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The strong Pc5 geomagnetic pulsations in the initial phase of the great magnetic storm of March 24, 1991


Pc5 pulsations which were excited during the great magnetic storm of March 24, 1991 are analysed using the data from three French observatories located in the southern Indian Ocean at the subauroral and middle latitudes. The unusual strong Pc5 pulsations observed display features depending on the interval of occurrence: a quasi-noisy regime in the frequency range of 2.5–3.2 mHz characterizes the 04–10 UT interval, whereas the oscillations are nearly monochromatic with spectral maximum around 1.8–1.9 mHz in the 10–14 UT interval. The sharp change occurring at 10.17 UT could be associated to a sharp change in the magnetosphere structure or dynamics.


  1. Araki, T., S. Fujitani, M. Emoto, K. Yumoto, K. Shiokawa, T. Ichinose, H. Luehr, D. Orr, D. K. Milling, H. Singer, G. Rostoker, S. Tsunomura, Y. Yamada, and C. F. Liu, Anomalous sudden commencement on March 24, 1991, J. Geophys. Res., 102, 14075–14087, 1997.

  2. Bell, J. T., M. S. Gussenhoven, and E. G. Mullen, Super storms, J. Geophys. Res., 102, 14189–14198, 1997.

  3. Bolshakova, O. V., O. K. Borovkova, Yu. F. Borovkov, N. G. Kleimenova, and J. Bitterly, Magnetic storm on March 13, 1989: The structure of extremely disturbed magnetosphere obtained from geomagnetic pulsations Pc5, Geomagn. Aeron., 34, 492–500, 1995 (English ed.).

  4. Chen, L. and A. Hasegawa, A theory of long period magnetic pulsations. 1. Steady state excitation of field line resonance, J. Geophys. Res., 79, 1024–1037, 1974.

  5. Crowley, G., W. J. Hughes, and T. B. Jones, Observational evidence of cavity modes in the Earth’s magnetosphere, J. Geophys. Res., 92, 12233–12240, 1987.

  6. Dunlop, I. S., F. W. Menk, H. J. Hansen, B. J. Fraser, and R. J. Moris, A multistation study of long period geomagnetic pulsations at cusp and boundary layers latitudes, J. Atmos. Terr. Phys., 56, 667–679, 1994.

  7. Engebretson, M. J., L. J. Cahill, and D. J. Williams, Pulsations in magnetic field and ion flux observed at L = 4.5 on August 5 1972, J. Geophys. Res., 88, 161–173, 1983.

  8. Fujitani, S., T. Araki, K. Yumoto, K. Shiokawa, D. Orr, S. Tsunomura, Y. Yamada, H. Luhr, C. F. Lue, D. R. K. Rao, T. Kitamura, and K. Hayashi, Pc5 pulsations appeared on March 24 1991, STEPGBRSC-NEWS, 3, 15, 1993.

  9. Harrold, B. G. and J. C. Samson, Standing ULF modes of the magnetosphere: a theory, Geophys. Res. Lett., 19, 1811–1814, 1992.

  10. Kivelson, M. G., J. Etcho, and J. G. Trotignon, Global compressional oscillations of the terrestrial magnetosphere: the evidence and a model, J. Geophys. Res., 89, 9851–9856, 1984.

  11. Lam, H. L., A possible classification of Pc5 geomagnetic pulsations into two subgroups (Pc5A and Pc5B) based on spectral structure, J. Geomag. Geoelectr., 41, 813–834, 1989.

  12. Lam, H. L. and G. Rostoker, The relationship of Pc5 micropulsation activity in the morning sector to the auroral westward electrojet, Planet. Space Sci., 26, 473–492, 1978.

  13. Liu, J. Y., Y. N. Huang, and F. T. Berkey, The phase relationship between ULF geomagnetic pulsations and HF Doppler frequency shift oscillations on March 24, 1991, J. Geomag. Geoelectr., 45, 109–114, 1993.

  14. Reddy, C. A., S. Ravindran, K. S. Viswanathan, B. V. Krishna Murthy, D. R. K. Rao, and T. Araki, Observations of Pc5 micropulsation related electric field oscillations in the equatorial ionosphere, Ann. Geophys., 12, 565–573, 1994.

  15. Ruohoniemi, J. M., R. A. Greenwald, K. B. Baker, and J. C. Samson, Hf radar observations of Pc5 field line resonances in the midnight/early morning MLT sector, J. Geophys. Res., 96, 5697–15710, 1991.

  16. Samson, J. C. and B. J. Harrold, Field line resonances associated with MHD waveguides in the magnetosphere, Geophys. Res. Lett., 19, 441–444, 1992.

  17. Samson, J. C., R. A. Greenwald, J. M. Ruohoniemi, T. J. Hughes, and D. D. Wallis, Magnetometer and radar observations of magnetohydromagnetic cavity modes in the Earth’s magnetosphere, Can. J. Phys., 69, 929–937, 1991.

  18. Sonnerup, B. O., Theory of the low-latitude boundary layers, J. Geophys. Res., 85, 2017–2026, 1980.

  19. Southwood, D. J., Some features of field-line resonances in the magnetosphere, Planet. Space Sci., 22, 483–491, 1974.

  20. Walker, A. D. M., J. M. Ruohoniemi, K. B. Baker, R. A. Greenwald, and J. C. Samson, Spatial and temporal behavior of ULF pulsations observed by the Goose bay HF radar, J. Geophys. Res., 97, 12187–12202, 1992.

  21. Zhu, X. and M. G. Kivelson, Compressional ULF waves in the outer magnetosphere: 2. A case study of Pc5 type wave activity, J. Geophys. Res., 99, 241–252, 1994.

  22. Ziesolleck, C. W. S. and D. R. McDiarmid, Auroral latitude Pc5 field line resonances: Quantized frequencies, spatial characteristics and diurnal variation, J. Geophys. Res., 99, 5817–5830, 1994.

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Correspondence to J. J. Schott.

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Schott, J.J., Kleimenova, N.G., Bitterly, J. et al. The strong Pc5 geomagnetic pulsations in the initial phase of the great magnetic storm of March 24, 1991. Earth Planet Sp 50, 101–106 (1998).

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  • Magnetic Storm
  • Geomagnetic Pulsation
  • Solar Wind Dynamic Pressure
  • Sudden Commencement
  • Strong Magnetic Storm