Interaction Phenomena of Nonlinear Waves in Unmagnetized Plasmas

Abstract

This dissertation is concerned with the study of interaction phenomena of nonlinear waves in unmagnetized plasmas. The plasma system considered is fully ionized, collisionless and homogeneous and/or inhomogeneous that contains multi-component plasma species under different situations. To investigate the physical issues of the interaction phenomena of nonlinear waves the nonlinear evolution equations are derived. The extended Poincaré-Lighthill-kue (ePLK) method is used to derive the nonlinear evolution equations. The interaction phenomena pertaining to plasma parameters on the production of ion-acoustic solitary waves, ion-acoustic shock waves and rogue waves and their consequences on phase shifts and amplitudes are investigated in different plasma situation. The interaction processes among the waves (such as ion-acoustic solitary waves, ion-acoustic shock waves) for single and multi-soliton plasmas are also studied considering the analytical solutions to the nonlinear evolution equations under some assumptions to discuss the characteristic of the waves in the plasmas that are observed in astrophysical, space and laboratory plasmas. In chapter one, some important physical terms that are relevant to the plasma phenomena are briefly discussed. Chapter two discusses the interaction phenomena of ion-acoustic multi-solition and the production of rogue waves in an unmagnetized plasmas composing non-relativistic as well as relativistic degenerate electrons and positrons, and inertial non-relativistic helium ions. The interaction phenomena are investigated by deriving two-sided Korteweg-de Vries (KdV) equations with their corresponding phase shifts employing extended Poicaré-Lighthill-Kuo (ePLK) method and to study the properties of rogue waves the nonlinear Schrödinger equation (NLSE) is obtained from the modified KdV (mKdV) equation.-------