الفهرس 
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Abstract
The aim of this study is to reveal some of the silent properties of the electronegative plasmas, so we have considered an unmagnetized collisionless multicomponent dusty plasma consisting of the Boltzmann distributed electrons, mobile positive and negative ions. By employing the set of the fluid equations that describe the system containing a test charge density, we calculate the electrostatic potential for the test charge moving with a constant speed along the z-axis. Further, the Debye screening and wake potentials are obtained in the presence of mobile negative and positive ions. It is worth mentioning here that the ion acoustic speed and oscillatory wake potential are significantly modified due to the presence of negative ions. The results should be useful in the context of charged particle repulsion and attraction in microelectronic plasmas and in polar mesosphere. After that, it is shown that the three-dimensional cylindrical Kadomtsev-Petviashvili (CKP) and the extended cylindrical Kadomtsev-Petviashvili (ECKP) equations can describe the propagation of nonplanar dust ion-acoustic excitations in a dusty plasma composed of positive ions, negative ions, stationary dust particles, as well as trapped electrons or a small percentage of trapped electrons. It is found that the solution of the CKP equation supports only solitary pulses, while the ECKP equation describes the propagation of both solitary and shock excitations. The effects of physical parameters, namely negative ions density, dust grains density, positive-to-negative mass ratio, direction cosine of the wave propagation on the pulses profile are examined. Furthermore, the existence regions of either localized or shock pulses are investigated. The relevance of nonlinear structures in the Earth’s ionosphere and plasma experiment is discussed. Moreover, rogue wave in a collisionless, unmagnetized electronegative plasma is investigated. For this purpose, the basic set of fluid equations is reduced to the Korteweg-de Vries (KdV) equation. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency then the KdV equation is also used to study the nonlinear evolution of modulationally unstable modified ion-acoustic wavepackets through the derivation of the nonlinear Schrödinger (NLS) equation. In order to show that the characteristics of the rogue wave is influenced by the plasma parameters, the relevant numerical analysis of the NLS equation is presented. The relevance of our investigation to the Titan’s atmosphere is also discussed.