Start Date: 2003-01-01 End Date: 2005-01-01
Fundametal theoretical investigation of the propagation of large-scale planetary waves( with wavelength 1000 km or larger) and associated nonlinear solitary vortical structures in the Earth's ionosphere taking into account the interaction of the induction electric current and the spatially inhomogeneous geomagnetic field is the major goal of the presented project. Based on the developed fluid dynamics and MHD equations, the research is accomplished by means of both analytical and numerical methods. It is shown that permanently acting global factors-the spatial inhomogeneity and curvature of the geomagnetic field are the generation sources of the planetary ultra-low frequency (ULF) electromagnetic waves.
The shallow water theory is developed for perturbations propagating in the ionospheric E-layer .For such weakly-ionized plasma, a nonlinear generalized Charney-Obukhov ( GChO) equation for magnetized Rossby waves is derived.These waves are produced by the dynamo electric field and represents the ionospheric generalization of tropospheric Rossby waves in a rotating atmosphere by the spatially inhomogenous geomagnetic field.It is shown that the mechanism of a self-organisation of solitary vortical structures is the result of the mutual compensation of wave dispersion and interaction through the scalar and Poisson bracket convective nonlinearities in the wave equation. As a result , the solitary structures are anisotropic , containing a circular vortex superimposed on a dipole perturbation. Stationary nonlinear solutions in case of synoptic-scale perturbations are analized analytically. The instability of the magnetized Rossby waves in the limit of ageostrophic velocities is revealed.The new implicit difference schemes of the first and second accuracy used to obtain numerical solutions of the GCho equation are constructed. The new physical model of generation of experimentally observed large-scale vortical electric fields in the ionospheric E and F-layers is eleborated. It is established that in the ionospheric E and F-layers so called fast and slow ULF electromagnetic planetary waves may be excited.
Obtained resultes are original and in good accordance with the existing ionospheric observations. They stimulate new experimental investigations. On the basis of the obtained results , a new method of definition of both ionospheric particles number densities and local winds velocities is suggested.