Envelope ion-acoustic solitary waves in a plasma with positive-negative ions and nonthermal electrons

Abstract

Modulation instability of ion-acoustic waves is investigated in a plasma composed of positive and negative ions as well as nonthermal electrons. For this purpose, a linear dispersion relation and a nonlinear Schrödinger equation are derived. The latter admits localized envelope solitary wave solutions of bright-(pulses) and dark-(holes, voids) type. The envelope soliton depends on the intrinsic plasma parameters. It is found that modulation instability of ion-acoustic waves is significantly affected by the presence of nonthermal electrons. The present model is used to investigate the solitary excitations in the (H+,O2−) and (H+,H−) plasmas, where they are presented in the D-region and F-region of the Earth’s ionosphere. The findings of this investigation should be useful in understanding the stable electrostatic wave packet acceleration mechanisms in positive-negative ion plasmas, and also enhance our knowledge on the occurrence of instability associated to the propagation of the envelope ion-acoustic solitary waves in space and in laboratory plasmas where two distinct groups of ions and non-Boltzmann distributed electrons are present.

General formulation for acoustic solitons in three-component nonthermal plasmas

“…Both distributions have been found to exist in space plasma environments [15][16][17][18][19][20] and applied to the study of certain types of acoustic solitons. [21][22][23] Observational evidences for electrostatic acoustic solitons in the space and laboratory are overwhelming [24][25][26][27][28][29] and the identification of various types of solitons is usually based on standard models assuming Maxwellian distribution. It is important to incorporate more realistic non-Maxwellian distribution in the model calculations and to examine how the characteristics of acoustic solitons such as the polarity of electric potential as well as the number density profile may depend on the distribution functions.…”

Rogue waves in multi‐pair plasma medium

“…The results from this investigation can be summarized as follows: we hope that the results of this theoretical investigation may be helpful in understanding the MI of IAWs and generation of IARWs in laboratory plasmas, viz., PI fullerene (C + , C − ) [4] or in the space plasma, viz., D-region (H + , O − 2 ) and F-region (H + , H − ) of the Earth's ionosphere, [3] Titan's atmosphere, [2] etc. The evolution of the IAWs is governed by the standard NLSE, and the non-linear P and the dispersive Q coefficients represent the stable/unstable domain of the IAWs in presence of the external perturbation.…”

“…The painstaking observational results support the existence of multi-pair plasmas (MPPs) not only in space environments, viz., cometary comae, [1] chromosphere, upper regions of Titan's atmosphere, [2] solar wind, and D-region (H + , O − 2 ) and F-region (H + , H − ) of the Earth's ionosphere [3] but also in laboratory situations, viz., fullerene (C + , C − ), [4] plasma processing reactors, [5] neutral beam sources, [6] etc. Plasma physicists solely deal with the wave dynamics, basically of ion acoustic (IA) waves (IAWs) in which the restoring force is provided by thermal pressure of the electrons and positrons and the moment of inertia is provided by the pair-ion (PI) mass density [7][8][9][10][11] in the PI plasma medium (PIPM).…”

“…The field of MI and RWs has been considered one of the highly interdisciplinary areas of research involving plasma physics, [12] oceanography, [28] Bose-Einstein condensation, [29] optics, [30] superfluid helium, [31] and even finance [32] A number of authors have theoretically studied different criteria of MI and RWs in many PIPM [3,12,33] and confirmed them in laboratory experiments. Elwakil et al [3] analysed the effects of non-thermal electrons on MI conditions of IAWs and observed that electron non-thermality reduces the critical wave number (k c ) in PIPM. Sharma and Bailung [35] have also experimentally found peregrine soliton in a multi-component plasma with a critical density of negative ions.…”

Nonplanar dust ion-acoustic solitary and shock excitations in electronegative plasmas with trapped electrons

“…Barkan et al (1996) observed the DIAWs experimentally. Furthermore, many efforts have been made to understand the properties of linear and nonlinear DIAWs in dusty plasmas (see e.g., Popel and Yu 1995;Nejoh 1997;El-Labany et al 2003;Ali et al 2008aAli et al , 2008bSayed et al 2008;Mamun et al 2009aMamun et al , 2009bElwakil et al 2010;ElLabany et al 2011aElLabany et al , 2011b.…”