Space Science Reviews

, Volume 4, Issue 4, pp 498–540 | Cite as

Dynamic morphology of auroras

  • Syun-Ichi Akasofu


Simultaneous changes of auroral forms, brightness, and motions over the whole polar region are studied, using IGY all-sky camera records from widely distributed stations in eastern Siberia, Alaska, Canada and the northern United States. It is found that the auroral system centered in the midnight sector in the auroral zone repeatedly undergoes an expansion and subsequent contraction; during the maximum stage of the activity, the whole auroral system extends over a substantial portion of the darkened polar region. Such extensive auroral activity as a whole may be regarded as a single event, and is described in terms of the auroral substorm. The substorm has two characteristic phases, an expansive phase and a recovery phase. Characteristic auroral displays over the entire polar region during the substorm are described in detail. The basic physical processes involved for the auroral substorm are also discussed.

Geomagnetic disturbances associated with the auroral substorm are also described in detail in terms of the polar magnetic substorm, and it is shown that both the auroral substorm and the polar magnetic substorm are different aspects of the manifestation of a large-scale plasma motion in the magnetosphere.

The distribution of the aurora for different degrees of the geomagnetic activity is also discussed in terms of the auroral belt. It is shown that the center line of the auroral belt moves greatly with respect to its average location (namely the auroral zone), depending on the degree of the magnetic activity.


