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Longitudinal dependence of characteristics of low-latitude Pi2 pulsations observed at Kakioka and Hermanus


We statistically investigated longitudinal dependence of characteristics of low-latitude Pi2 pulsations to find the longitudinal structure of the plasmaspheric cavity mode. We used the geomagnetic field data from two ground stations, Kakioka (27.2° geomagnetic latitude, 208.5° geomagnetic longitude) and Hermanus (—33.9° geomagnetic latitude, 82.2° geomagnetic longitude), and auroral image data acquired by the ultraviolet imager onboard the Polar satellite for the period of December 4, 1996 to March 3, 1997. Our findings include the following: (1) Pi2 amplitude is the largest around the magnetic local time of the auroral breakup site and decreases away from it; (2) when a nightside Pi2 pulsation has large amplitude, a dayside Pi2 pulsation can be observed with a similar waveform; (3) Pi2 pulsations generally have no clear phase differences (mean phase difference of 3.3°) between Kakioka and Hermanus, except for some events; and (4) the phase difference is independent on AMLT (difference of magnetic local time between a station and the auroral breakup). These observations suggest that the plasmaspheric cavity mode can be excited globally with a very small value of the azimuthal wave number (m 0).


  1. Brittnacher, M., R. Elsen, G. Parks, L. Chen, G. Germany, and J. Spann, A dayside auroral energy deposition case study using Polar Ultraviolet Imager, Geophys. Res. Lett., 24, 991–994, 1997.

  2. Fujita, S. and K.-H. Glassmeier, Magnetospheric cavity resonance oscillations with energy flow across the magnetopause, J. Geomagn. Geo-electr., 47, 1277–1292, 1995.

  3. Fujita, S. and M. Itonaga, A plasmaspheric cavity resonance in a longitudinally non-uniform plasmasphere, Earth Planets Space, 55, 219–222, 2003.

  4. Fujita, S., M. Itonaga, and H. Nakata, Relationship between the Pi2 pulsations and the localized impulsive current associated with the current disruption in the magnetosphere, Earth Planets Space, 52, 267–281, 2000.

  5. Fujita, S., H. Nakata, M. Itonaga, A. Yoshikawa, and T. Mizuta, A numerical simulation of the Pi2 pulsations associated with the substorm current wedge, J. Geophys. Res., 107(A3), DOI 10.1029/2001JA900137, 2002.

  6. Han, D., T. Iyemori, Y. Gao, Y. Sano, F. Yang, W. Li, and M. Nosé, Local time dependence of the frequency of Pi2 waves simultaneously observed at 5 low-latitude stations, Earth Planets Space, 55, 601–612, 2003.

  7. Han, D., T. Iyemori, M. Nosé, H. McCreadie, Y. Gao, F. Yang, S. Ya-mashita, and P. Stauning, A comparative analysis of low-latitude Pi2 pulsations observed by Ørsted and ground stations, J. Geophys. Res., 109, A10209, doi:10.1029/2004JA010576, 2004.

  8. Keiling, A., J. R. Wygant, C. Cattell, K.-H. Kim, C. T. Russell, D. K. Milling, M. Temerin, F. S. Mozer, and C. A. Kletzing, Pi2 pulsations observed with the Polar satellite and ground stations: Coupling of trapped and propagating fast mode waves to a midlatitude field line resonance, J. Geophys. Res., 106, 25,891–25,904, 2001.

  9. Kim, K.-H., K. Takahashi, D.-H. Lee, N. Lin, and C. A. Cattell, A comparison of Pi2 pulsations in the inner magnetosphere and magnetic pulsations at geosynchronous orbit, J. Geophys. Res., 106, 18,865–18,872, 2001.

  10. Kitamura, T., O. Saka, M. Shimoizumi, H. Tachihara, T. Oguti, T. Araki, N. Sato, M. Ishitsuka, O. Veliz, and J. B. Nyobe, Global mode of Pi2 waves in the equatorial region: Difference of Pi2 mode between high and equatorial latitudes, J. Geomagn. Geoelectr., 40, 621–634, 1988.

