Results

During the second stage of the project №14-37-00027 we obtained the following main results.

  1. We derived the Alfven mode equation for finite-pressure space plasma in curved magnetic field, using gyrokinetic approach. We used long plasma approximation, where wave frequency is much higher than the bounce frequency. The Alfven mode modified by the field line curvature, plasma finite-pressure and equilibrium current effects is the only MHD wave mode exists in plasma for long plasma approximation. Due to these effects the Alfven mode acquires considerable oscillatory magnetic field component parallel to background magnetic field. It means that, unlike the Alfvén mode in homogeneous cold plasma, here Alfvén mode become compressional wave. [Dmitri Yu. Klimushkin, Pavel N. Mager. The Alfven mode gyrokinetic equation in pressure magnetospheric plasma // J. Geophys. Res. SpacePhysics. 2015. V. 120, P. 4465–4474, doi:10.1002/2015JA021045].
  2. For the first time, monochromatic standing poloidal Alfven wave transformation into a toroidal wave has been observed. A theoretical interpretation for Alfven-type monochromatic oscillations is proposed. These oscillations are observed by the Radiation Belt Storm Probes (RBSP)-A satellite on 23 October 2012 when crossing the plasmapause at 21.45–22.30 UT. It is shown that a poloidal Alfven wave transforms into a toroidal Alfven wave in the process under consideration. [Leonovich A.S., Klimushkin D.Yu., Mager P.N. Experimental evidence for existence of monochromatic transverse small-scale standing Alfven waves with spatially depending polarization // J. Geophys. Res. Space Physics. 2015. V. 120, P. 5443–5454, doi:10.1002/2015JA021044].
  3. We suggested an explanation of drift of auroras recorded at the Shamattawa station (66,3° N, 336,0° E in corrected geomagnetic coordinates) prior to substorm. We believe the drifts are generated by standing Alfven waves. [Saka O., Hayashi K., Leonovich A.S. Ionospheric loop currents and associated ULF oscillations at geosynchronous altitudes during preonset intervals of substorm aurora // J. Geophys. Res. Space Physics, 2015. V. 120. P. 2460-2468. doi:10.1002/2014JA020842].
  4. We have developed two-dimensional model for analytical investigation of waveguide for fast magnetosonic waves in the outer magnetosphere. We have found out that the waveguide eigenmodes and corresponding Alfvén resonance regions are directly related to geomagnetic pulsations Pc3 and Pc5. [V.A.Mazur, D.A. Chuiko. Azimuthal inhomogeneity in the MHD waveguide in the outer magnetosphere // J. Geophys. Res. Space Physics. 2015. V. 120, 4641–4655, doi:10.1002/2014JA020819].
  5. We have proposed a new approach for ionospheric Alfvén resonator (IAR) emission investigation. We used the IRI-2012 version of the International Reference Ionosphere model to predict the difference between frequencies of adjacent harmonics of the IAR emission. The experimental and modeled data agree at both mid-latitude and high latitude regions. [Potapov A.S., Polyushkina T.N., Dovbnya B.V. Use of the International Reference Ionosphere 2012 model to calculate emission frequency scale of the ionospheric Alfvén resonator // J. Space Weather Space Clim., 2015, V. 5, A14, DOI: 10.1051/swsc/2015018].
  6. Using the spectral measurements of hydroxyl molecule radiation, we developed a technique for comprehensive analysis of atmospheric and ionospheric variability. The technique illuminates the dynamic interconnections between different atmosphere regions. As a characteristic of the atmospheric variability that we can compare with ionospheric parameters variations, we proposed to use the atmosphere temperature variability at the mesopause height. We analyzed the seasonal variation of the atmospheric day-to-day variability and observed well-pronounced maxima, caused by planetary waves, in winter and equinoxes. [Medvedeva I., Ratovsky K. Studying atmospheric and ionospheric variabilities from long-term spectrometric and radio sounding measurements // J. Geophys. Res. Space Physics, 2015. V. 120, P. 5151–5159, doi:10.1002/2015JA021289].
  7. We developed a technique for meridional winds velocity determination using Irkutsk Incoherent Scatter Radar (IISR) data. The technique takes into account IISR individual design. We obtained plasma drift velocity along two radar beams based on autocorrelation function phase analysis. [Shcherbakov A.A., Medvedev A.V., Kushnarev D.S., Tolstikov M.V., Alsatkin S.S. Calculation of meridional neutral winds in the middle latitudes from the Irkutsk incoherent scatter radar // J. Geophys. Res. Space Physics, 2015. V. 120, doi:10.1002/2015JA021678].
  8. Using numerical simulation, we demonstrated the capability of reducing the residual ionospheric error in multi-frequency GNSS remote sensing of the ionosphere and the troposphere. The error reduction is based on Fresnel inversion. [M.V. Tinin. Influence of Ionospheric Irregularities on GNSS Remote Sensing // Advances in Meteorology, 2015, V. 2015, Article ID 532015, 10 pages, http://dx.doi.org/10.1155/2015/532015].
  9. We have developed a technique for recording slips in GPS navigation service. Using this technique we have carried out an analysis of GPS slips continuous time series measured for 2010-2014. The probability of TEC determination slip was found to be in 100-200 times higher than just instrumental slips. Both TEC and instrumental slips probability increase during various helio- and geomagnetic disturbances. [V.I. Zakharov, Yu.V. Yasyukevich, M.A. Titova. Storms and substorms influence on GPS slips at high latitude // Cosmic Research, 2016, V 54, N 1, P. 1–11].
  10. We have upgraded the algorithm for absolute vertical total electron content (TEC) determination to increase the temporal resolution up to 15 minutes. We found out significant discrepancy between the published GLONASS differential code biases (DCB) and our estimations. It results in unphysical TEC values when using GLONASS DCB published by CODG laboratory in the Arctic region. [Yu. V. Yasyukevich, A. A. Mylnikova, V. E. Kunitsyn, A. M. Padokhin. Influence of GPS/GLONASS Differential Code Biases on the Determination Accuracy of the Absolute Total Electron Content in the Ionosphere // Geomagnetism and Aeronomy, 2015, V. 55, N 6, P. 763–769]

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