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Title: Electron-acoustic solitary waves in the presence of a suprathermal electron component

Abstract

The nonlinear dynamics of electron-acoustic localized structures in a collisionless and unmagnetized plasma consisting of ''cool'' inertial electrons, ''hot'' electrons having a kappa distribution, and stationary ions is studied. The inertialess hot electron distribution thus has a long-tailed suprathermal (non-Maxwellian) form. A dispersion relation is derived for linear electron-acoustic waves. They show a strong dependence of the charge screening mechanism on excess suprathermality (through {kappa}). A nonlinear pseudopotential technique is employed to investigate the occurrence of stationary-profile solitary waves, focusing on how their characteristics depend on the spectral index {kappa}, and the hot-to-cool electron temperature and density ratios. Only negative polarity solitary waves are found to exist, in a parameter region which becomes narrower as deviation from the Maxwellian (suprathermality) increases, while the soliton amplitude at fixed soliton speed increases. However, for a constant value of the true Mach number, the amplitude decreases for decreasing {kappa}.

Authors:
; ;  [1];  [2]
  1. Centre for Plasma Physics, Department of Physics and Astronomy, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom)
  2. School of Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa)
Publication Date:
OSTI Identifier:
22046892
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 18; Journal Issue: 7; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMPLITUDES; COLLISIONLESS PLASMA; DISPERSION RELATIONS; ELECTRON PLASMA WAVES; ELECTRON TEMPERATURE; ELECTRONS; INDEXES; IONS; MACH NUMBER; NONLINEAR PROBLEMS; PLASMA DENSITY; POTENTIALS; SOLITONS

Citation Formats

Danehkar, Ashkbiz, Saini, Nareshpal Singh, Kourakis, Ioannis, and Hellberg, Manfred A. Electron-acoustic solitary waves in the presence of a suprathermal electron component. United States: N. p., 2011. Web. doi:10.1063/1.3606365.
Danehkar, Ashkbiz, Saini, Nareshpal Singh, Kourakis, Ioannis, & Hellberg, Manfred A. Electron-acoustic solitary waves in the presence of a suprathermal electron component. United States. doi:10.1063/1.3606365.
Danehkar, Ashkbiz, Saini, Nareshpal Singh, Kourakis, Ioannis, and Hellberg, Manfred A. Fri . "Electron-acoustic solitary waves in the presence of a suprathermal electron component". United States. doi:10.1063/1.3606365.
@article{osti_22046892,
title = {Electron-acoustic solitary waves in the presence of a suprathermal electron component},
author = {Danehkar, Ashkbiz and Saini, Nareshpal Singh and Kourakis, Ioannis and Hellberg, Manfred A.},
abstractNote = {The nonlinear dynamics of electron-acoustic localized structures in a collisionless and unmagnetized plasma consisting of ''cool'' inertial electrons, ''hot'' electrons having a kappa distribution, and stationary ions is studied. The inertialess hot electron distribution thus has a long-tailed suprathermal (non-Maxwellian) form. A dispersion relation is derived for linear electron-acoustic waves. They show a strong dependence of the charge screening mechanism on excess suprathermality (through {kappa}). A nonlinear pseudopotential technique is employed to investigate the occurrence of stationary-profile solitary waves, focusing on how their characteristics depend on the spectral index {kappa}, and the hot-to-cool electron temperature and density ratios. Only negative polarity solitary waves are found to exist, in a parameter region which becomes narrower as deviation from the Maxwellian (suprathermality) increases, while the soliton amplitude at fixed soliton speed increases. However, for a constant value of the true Mach number, the amplitude decreases for decreasing {kappa}.},
doi = {10.1063/1.3606365},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 7,
volume = 18,
place = {United States},
year = {2011},
month = {7}
}