Physics of auroral phenomena : proceedings of the 37th Annual seminar, Apatity, 25 - 28 February, 2014 / [ed. board: A. G. Yahnin, N. V. Semenova]. - Апатиты : Изд-во Кольского научного центра РАН, 2014. - 125 с. : ил., табл.

N.G. Kleimenova et al. It is seen that the relative width of the Pci wave spectra £ = |^A©/(fi. / t )1/2j increases with the (к ,/ t /ц) increasing. The anisotropy also controls the wave spectral width - with increasing anisotropy A , for fixed the value of parameter {ул /Ц,)» the spectral width decreases. Conclusion During the minimum of the solar activity (2006-2009) and the beginning of the new cycle (2009- 2012), the common annual duration of the long-lasting series (more 2 hours) of the Pci geomagnetic pulsation was controlled by the cycle variations of the solar and geomagnetic activity. The long-lasting Pci pulsation series were observed mostly during a late recovery phase of magnetic storms and disturbances. In the solar activity minimum, the shape of the dynamic Pci spectra looked like a very monochromatic emission of a rather short (not more 3-5 hours) duration with a low central frequency (less than 1 Hz) and a narrow width (~0.2-0.3 Hz) of the dynamic spectra. However, during the declining (2006) and increasing (2010) phases of the solar activity, the spectral structure of Pci became more complicated and the duration of the Pci series increased up to 10-12 hours. The central frequency of the Pci series and the width of the wave dynamic spectra significantly increased. Sometimes it consisted of several varying frequency bands. The theoretical interpretation showed the width of the Pci spectra is controlled by an important magnetospheric parameters / [ / J and anisotropy A , where VA is the Alfven speed in the top of the magnetic field line, and U ц is the average field-along speed of the anisotropic protons. Acknow ledgements. The paper was supported by the Program No 4 of the Presidium o f the Russian Academy of Sciences (RAS) and partly by the RFBR Grants № 14-05-00850. References Cornwall J. M. Cyclotron instabilities and electromagnetic emission in the ultra low frequency and very low frequency ranges // J. Geophys. Res., 70(1), 61-69, doi:10.1029/JZ070i001p00061 1965. Demekhov A.G. Recent progress in understanding Pci pearl formation // J. Atm. Solar-Terr. Phys. V. 69. P. 1609- 1622. 2007. Feygin F.Z, Yakimenko V.L. Appearance and development of geomagnetic Pci type micropulsations ("pearls") due to cyclotron instability of proton belt // Ann. Geophys. V.27. P. 49-55. 1971 Fraser-Smith A.C. Some statistics on Pc 1 geomagnetic micropulsation occurrence at middle latitudes: Inverse relation with sunspot cycle and semi-annual period // J. Geophys. Res. V. 75. P. 4735-4745, doi:10.1029/JA075i025p04735, 1970. Gendrin R., Lacourly S., Roux A., Solomon J., Feygin F.Z., Gokhberg M.B., Troitskaya V.A., Yakimenko V.L. Wave packet propagation in an amplifying medium and its application to the dispersion characteristics and to the generation mechanism of Pci events // Planet. Space Sci. V. 19. P. 165-194. 1971. Guglielmi A., Kangas J. Pci waves in the system of solar-terrestrial relations: New reflections // J. Atmos. Solar- Terr. Phys. V.69. P. 1635-1643, doi: 10.1016/j.jastp.2007.01.015, 2007. Guglielmi A., Pokhotelov O. Nonlinear problems of physics of the geomagnetic pulsations // Space Sci. Rev. V. 65. P. 5-57. 1994. Kangas J., Guglielmi A., Pokhotelov O. Morphology and physics of short-period magnetic pulsations // Space Sci. Rev. V.83. P. 435-512. 1998. Kennel C.F., Petschek H.E.. Limit on stably trapped particle fluxes // J. Geophys. Res. V. 71(1). P. 1-28. doi: 10.1029/JZ071iOO1pOOOO1. 1966. Lin R.-L., Zhang J.-C., Allen R.C., Kistler L.M., Mouikis C.G., Gong J.-C., Liu S.-Q., Shi L.-Q., Klecker B., Sauvaud J.-A., Dunlop M.W. //Testing linear theory of EMIC waves in the inner magnetosphere: Cluster observations // J. Geophys. Res. V. 119. P. 1004-1027. doi: 10.1002/2013JA01954. 2014. Matveeva E.T. Cyclic variation of geomagnetic Pci activity // Geomagnetism and Aeronomy V. 27. No.3. P. 392- 395. 1987. Min K , Lee J., Keika K, Li W. Global distribution of EMIC waves derived from THEMIS observations // J. Geophys. Res. V. 117. A05219, doi:10.1029/2012JA017515. 2012. Mursula K , Kangas J., Pikkarainen Т., Kivinen M. Pci micropulsations at a high-latitude station: A study over nearly four solar cycles H i. Geophys. Res. V. 96. P. 17651-17661, doi:10.1029/91JA01374, 1991. Park J., Liihr H., Rauberg J. Global characteristics of Pci magnetic pulsations during solar cycle 23 deduced from CHAMP data // Ann. Geophys. V. 31. P. 1507-1520. 2013. 66