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Non-Gaussian transport, strong turbulence, and nonlinear phenomena in the magnetosphere and ionosphere (06-1000017-8943)


Funded by

INTAS

Start Date: 2007-12-03       End Date: 2009-02-03

The macroscopic consequences of nonlinear solitary vortex structures in magnetized space plasmas by developing theoretical model of plasma turbulence is investigated within the framework of the project. Strongly localized vortex patterns contain trapped particles and, propagating in a medium, excite substantial density fluctuations and thus, intensify the energy, heat and mass transport processes, i.e., such vortices can form strong vortex turbulence. Turbulence is represented as an ensemble of strongly localized (and therefore weakly interacting) vortices. Vortices with various amplitudes are randomly distributed in space (due to collisions). For their description, a statistical approach is applied. It is supposed that a stationary turbulent state is formed by balancing competing effects: spontaneous development of vortices due to nonlinear twisting of the perturbations’ fronts, cascading of perturbations into short scales (direct spectral cascade) and collisional or
collisionless damping of the perturbations in the short-wave domain. In the inertial range, direct spectral cascade occurs through merging structures via collisions. It is shown that in the magneto-active plasmas, strong turbulence is generally
anisotropic Turbulent modes mainly develop in the direction perpendicular to the local magnetic field. It is found that it is the compressibility of the local medium which primarily determines the character of the turbulent spectra: the strong vortex turbulence forms a power spectrum in wave number space. For example, a new spectrum of turbulent fluctuations in k−8/3 is derived which agrees with available experimental data. Within the framework of the developed model particle
diffusion processes are also investigated. It is found that the interaction of structures with each other and particles causes anomalous diffusion in the medium. The effective coefficient of diffusion has a square root dependence on the stationary level of noise.

Project members:

Talks

  • – Long-Scale Planetary Ultra-Low-Frequency Electromagnetic Wave Structures in F-region of the Spherical Dissipative Ionosphere, by Khatuna Elbakidze (Speaker) at ISAP2007, International Symposium on Antennas and Propagation, 2007, Toki Messe, Niigata, Japan.
  • Ultra Low Frequency Electromagnetic Wave’s dynamics at interaction with local inhomogeneous winds, by Khatuna Elbakidze (Speaker) at UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science "First Results from the International Heliophysical Year 2007, 2008, Sozopol, Bulgaria.
  • Alfven wave generation and mutual transformation into drift waves at interaction with local inhomogeneous shear flows in the Earth Upper Atmosphere, by Khatuna Elbakidze (Speaker) at IAU Symposium 257 – Universal Heliophysical Processes 257, 2008, Greece, Ioannina.
  • Shear flow induced Alfven wave generation and mutual transformation into drift waves and vise versa in the ionosphere, by Khatuna Elbakidze (Speaker) at IAGA (International Association of Geomagnetism and Aeronomy) International Symposium "Space weather and its effects on Spacecraft" , 2008, Cairo, Egypt.

Publications

  • Giorgi Aburjania, Gaetsno Zimbardo, Khatuna Elbakidze, Large-scale zonal flow and magnetic field generation due to drift-Alfven turbulence in ionosphere plasma, Planetary and Space Science Volume 57, Issue 12, October 2009, Pages 1474-1484, Elsevier, 2009.
  • Giorgi Aburjania, Gaetsno Zimbardo, Khatuna Elbakidze, Model of strong stationary vortex turbulence in space plasmas, Nonlin. Processes Geophys., 16, 11–22, 2009, Copernicus, 2009.
  • Gaetsno Zimbardo, Luca Sorriso Valvo, Giorgi Aburjania, Khatuna Elbakidze, Magnetic turbulence in the geospace environment, Space Science Reviews 156(1):89-134, Springer, 2010.