New mechanism for wavy amplification and mutual transformation in the ionosphere with inhomogeneous zonal winds
|1Aburjania, GD, 2Lominadze, JG, 1Khantadze, AG, 1Kharshiladze, OA |
1Tbilisi State University, Tbilisi, Georgia
2Georgian Space Agency, Tbilisi, Georgia
|Kosm. nauka tehnol. 2006, 12 ;(1):029-048|
|Publication Language: Russian|
The generation and further dynamics of planetary magnetized Rossby waves and inertia waves are investigated in a rotating dissipative ionosphere in the presence of a smooth inhomo-geneous zonal wind (shear flow). Magnetized Rossby waves appear as a result of the interaction of the medium with the spatially inhomogeneous geomagnetic field and are an ionospheric manifestation of usual tropospheric Rossby waves. An effective linear mechanism responsible for the intensification and mutual transformation of Rossby and inertia waves is found. In the case of shear flows, the eigen functions of the problem are non-orthogonal and can hardly be studied by the canonical modal approach. Hence it becomes necessary to use the so-called non-modal mathematical analysis which has been actively developed in recent years. The non-modal approach shows that the transformation of wave disturbances in shear flows is due to the nonorthogonality of eigen functions of the problem in the conditions of linear dynamics. Thus there arise a new degree of freedom and a new way for the evolution of disturbances in the medium. Using the numerical modeling, we illustrate the peculiar features of the interaction of waves with the background flow, as well as the mutual transformation of wave disturbances in the D-, E- and .F-regions of the ionosphere. It is established that the presence of a geomagnetic field, Hall and Pedersen currents in the ionospheric medium improves the interaction and mutual energy exchange between waves and a shear flow.
|Keywords: ionosphere, waves, zonal wind|
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