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.

Yu. Cherniak et al. The EISCAT facilities position provides the unique opportunity to study the ionospheric irregularities’ parameters associated with TEC fluctuations and GPS/GLONASS signals scintillations. To estimate the ionosphere irregularities we used the IS radar measurements (electron density and plasma temperatures profiles) and simultaneously registered on EISCAT site amplitude and phase fluctuations in GPS/GLONASS signals by use of the TRIUMPH- Javad GNSS receiver with high samples rate (100 Hz) and special scintillation GPS receiver (Septentrio PolaRxS) that provides S4 scintillation index measurements. The low frequency fluctuations were estimated using ROT and ROTI indices along the radio ray path2 between a GPS/GLONASS satellite and a ground station on EISCAT site. Results The measurements were carried out on 7-12 June 2012, the active experiment with UHF IS radar and heating facility was on 7-8 June, other time was devoted to estimation of GNSS signal parameters day-to day variability. The total durations of radar measurements was 8,5 h, that covers from 11:00 to 15:30 UT on 7 June 2012 and from 17:00 to 21:00 UT on 8 June. The heating facility was operated during 30 min between 18:30 and 19:00 7 June and 8 June during 1 hour from 13:00 to 14:00 and 30 min from 15:00 to 15:30. The UHF radar measurements provide information about height-temporal distribution of main ionosphere parameters - electron density, electron and ion temperatures and plasma drift velocity. Fig. 1 demonstrated variations of these parameters for radar experiment time. Unfortunately due to absorption of HF radio waves from heating facility caused by particles precipitation the heating effect was not pronounced in density and temperature variations. TROl 2012 e 7 CPS 25 12.0 UT, h 13.0 14.0 15.0 ie.0 Figure 2. The S4 index variations for 7 and 8 June, EISCAT site placed GNSS receivers. The analysis of amplitude and S4 index variation from GNSS receivers shows amplifications of fluctuations activity during period’s corresponded to the heating facility runs. Fig. 2 presents variations of S4 index for GPS satellite N25 (7 June from 14:30) and GLONASS satellite N11 (8 June from 14:30). It was observed unusual rising of S4 index with factor 2 (after 18 UT) for GPS and with factor 3 (after 13 UT) for GLONASS satellites. Figure 3. The 84 space weather parameter for periods before, during and after experiment time.