Self-organization of ULF electromagnetic wave structures in the shear flow driven dissipative ionosphere
G. Aburjania1,2, K. Chargazia1,2, O. Kharshiladze2, and G. Zimbardo31I. Vekua Institute of Applied Mathematics, Tbilisi State University, 2 University str., 0143 Tbilisi, Georgia 2M. Nodia Institute of Geophysics, Tbilisi State University, 1 Aleqsidze str., 0193 Tbilisi, Georgia 3Physics Department, University of Calabria, Ponte P. Bucci, Cubo 31 C, 87036 Rende, Italy
Received: 18 Jul 2014 – Accepted for review: 28 Jul 2014 – Discussion started: 26 Aug 2014
Abstract. This work is devoted to investigation of nonlinear dynamics of planetary electromagnetic (EM) ultra-low-frequency wave (ULFW) structures in the rotating dissipative ionosphere in the presence of inhomogeneous zonal wind (shear flow). Planetary EM ULFW appears as a result of interaction of the ionospheric medium with the spatially inhomogeneous geomagnetic field. The shear flow driven wave perturbations effectively extract energy of the shear flow increasing own amplitude and energy. These perturbations undergo self organization in the form of the nonlinear solitary vortex structures due to nonlinear twisting of the perturbation's front. Depending on the features of the velocity profiles of the shear flows the nonlinear vortex structures can be either monopole vortices, or dipole vortex, or vortex streets and vortex chains. From analytical calculation and plots we note that the formation of stationary nonlinear vortex structure requires some threshold value of translation velocity for both non-dissipation and dissipation complex ionospheric plasma. The space and time attenuation specification of the vortices is studied. The characteristic time of vortex longevity in dissipative ionosphere is estimated. The long-lived vortices transfer the trapped medium particles, energy and heat. Thus they represent structural elements of turbulence in the ionosphere.
Aburjania, G., Chargazia, K., Kharshiladze, O., and Zimbardo, G.: Self-organization of ULF electromagnetic wave structures in the shear flow driven dissipative ionosphere, Nonlin. Processes Geophys. Discuss., 1, 1431-1464, doi:10.5194/npgd-1-1431-2014, 2014.