  11. Kosaka, K., T. Iyemori, M. Nosé, M. Bitterly, and J. Bitterly, Local time dependence of the dominant frequency of Pi2 pulsations at mid- and low-latitudes, Earth Planets Space, 54, 771–781, 2002.

  12. Kurchashov, Y. P., Y. S. Nikomarov, V. A. Pilipenko, and A. Best, Field line resonance effects in local meridional structure of mid-latitude geomagnetic pulsations, Ann. Geophys., 5A, 147–154, 1987.

  13. Lee, D.-H. and R. L. Lysak, MHD waves in a three-dimensional dipolar magnetic field: A search for Pi2 pulsations, J. Geophys. Res., 104, 28,691–28,699, 1999.

  14. Li, Y., B. J. Fraser, F. W. Menk, D. J. Webster, and K. Yumoto, Properties and sources of low and very low latitude Pi2 pulsations, J. Geophys. Res., 103, 2343–2358, 1998.

  15. Lin, C. C. and L. J. Cahill, Jr., Pi2 pulsations in the magnetosphere, Planet. Space. Sci., 23, 693–711, 1975.

  16. Liou, K., P. T. Newell, C. -I. Meng, M. Brittnacher, and G. Parks, Char-acteristics of the solar wind controlled auroral emissions, J. Geophys. Res., 103, 17,543–17,557, 1998.

  17. Liou, K., C. -I. Meng, P. T. Newell, K. Takahashi, S. -I. Ohtani, A. T. Y. Lui, M. Brittnacher, and G. Parks, Evaluation of low-latitude Pi2 pulsations as indicators of substorm onset using Polar ultraviolet imagery, J. Geophys. Res., 105, 2495–2505, 2000.

  18. Matsuoka, H., K. Takahashi, S. Kokubun, K. Yumoto, T. Yamamoto, S. I. Solovyev, and E. F. Vershinin, Phase and amplitude structure of Pc3 magnetic pulsations as determined from multipoint observations, J. Geophys. Res., 102, 2391–2403, 1997.

  19. Nosé, M., K. Takahashi, T. Uozumi, K. Yumoto, Y. Miyoshi, A. Morioka, D. K. Milling, P. R. Sutcliffe, H. Matsumoto, T. Goka, and H. Nakata, Multipoint observations of a Pi2 pulsation on morningside: The 20 September 1995 event, J. Geophys. Res., 108(A5), 1219, doi:10.1029/2002JA009747, 2003.

  20. Oowada, T., T. Tokumoto, Y. Yamada, M. Ozima, N. Kumasaka, M. Yokoyama, M. Sugawara, K. Koike, and Y. Shimizu, Technical Report of the Kakioka Magnetic Observatory, Supplement, 1, pp. 1–14, 2003.

  21. Osaki, H., K. Yumoto, K. Fukao, K. Shiokawa, F. W. Menk, B. J. Fraser, and the 210° MM Magnetic Observation Group, Characteristics of low-latitude Pi2 pulsations along the 210° magnetic meridian, J. Geomagn. Geoelectr., 48, 1421–1430, 1996.

  22. Sakurai, T. and R. L. McPherron, Satellite observations of Pi2 activity at synchronous orbit, J. Geophys. Res., 88, 7015–7027, 1983.

  23. Sastry, T. S., Y. S. Sarma, S. V. Sarma, and P. V. S. Narayan, Day-time Pi pulsations at equatorial latitudes, J. Atmos. Terr. Phys., 45, 733–741, 1983.

  24. Shinohara, M., K. Yumoto, A. Yoshikawa, O. Saka, S. I. Solovyev, E. F. Vershinin, N. B. Trivedi, J. M. Da Costa, and The 210? MM Magnetic Observation Group, Wave characteristics of daytime and nighttime Pi2 pulsations at the equatorial and low latitudes, Geophys. Res. Lett., 24, 2279–2282, 1997.

