Ion-Acoustic Rogue Waves in Multi-ion Plasmas*

Abstract

The basic properties of nonlinear ion-acoustic (IA) waves (IAWs), particularly finite amplitude IA rogue waves (IARWs) in a plasma medium (containing pair ions, iso-thermal positrons and non-thermal electrons) are theoretically investigated by deriving the nonlinear Schrödinger equation (NLSE). The criteria for the modulational instability of IAWs, and the basic features of finite amplitude IARWs are identified. The modulationally stable and unstable regions are determined by the sign of the ratio of the dispersive coefficient to the nonlinear coefficient of NLSE. The latter is analyzed to obtain the region for the existence of the IARWs, which corresponds to the unstable region. The shape of the profile of the rogue waves depends on the non-thermal parameter α and the ratio of electron temperature to positron temperature. It is found that the increase in the value of the non-thermal parameter enhances both the amplitude and width of IARWs, and that the enhancement of positron (electron) temperature reduces (enhances) the amplitude and width of IARWs. It is worth to mention that our present investigation may be useful for understanding the salient features of IARWs in space (viz., upper region of Titan's atmosphere, cometary comae, and Earth's ionosphere, etc.) and laboratory (viz., plasma processing reactor and neutral beam sources, etc.) plasmas.

Dust-ion-acoustic rogue waves in presence of non-extensive non-thermal electrons

“…This figure clearly indicates that the increase in the value of α does not only cause to increase the amplitude of the DIARWs associated DIAWs in the modulationally unstable domain (i.e., P/Q > 0) but also cause to increase the width of the DIARWs associated DIAWs in the modulationally unstable domain (i.e., P/Q > 0). The physics of this result is that increasing α causes to increase the nonlinearity of the plasma medium as well as the amplitude and width of the DIARWs, and this result is a nice agreement with the result of El-Labany et al [34] and Hassan et al [35].…”

“…Rogue wave (RW) [27,28,29], which governs by the ra-tional solution of the standard nonlinear Schrödinger equation (NLSE) [27,28,29,30,31,32,33,34,35,36] in a dispersive medium, was firstly observed in the ocean. It is a rare, shortlived, and high-energy event with amplitude much higher than the average wave crests around it [27].…”

Dust-ion-acoustic shock waves in magnetized plasma having super-thermal electrons

“…To derive the Burgers' equation for the DIASHWs propagating in a magnetized plasma, we are going to employ reductive perturbation method [46]. First we introduce the stretched coordinates [41,47]…”

Dust-acoustic rogue waves in non-thermal plasmas

“…The plot of P/Q against k yields stable and unstable parametric regimes of the DAWs. The point, at which the transition of P/Q curve intersect with k-axis, is known as threshold or critical wave number k (= k c ) [18,19,20,21,22,23,24,25]. The governing equation for highly energetic DARWs in the modulationally unstable parametric regime (P/Q > 0) can be written as [26,27,28,29,30]…”