الفهرس 
Basic considerationsOnly 14 pages are availabe for public view
 |  | from | 163 |  |  |
| | | from | 163 | | |
Abstract
In this thesis, we study some nonlinear partial differential equations (NLPDEs) in plasma physics. Some physical models described by some NLPDEs are studied. The exact solutions for these models and related physical quantities by using several methods are obtained. In introduction, we give quick hint for the importance of Magnetohydrodynamics (MHD) and plasma physics with its applications. In chapter one, we considered a background for the material used in this thesis in this chapter. It cover the fundamental concepts of known results concerning our objects to make this thesis somewhat self contained. In chapter two, we study a family of nonlinear force-free magnetic fields (FFMFs) by using F-expansion Method. The FFMFs are governed by an elliptic second order nonlinear PDE for the poloidal magnetic flux function coupled with an algebraic Bernoulli equation. We construct explicit exact solutions by JEFs of FFMFs for constant and non-constant Mach number flows. In chapter three, nonlinear waves in warm dusty plasmas with variable dust charge, two-temperature ions, and nonthermal electrons are studied. The reductive perturbation method has been employed to drive Kadomtsev–Petviashivili (KP) and modified (KP) equations. We find several exact solutions for this equations by using Elliptic expansion function method. In chapter four, Exact solutions for two-dimensional ideal magnetohydrodynamic plasma with steady incompressible flow described by Liouvelle, double sinh, combined sinh-cosh, and combined double sinh-cosh Poisson equations are derived. Several classes of exact solutions for nonlinear cases are obtained by using generalized tanh method. In chapter five, We discussed the derivation of Sagdeev potential, as a results of which, could be analyzed to predict the existence of various features of localized solitons in various configurations of plasmas. We find exact wave solution of the Korteweg-de Vries (KdV) equation, Schamel equation and generalized Schamel equation by using Jacobi elliptic function expansion method.
Key words:
plasma physics, nonlinear partial differential equations, Exact solutions, Magnetohydrodynamics, force-free magnetic fields, F-expansion Method, perturbation method, dusty plasma, the Korteweg-de Vries (KdV) , Jacobi elliptic function method, Kadomtsev–Petviashivili (KP).