Study On The Solitonic And Chaotic Phenomena In Plasmas

Plasma, which widely exists in the Universe, can often be seen as the 4th fundamental states of matter, the others being solid, liquid and gas, and it al-ways attracts people's attention. Studies on the plasmas have also provided different techniques and technologies for the development of space physics,materials, energy and information. Through the analytic and numeric methods,and via some nonlinear evolution equations, this dissertation will focus on the solitonic and chaotic phenomena in the plasmas, and the emphasis will be paid on the effects of related physical parameters on the soliton and chaos, which will extend the early literatures on the plasmas to some extent. Main research contents of this dissertation can be included as the following five aspects:(1) For the electron-positron-ion (e-p-i) plasma's: Using the bright soli-ton solutions of (2+1)-dimensional Zakharov - Kuznetsov(ZK) equation, we study the characteristics of the electrostatic soliton in an e-p-i plasma; With the existence of two kinds of external forces, i.e., the periodic and exponen-tially decreasing ones, we obtain the electrostatic soliton-like solutions; Via the bright and dark soliton solutions of (3+1)-dimensional Schrodinger equation,the properties of ion-acoustic waves are discussed; Chaotic. motions in the e-p-i plasmas which are effected by the driving force are investigated, as well as the effects of physical parameters and force on the chaos.(2) For the quantum plasmas: the one- and two-soliton solutions of quan-tum ZK and extended quantum ZK equations are obtained; Via such solutions,we respectively explore the characteristics of solitons in the dense quantum magnetoplasma and quantum electron-positron-ion magnetoplasma; Chaotic motions in such two kinds of quantum plasmas perturbed by the driving forces as well as their properties are analyzed.(3) For the dusty plasmas: In virtue of (3+1)-dimensional generalized John-son model and extended ZK equation, we respectively discuss the character-istics of solitons in the unmagnetized dusty plasma and magnetized two-ion-temperature dusty plasma; Using ZK-Burges equation, we investigate the prop-agation of shock-like wave in a magnetized dusty plasma; Different chaotic motions in such three dusty plasmas perturbed by the driving forces are respec-tively observed, including the concrete effects of forces on the chaos.(4) For the Langmuir wave: With the help of Zakharov equations, the mechanism of soliton propagation during the interaction between the high-frequency Langmuir wave and low-frequency ion-acoustic wave in a plasma is investigated; By use of Klein-Gordon-Zakharov equation, the characteristics of two kinds of solitons, i.e., the bright and mixed-type ones, during the interac-tion between the Langmuir wave and ion sound wave in a high-frequency plas-ma are discussed; Considering the periodic driving force, we study the chaotic motions in such two cases and effects of the force on the chaos.