  25. Sutcliffe, P. R. and H. Lühr, A comparison of Pi2 pulsations observed by CHAMP in low Earth orbit and on the ground at low latitudes, Geophys. Res. Lett., 30(21), 2105, doi:10.1029/2003GL018270, 2003.

  26. Takahashi, K., S. Ohtani, and B. J. Anderson, Statistical analysis of Pi2 pulsations observed by the AMPTE CCE spacecraft in the inner magnetosphere, J. Geophys. Res., 100, 21,929–21,941, 1995.

  27. Takahashi, K., W. J. Hughes, R. R. Anderson, and S. I. Solovyev, CR-RES satellite observations associated with low-latitude Pi2 pulsations, J. Geophys. Res., 104, 17,431–17,440, 1999a.

  28. Takahashi, K., B. J. Anderson, and K. Yumoto, Upper Atmosphere Research Satellite observation of a Pi2 pulsation, J. Geophys. Res., 104, 25,035–25,045, 1999b.

  29. Takahashi, K., S. Ohtani, W. J. Hughes, and R. R. Anderson, CRRES observation of Pi2 pulsations: Wave mode inside and outside the plasmas-phere, J. Geophys. Res., 106, 15,567–15,581, 2001.

  30. Takahashi, K., D.-H. Lee, M. Nosé, R. R. Anderson, and W. J. Hughes, CR-RES electric field study of the radial mode structure of Pi2 pulsations, J. Geophys. Res., 108(A5), 1210, doi:10.1029/2002JA009761, 2003a.

  31. Takahashi, K., R. R. Anderson, and W. J. Hughes, Pi2 pulsations with second harmonic: CRRES observations in the plasmasphere, J. Geophys. Res., 108(A6), 1242, doi:10.1029/2003JA009847, 2003b.

  32. Torr, M. R., et al., A far ultraviolet imager for the international solar-terrestrial physics mission, Space Sci. Rev., 71, 329–380, 1995.

  33. Yumoto, K., Generation and propagation mechanisms of low-latitude magnetic pulsations, A review, J. Geophys., 60, 79–105, 1986.

  34. Yumoto, K., Y. Tanaka, T. Oguti, K. Shiokawa, Y. Yoshimura, A. Isono, B. J. Fraser, F. W. Menk, J. W. Lynn, M. Seto, and 210? MM Magnetic observation Group, Globally coordinated magnetic observations along 210? Magnetic Meridian during STEP period: 1. Preliminary results of low-latitude Pc3’s, J. Geomagn. Geoelectr., 44, 261–276, 1992.

  35. Yumoto, K., H. Osaki, K. Fukao, K. Shiokawa, Y. Tanaka, S. I. Solovyev, G. Krymskij, E. F. Vershinin, V. F. Osinin, and 210? MM Magnetic Observation Group, Correlation of high- and low-latitude Pi2 magnetic pulsations observed at 210? magnetic meridian chain stations, J. Geomagn. Geoelectr., 46, 925–935, 1994.

  36. Yumoto, K. and the CPMN Group, Characteristics of Pi2 magnetic pulsations observed at the CPMN stations: A review of the STEP results, Earth Planets Space, 53, 981–992, 2001.

  37. Ziesolleck, C. W. S., B. J. Fraser, F. W. Menk, and P. W. McNabb, Spatial characteristics of low-latitude Pc3-4 geomagnetic pulsations, J. Geo-phys. Res., 98, 197–207, 1993.

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Nosé, M., Liou, K. & Sutcliffe, P.R. Longitudinal dependence of characteristics of low-latitude Pi2 pulsations observed at Kakioka and Hermanus. Earth Planet Sp 58, 775–783 (2006).

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Key words

  • Pi2 pulsation
  • plasmaspheric cavity mode