Journal of Plasma Physics

Table of Contents - 2007 - Volume 73, Issue 01  

Papers

Rossby-wave driven zonal flows in the ionospheric E-layer

T. D. KALADZEa1a2, D. J. WUa1, O. A. POKHOTELOVa3a4, R. Z. SAGDEEVa5, L. STENFLOa6 and P. K. SHUKLAa7

a1 Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, 210008, People's Republic of China

a2 I. Vekua Institute of Applied Mathematics, Tbilisi State University, 2 University Street, 0143 Tbilisi, Georgia

a3 Automatic Control and Systems Engineering, University of Sheffield, Sheffield, UK

a4 Institute of Physics of the Earth, 123995 Moscow, 10 B. Gruzinskaya Street, Russia

a5 Department of Physics, University of Maryland, College Park, MD 20740, USA

a6 Department of Physics, Umeå University SE-90 187 Umeå, Sweden

a7 Institut für Theoretische Physik IV, Ruhr–Universität Bochum, D-44780 Bochum, Germany

Abstract.

A novel mechanism for the generation of large-scale zonal flows by small-scale Rossby waves in the Earth's ionospheric E-layer is considered. The generation mechanism is based on the parametric excitation of convective cells by finite amplitude magnetized Rossby waves. To describe this process a generalized Charney equation containing both vector and scalar (Korteweg–de Vries type) nonlinearities is used. The magnetized Rossby waves are supposed to have arbitrary wavelengths (as compared with the Rossby radius). A set of coupled equations describing the nonlinear interaction of magnetized Rossby waves and zonal flows is obtained. The generation of zonal flows is due to the Reynolds stresses produced by finite amplitude magnetized Rossby waves. It is found that the wave vector of the fastest growing mode is perpendicular to that of the magnetized Rossby pump wave. Explicit expression for the maximum growth rate as well as for the optimal spatial dimensions of the zonal flows are obtained. A comparison with existing results is carried out. The present theory can be used for the interpretation of the observations of Rossby-type waves in the Earth's ionosphere.

(Received November 18 2005)