Waves and instabilities due to inhomogeneous Plasma Flows and Formation of nonlinear Structures

Abstract

The effects of the constant and space-dependant flows of plasma species on the linear and nonlinear dynamics of low frequency electrostatic and electromagnetic waves are studied by using fluid theory. The nonlinear structures such as solitons, double layers and vortices produced by plasma flows are studied under local approximation. The theoretical model is applied to space and astrophysical plasmas where the particle velocity distributions exhibit non-Maxwellian behavior, in general. Therefore the nonlinear structures have also been investigated considering kappa, qnonextensive and Cairn's distributions etc. of lighter species. The characteristics of these structures such as the width and amplitude of solitons and double layers are modified in a non-Maxwellian plasma significantly as compared to those when the lighter particles are Maxwellian. The Sagdeev pseudo-potential appraoch has been employed to get the strongly nonlinear dynamics for the formation of solitons and double layers (DLs), while the small amplitude limits are also obtained. Both uniform and sheared flows give rise to instabilities of electrostatic and electromagnetic waves. The effects of non-Maxwellian distributions on the new type of drift wave, which appear even in density homogeneous plasmas and, appear due to sheared flow of electrons and ions in the stationary dust plasmas have been pointed out. The coupling of this mode with Alfvén wave is also investigated and electromagnetic vortices are obtained. Comparison of this research work with initial studies is also presented and theoretical model is applied to Saturn's and Jupiter’s magnetosphere for the sake of illustrations. An analysis of the sheared flow driven instabilities with kinetic approach is also presented and comparison with fluid theory is discussed.