Polar Region Geomagnetic Activity Geomagnetic Disturbance Auroral Zone Auroral Activity 
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  1. Akasofu, S.-I.: 1960, ‘Large-scale auroral motions and polar magnetic disturbances, I’, J. Atm. Terr. Phys. 19, 10–25.Google Scholar
  2. Akasofu, S.-I.: 1963, ‘The dynamic morphology of the aurora polaris’, Annals of IGY XX, Part IV, pp. 331–364; J. Geophys. Res. 68, 1667–1673.Google Scholar
  3. Akasofu, S.-I.:1963, ‘The auroral rays’, J. Atm. Terr. Phys. 25, 163–165.Google Scholar
  4. Akasofu, S.-I.: 1964, ‘The development of the auroral substorm’, Planet. Space Sci. 12, 273–282.Google Scholar
  5. Akasofu, S.-I.: 1964, ‘The latitudinal shift of the auroral belt’, J. Atm. Terr. Phys. 26, 1167.Google Scholar
  6. Akasofu, S.-I. and Chapman, S.: 1963, ‘The lower limit of latitude (U.S. sector) of northern quiet auroral arcs, and its relation to Dst (H)’, J. Atm. Terr. Phys. 25, 9–12.Google Scholar
  7. Akasofu, S.-I. and Chapman, S.: 1963, ‘Simultaneous development of the main phase (DR) and of polar magnetic storms (DP)’, J. Geophys. Res. 68, 3155–3158.Google Scholar
  8. Akasofu, S.-I., Kimball, D. S., and Meng, C.-I.: 1965a, ‘The dynamics of the aurora — II’, J. Atm. Terr. Phys. 27, 173.Google Scholar
  9. Akasofu, S.-I., Kimball, D. S., and Meng, C.-I.: 1965b, ‘The dynamics of the aurora — III’ J. Atm. Terr. Phys. 27, 189.Google Scholar
  10. Akasofu, S.-I., Chapman, S., and Meng, C.-I.: 1965, J. Atm. Terr. Phys. (in press).Google Scholar
  11. Axford, W. I. and Hines, C. O.: 1961, ‘A unifying theory of high-latitude geophysical phenomena and geomagnetic storms’, Can. J. Phys. 39, 1433–1464.Google Scholar
  12. Chamberlain, J. W.: 1961, Physics of the Aurora and Airflow, Academic Press, 704 pp.Google Scholar
  13. Chapman, S.: 1953, ‘The equatorial electrojet as detected from the abnormal electric current distribution above Huancayo, Peru and elsewhere’, Arch. Met. Geoph. Bioki. AIV, 368–390.Google Scholar
  14. Cole, K. D.: 1960, ‘A dynamo theory of the aurora and magnetic disturbance’, Australian J. Phys. 13, 484–497.Google Scholar
  15. Cole, K. D.: 1963, ‘Motions of the aurora and radio-aurora and their relationships to ionospheric currents’, Planet. Space Sci. 10, 129–164.Google Scholar
  16. Davis, T. N.: 1962, ‘The morphology of the polar aurora’, J. Geophys. Res. 65, 3497–3500; 67, 75–110.Google Scholar
  17. Davis, T. N.: 1963, ‘Negative correlation between polar cap visual aurora and magnetic activity’, J. Geophys. Res. 68, 4447–4453.Google Scholar
  18. Denholm, J. V.: 1961, ‘Some auroral observations inside the southern auroral zone’, J. Geophys. Res. 66, 2105–2111.Google Scholar
  19. Fejer, J. A.: 1964, ‘Theory of the geomagnetic daily disturbance variations’, J. Geophys. Res. 69, 123–137.Google Scholar
  20. Feldstein, Y. L.: 1960, ‘Geographic distributions of aurora and azimuth of auroral arcs’, Investigations of the Aurora USSR 5, 61–78.Google Scholar
  21. Feldstein, Y. I., Khokosheva, O. V., and Lebedinsky, A. I.: 1962, J. Phys. Soc. Japan 17 (Intern. Cont. Cosmic Rays and Earth Storm, Part I, 249–254).Google Scholar
  22. Feldstein, Y. I.: 1963, ‘Space-time distribution of magnetic activity at high latitudes of the northern hemisphere’. Results of Researches of the Programm of the IGY, No. 5.Google Scholar
  23. Feldstein, Y. I.: 1964, ‘Auroral morphology, I, The location of the auroral zone’, Tellus 16, 252–257.Google Scholar
  24. Feldstein, Y. I.: 1964, ‘Auroral morphology, II, auroral and geomagnetic disturbances’, Tellus 16, 258–267.Google Scholar
  25. Heppner, J. P.: 1954, ‘Time sequences and spatial relations in auroral activity during magnetic bays at College, Alaska’, J. Geophys. Res. 59, 329–338.Google Scholar
  26. Horoševa, O. V.: 1963, ‘The diurnal drift of the closed auroral ring’, Geomagnetizm iaeronomija 2, 696–705.Google Scholar
  27. Hultquist, B.: 1962, ‘On the orientation of auroral arcs’, J. Atm. Terr. Phys., 24, 17–30.Google Scholar
  28. Kern, I. W.: 1962, ‘A charge separation mechanism for the production of polar cap auroras and electrojets’, J. Geophys. Res. 67, 2649–2665.Google Scholar
  29. Lassen, K.: 1959, ‘Existence of an inner auroral zone’, Nature, Lond. 184, 1375–1377: ‘Local aurorae in the morning hours at Godhaven, Greenland’, Det Canske Meteorologiske Institute, Comtn. Mag. No.24, Charlottenland, 1959.Google Scholar
  30. McEwen, D. J. and Montalbetti, R.: 1958, ‘Parallactic measurements on aurorae over Churchill, Canada’, Canad. J. Phys. 36, 1593–1600.Google Scholar
  31. Meng, C.-I.: 1965, MS Thesis, Geophysical Institute, University of Alaska.Google Scholar
  32. Nagata, T. and Kokubun, S.: 1960, ‘On the earth storms, 4. Polar magnetic storms with special reference to relation between geomagnetic disturbances in the northern and sourhtern auroral zones’, Rep. Ionosphere Res. Japan 14, 273–290.Google Scholar
  33. Romick, G. J. and Belon, A. E.: 1964, ‘The determination of the spatial distribution of auroral luminosity’, Geophys. Inst., Univ. of Alaska Pub. Google Scholar
  34. Wescott, E.: 1962, ‘Magnetic activity during period of auroras at geomagnetically conjugate points’, J. Geophys. Res. 67, 1353–1355.Google Scholar

Copyright information

© D. Reidel Publishing Company 1965

Authors and Affiliations

  • Syun-Ichi Akasofu
    • 1
  1. 1.Geophysical InstituteUniversity of Alaska College

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