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

R. Sabry, W.M. Moslem, P.K. Shukla

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Abstract

Properties of fully nonlinear ion-acoustic solitary waves in a plasma with positive-negative ions and nonthermal electrons are investigated. For this purpose, the hydrodynamic equations for the positive-negative ions, nonthermal electron density distribution, and the Poisson equation are used to derive the energy integral equation with a new Sagdeev potential. The latter is analyzed to examine the existence regions of the solitary pulses. It is found that the solitary excitations strongly depend on the mass and density ratios of the positive and negative ions as well as the nonthermal electron parameter. Numerical solution of the energy integral equation clears that both positive and negative potentials exist together. It is found that faster solitary pulses are taller and narrower. Furthermore, increasing the electron nonthermality parameter (negative-to-positive ions density ratio) decreases (increases) the localized excitation amplitude but increases (decreases) the pulse width. 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- and F-regions of the Earth's ionosphere. This investigation should be helpful in understanding the salient features of the fully nonlinear ion-acoustic solitary waves in space and in laboratory plasmas where two distinct groups of ions and non-Boltzmann distributed electrons are present.
Original languageEnglish
Pages (from-to)032302-1
Number of pages32301
JournalPhysics of Plasmas
Volume16
Issue number3
DOIs
Publication statusPublished - Mar 2009

Keywords

  • D-region
  • electron density
  • F-region
  • hydrodynamics
  • integral equations
  • plasma density
  • plasma ion acoustic waves
  • plasma solitons
  • Poisson equation

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