation, Geophysical Monograph No. 25, American Geophysical Union, (University of Alaska, Chapman Conference, July 21–25, 1980).Google Scholar
  14. Heikkila, W. J.: 1982, Geophys. Res. Letters 9, 159.Google Scholar
  15. Heikkila, W. J. and Pellinen, R. J.: 1977, J. Geophys. Res. 82, 1610.Google Scholar
  16. Heikkila, W. J., Pellinen, R. J., Fälthammar, C.-G., and Block, L. P.: 1979, Planetary Space Sci. 27, 1383.Google Scholar
  17. Hones, E. W.: 1979, Space Sci. Rev. 23, 393.Google Scholar
  18. Hoyle, F.: 1949, Some Recent Researches in Solar Physics, Cambridge, p. 103.Google Scholar
  19. Hundhausen, A. J.: 1972, Coronal Expansion and Solar Wind, Springer-Verlag, New York.Google Scholar
  20. Kennel, C.: 1980, in Solar-System Space Physics in the 1980's: A Research Strategy, p. 55.Google Scholar
  21. Kirsch, E., Krimigis, S. M., Sarris, E. T., Lepping, R. P., and Armstrong, T. P.: 1977, Geophys. Res. Letters 4, 137.Google Scholar
  22. Lui, A. T. Y. and Meng, C. I.: 1979, J. Geophys. Res. 84, 5817.Google Scholar
  23. Obayashi, T.: 1975, Solar Phys. 40, 217.Google Scholar
  24. Pellinen, R. J. and Heikkila, W. J.: 1983, Space Sci. Rev. (in press).Google Scholar
  25. Priest, E. R. (ed.): 1981, Solar Magnetohydrodynamics, Gordon Breach Science Publ.Google Scholar
  26. Rust, D. M.: 1979, in E. N. Parker, C. F. Kennel, and L. J. Lanzerotti (eds.), Solar System Plasma Physics, Vol. I, North-Holland Publ. Co., Amsterdam, p. 51.Google Scholar
  27. Schindler, K.: 1974, J. Geophys. Res. 79, 28003.Google Scholar
  28. Schindler, K.: 1976, Solar Phys. 47, 91.Google Scholar
  29. Schindler, K. and Ness, N. F.: 1972, J. Geophys. Res. 77, 91.Google Scholar
  30. Spicer, D.: 1977, Solar Phys. 53, 305.Google Scholar
  31. Vasyliunas, V.: 1975, Rev. Geophys. Space Phys. 13, 303.Google Scholar
  32. Zwingmann, W.: 1983, submitted to J. Geophys. Res.Google Scholar

Copyright information

© D. Reidel Publishing Company 1983

Authors and Affiliations

  • Walter J. Heikkila
    • 1
  1. 1.CNET/CRPEIssy-les-MoulineauxFrance
  2. 2.Center for Space Sciences, University of Texas at DallasRichardsonUSA

Personalised recommendations