Interpretation of localized surface nano-structures

Recent experiment was done to create surface nano-structures by extrusion of slow highly charged ions with LiNbO_3 single crystal. In this paper, we suggest a mechanism based on plasma expansion approach to explain the formation of the surface nano-structures. Furthermore, the effects of the physical parameters of the non-Maxwellian plasma on the created structures are examined

Three-Dimensional Rogue Waves in Earth’s Ionosphere

The modulational instability of ion-acoustic waves (IAWs) in a four-component magneto-plasma system consisting of positive–negative ions fluids and non-Maxwellian (r,q) distributed electrons and positrons, is investigated. The basic system of fluid equations is reduced to a three-dimensional (3D) nonlinear Schrödinger Equation (NLS). The domains of the IAWs stability are determined and are found to be strongly affected by electrons and positrons spectral parameters r and q and temperature ratio Tp/Te (Tp and Te are positrons and electrons temperatures, respectively). The existence domains, where we can observe the ion-acoustic rogue waves (IARWs) are determined. The basic features of IARWs are analyzed numerically against the distribution parameters and the other system physical parameters as Tp/Te and the external magnetic field strength. Moreover, a comparison between the first- and second-order rogue waves solution is presented. Our results show that the nonlinearity of the system increases by increasing the values of the non-Maxwellian parameters and the physical parameters of the system. This means that the system gains more energy by increasing r, q, Tp, and the external magnetic field through the cyclotron frequency ωci. Finally, our theoretical model displays the effect of the non-Maxwellian particles on the MI of the IAWs and RWs and its importance in D–F regions of Earth’s ionosphere through (H+,O2−) and (H+,H−) electronegative plasmas

Shock waves in magnetized electronegative plasma with nonextensive electrons

The nonlinear properties of ion acoustic shock waves in a magnetized electronegative plasma with nonextensive electrons and stationary dust grains are studied. The reductive perturbation technique is applied to derive the Zakharov–Kuznetsov Burgers (ZKB) equation. The Tanh method is used to obtain the shock wave solution. The present model is applied to four different electronegative plasma media which are found in space plasma, e.g. (H+, H−) plasma and (H+, ${\mathrm{O}}_2^{-}$) plasma, and laboratory experiments, e.g. (Xe+, ${\mathrm{SF}}_6^{-}$) plasma and (Ar+, ${\mathrm{O}}_2^{-}$) plasma. It is found that the concentration of negative ions and the electron nonextensive parameter have important effects on the features of the propagated ion acoustic shock waves