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Possibility of generation of large-scale sheared zonal flow and magnetic field by coupled under the typical ionospheric conditions short-scale planetary low-frequency waves is shown. Propagation of coupled internal-gravity-Alfven, Rossby-Khantadze, Rossby-Alfven-Khantadze and collision-less electron skin depth order drift-Alfven waves is revealed and investigated in detail. To describe the nonlinear interaction of such coupled waves with sheared zonal flow the corresponding nonlinear equations are deduced. The instability mechanism is based on the nonlinear parametric triple interaction of the finite amplitude short-scale planetary waves leading to the inverse energy cascade toward the longer wavelengths. It is shown that under such interaction intense sheared magnetic fields can be generated. Appropriate growth rates are discussed in detail.

Numerous ground-based and satellite experiments justify permanent existence of zonal flows in different layers of the Earth’s atmosphere [

Latitudinal inhomogeneity of both the Coriolis parameter and the geomagnetic field, and also caused by the gravitation so called stratification under the ionospheric conditions lead to the coupling of different electromagnetic (EM) planetary waves such as coupled Rosssby-Khantadze (CRK) [

According to the nowadays presentations sheared zonal flows are created by the nonhomogeneous heating of the atmospheric layers by solar radiation. But during the last decade a great amount of publications revealed different nonlinear mechanisms leading to the generation of sheared zonal flow. Namely the excitation of zonal flow based on the triple planetary waves nonlinear parametric instability in the Earth’s ionospheric medium was widely investigated (see [

In the given paper we review the possibility of generation of zonal flow and magnetic field by different coupled EM ULF waves in the weakly ionized Earth’s ionosphere. The local Cartesian system of coordinates (

The generation of large-scale zonal flows and magnetic fields due to small-scale drift-Alfven turbulence in the ionospheric plasma medium is investigated (see details in [

It is shown that in the Earth’s E-layer under the prevalent Hall conductivity due to the latitudinal non-homo- geneity of geomagnetic field, slow and fast waves can couple and form EM CRK waves (see details in [

The basic 2D nonlinear equations describing the dynamics of zonal flow generation and coupled internal-gravity and Alfven wave propagation under the Boussinesq approximation are constructed (see details in [^{−1} and 5 - 50 km is the typical values of the corresponding wavelengths. Dealing with zonal flow excitation, we used the parametric approach allowing one to consider monochromatic primary modes. The investigated sheared zonal flow propagates along the Earth’s parallels. The corresponding velocity is only dependent on the vertical z-coordinate. Excited mean magnetic field is in local vertical straight z-direction; the zonal flow is also sheared in this direction. The maximum growth rate for zonal flow is estimated

Nonlinear dynamics of CRAK EM planetary modes in the ionospheric E-layer is investigated (see details in [

Possibility of the generation of sheared zonal flow and sheared magnetic field in the weakly ionized conductive ionospheric gas is investigated. Propagation of electromagnetic coupled drift-Alfven (CDA), Rossby-Khantadze (CRK), Internal-gravity-Alfven (CIGA), and Rossby-Alfven-Khantadze (CRAK) waves is analyzed. It is shown that owing to the latitudinal nonhomogeneity of the geomagnetic field slow and fast waves can couple and form CRK waves. It is shown that Internal-gravity and Alfven waves can be coupled through the z-component of wavevector. In contrast to CRK and CIGA waves the perturbed magnetic field of other polarization (with x- and y-components) is considered for CRAK and CDA waves. This makes the problem essentially three dimensional. As a result, owing to the existence of the magnetic field perturbations, Alfven waves also became incorporated. Action of these effects leads to the coupled propagation of EM coupled Rossby-Alfven-Khantadze and drift- Alfven modes.

Simplified set of nonlinear equations describing the dynamics of mentioned coupled EM modes is obtained: 1) spatially 2D equations in case of CRK and CIGA and 2) spatially 3D equations in case of CRAK and CDA modes, respectively.

Nonlinear instability of short wavelength turbulence of mentioned CIGA, CRK, CRAK, and CDA EM planetary modes with respect to the excitation of low-frequency and large-scale perturbations of sheared zonal flow and magnetic field is revealed. The nonlinear mechanism of the instability is driven by the advection of vorticity and is based on the parametric excitation of zonal flow by three finite-amplitude coupled modes leading to the inverse energy cascade toward the longer wavelength. The growth rates of the corresponding instability and the conditions for driving them are determined. The possibility of generation of the intense mean magnetic field is shown.

Obtained results can be used to elucidate different laboratory and space experiments.

T. D. Kaladze,Kh. Chargazia,O. Kharshiladze,L. V. Tsamalashvili, (2016) Generation of Zonal Flow and Magnetic Field by Planetary Waves in the Earth’s Ionosphere. Journal of Applied Mathematics and Physics,04,487-491. doi: 10.4236/jamp.2016.42054