Physics of auroral phenomena : proceedings of the 34th Annual seminar, Apatity, 01 - 04 March, 2011 / [ed.: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2011. - 231 с. : ил.

V.B. Belakhovsky et al. We could not identify clear signatures of Pc5 pulsations in the radar data of plasma density, ion and electron temperature along the latitude profile. However, Pc5 pulsations were observed in the cosmic noise absorption (CNA) at IRIS riometer in Kilpisjarvi and also pulsations of the same frequency were seen in the flux of electrons with energy 50-75 keV at.L4M.-01 geostationary spacecraft. 4. Discussion and conclusions In the present study we considered the morning toroidal geomagnetic Pc5 pulsations and associated pulsations in ionosphere plasma velocity. It was observed that the frequency of Pc5 pulsations of ionospheric plasma velocity associated with toroidal geomagnetic Pc5 pulsations decreased with geomagnetic latitude. Earlier Walker et al. [1992] observed such a decrease of the frequency of ULF pulsations with latitude, but they investigated the ULF oscillations of ionosphere plasma velocity in the night sector (01.00-04.00 MLT). These ULF oscillations should be classified as the Pi3 pulsations associated with the substorm. These authors did not use data of geomagnetic filed. Indeed, it is not clear whether these oscillations were indicating geomagnetic Pc5 pulsations or just ionosphere noise. Thus, we demonstrate the possibility to determine the latitude distribution of the resonance frequency of Pc5 pulsations using data from the single EISCAT radar. Acknowledgements. We are indebted to the Director and staff of EISCAT for operating the facility and supplying the data. EISCAT is an international association supported by research organisations in China (CRIRP), Finland (SA), France (CNRS, till end 2006), Germany (DFG), Japan (NIPR and STEL), Norway (NFR), Sweden (VR), and the United Kingdom (STFC). We thank the Finnish Meteorological Institute and other institutes who maintain the IMAGE magnetometer array. Work of AK was supported by the Academy of Finland project 115920. Work of VB was partially supported by the The Finnish Academy of Science and Letters Vilho, Yijo and Kalle Vaisala Foundation. The work is supported by the Russian Foundation for Basic Research (grants 10-05-90716 and 09-05-00818) and by Presidium of the Russian Academy of Science (Program 4). References 1. Allan W., Poulter E. М., Nielsen E. STARE observations of a Pc 5 pulsation with large azimuthal wave number // Journal of Geophys. Res. vol. 87. № 8. P. 6163-6172. 1982. 2. Buchert S.C., R. Fujii, K.-H. Glassmeier. Ionospheric conductivity modulation in ULF pulsations // J. Geophys. Res. V. 104. A5. 10119-10133. 1999. 3. Lathuillere C., GlangeaudF., ZhaoZ. Y. Ionospheric ion heating by ULF Pc 5 magnetic pulsations // J. Geophys. Res. 91. 1619-1626. 1986. 4. Walker A.D.M., Greenwald R.A., Stuart W.F., Green C.A. Stare auroral radar observations of Pc5 geomagnetic pulsations // J. Geophys. Res. V. 84. № A7. P. 3373- 3388. 1979. 5. Walker A.D.M., Ruohoniemi J.M., Baker K.B., Greenwald R.A., Samson J.C. Spatial and temporal behavior of ULF pulsations observed by the Goose Bay HF radar // J. Geophys. Res. V. 97. № A8. P. 12187-12202. doi: 10.1029/92JA00329. 1992. 74