The Study Of Dusty Plasma Parameters On The Structures Of Dust-Acoustic Solitary Waves

In this thesis, an unmagnetized, collisionless dusty plasma which consisted of extremely massive, highly negatively charged dust particles, ions and electrons are studied. Considering the effects of hot dust fluid with non-thermal ions and variable dust charge, we study the self-consisted system parameters on the structures of the dust-acoustic solitary waves by reductive perturbation methods.First, we obtained a KdV equation that governs the behavior of small but infinite amplitude dust-acoustic waves. the results shows that: as the fast ions numberα=0, ie., the ions number density reduces to the Boltzmann ion distribution, the solitary waves are all rarefactive, which are in good agreement with Ref. [81]. as the fast ions increases, the compressive waves can also exist in some special regions. Both the rarefactive and compressive waves can be determined by plasma parameters including the temperatures of dust fluid, ion and electron, as well as the non-thermal ions, and the number densities of dust particle , ion and election, etc.Second, a modified KdV (mKdV) equation which describes the dust-acoustic solitons in this system is derived. The effects of dusty plasma parameters on the dust-acoustic solitary waves have been studied theoretically . It is found that the soliton structures is decided by the dusty plasma parameters. The solitons only exist in some regions as these parameters are specially chosen. Furthermore, the properties of the dust-acoustic solitary waves can be significantly influenced by the dust plasma parameters, such as the temperature , the number densities, and the charge variation of dust particle, the fast ions , the ion number densities , the ion temperature , the electron number densities and the electron temperature , etc.