الفهرس | Only 14 pages are availabe for public view |
Abstract A theoretical study is presented on the nonlinear self modulation of low frequency electrostatic dust acoustic (DA) waves propagating in a strongly coupled dusty plasma (SCDP) in the hydrodynamic regime. Using the derivative expansion perturbation method, the basic equations are reduced to a nonlinear Schr ̈ dinger type (NLST) equation describing the modulated dust acoustic waves. The modulation (in) stability (MI) and the dependence of the system physical parameters (angular frequency and group velocity) on the polarization force variation have been examined. Moreover, the extended Poincar ́ -Lighthill Kuo (PLK) technique is used to investigate the head-on collision (HoC) between two DA dark solitons. The analytical phase shifts and the trajectories of these dark solitons after the collision are derived. The numerical calculations illustrate that the polarization effect has a strong influence on the nature of the phase shifts and the trajectories of the two DA dark solitons after collision. Futhermore, we investigated the MI of DAWs in a strongly coupled dust plasma in the kinetic regime considering the variable dust charge. Employing the derivative expansion perturbation technique, NLST equation, which governs the MI of DAW, is obtained. Also, the characteristics of the HoC between two dark solitons have been investigated theoretically in this regime. Using the extended PLK technique, the analytical phase shifts after the HoC of two dark solitons occurs are derived. It is found that the presence of the viscosity and the dust charge variation as well as variation of relaxation time significantly modify the domain of the MI and the HoC characteristics. The present study is helpful in investigating nonlinear interaction and the HoC of two DA solitary waves observed in recent dusty plasma experiments. |