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Title: Generation mechanism for electron acoustic solitary waves

Abstract

Nonlinear electron acoustic solitary waves (EASWs) are studied in a collisionless and unmagnetized plasma consisting of cold background electrons, cold beam electrons, and two different temperature ion species. Using pseudopotential analysis, the properties of arbitrary amplitude EASWs are investigated. The present model supports compressive as well as rarefactive electron acoustic solitary structures. Furthermore, there is an interesting possibility of the coexistence of compressive and rarefactive solitary structures in a specific plasma parameter range. The application of our results in interpreting the salient features of the broadband electrostatic noise in the plasma sheet boundary layer is discussed.

Authors:
; ; ; ; ;  [1];  [2];  [3]
  1. Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai-410 218 (India)
  2. (Ethiopia)
  3. (Belgium) and School of Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa)
Publication Date:
OSTI Identifier:
20974975
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2732176; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AMPLITUDES; BEAM-PLASMA SYSTEMS; BOUNDARY LAYERS; ELECTRON BEAMS; ELECTRONS; ION TEMPERATURE; NOISE; NONLINEAR PROBLEMS; PLASMA; PLASMA SHEET; PLASMA WAVES; POTENTIALS; SOLITONS

Citation Formats

Kakad, A. P., Singh, S. V., Reddy, R. V., Lakhina, G. S., Tagare, S. G., Verheest, F., Department of Mathematics, Addis Ababa University, Addis Ababa, and Sterrenkundig Observatorium, Universiteit Gent, Krijglaan 281, B-9000 Gent. Generation mechanism for electron acoustic solitary waves. United States: N. p., 2007. Web. doi:10.1063/1.2732176.
Kakad, A. P., Singh, S. V., Reddy, R. V., Lakhina, G. S., Tagare, S. G., Verheest, F., Department of Mathematics, Addis Ababa University, Addis Ababa, & Sterrenkundig Observatorium, Universiteit Gent, Krijglaan 281, B-9000 Gent. Generation mechanism for electron acoustic solitary waves. United States. doi:10.1063/1.2732176.
Kakad, A. P., Singh, S. V., Reddy, R. V., Lakhina, G. S., Tagare, S. G., Verheest, F., Department of Mathematics, Addis Ababa University, Addis Ababa, and Sterrenkundig Observatorium, Universiteit Gent, Krijglaan 281, B-9000 Gent. Tue . "Generation mechanism for electron acoustic solitary waves". United States. doi:10.1063/1.2732176.
@article{osti_20974975,
title = {Generation mechanism for electron acoustic solitary waves},
author = {Kakad, A. P. and Singh, S. V. and Reddy, R. V. and Lakhina, G. S. and Tagare, S. G. and Verheest, F. and Department of Mathematics, Addis Ababa University, Addis Ababa and Sterrenkundig Observatorium, Universiteit Gent, Krijglaan 281, B-9000 Gent},
abstractNote = {Nonlinear electron acoustic solitary waves (EASWs) are studied in a collisionless and unmagnetized plasma consisting of cold background electrons, cold beam electrons, and two different temperature ion species. Using pseudopotential analysis, the properties of arbitrary amplitude EASWs are investigated. The present model supports compressive as well as rarefactive electron acoustic solitary structures. Furthermore, there is an interesting possibility of the coexistence of compressive and rarefactive solitary structures in a specific plasma parameter range. The application of our results in interpreting the salient features of the broadband electrostatic noise in the plasma sheet boundary layer is discussed.},
doi = {10.1063/1.2732176},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • The nonlinear wave structure of small-amplitude electron-acoustic solitary waves (EASWs) is investigated in a four-component plasma consisting of cold electron fluid, hot electrons obeying vortex-like distribution traversed by a warm electron beam and stationary ions. The streaming velocity of the beam, u{sub o}, plays the dominant role in determining the roots of the linear dispersion relation associated with the system. Using the reductive perturbation theory, the basic set of equations is reduced to a modified Korteweg-de Vries (mKdV) equation. With the inclusion of higher-order nonlinearity, a linear inhomogeneous mKdV type equation with fifth-order dispersion term is derived and the higher-ordermore » solution is obtained using a renormalization method. However, both mKdV and mKdV-type solutions present a positive potential, which corresponds to a hole (hump) in the cold (hot) electron number density. The mKdV-type solution has a smaller energy amplitude and a wider width than that of mKdV solution. The dependence of the energy amplitude, the width, and the velocity on the system parameters is investigated. The findings of this investigation are used to interpret the electrostatic solitary waves observed by the Geotail spacecraft in the plasma sheet boundary layer of the Earth's magnetosphere.« less
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  • The basic features of obliquely propagating electron-acoustic (EA) solitary waves and their multidimensional instability in a magnetized plasma containing cold electrons, hot electrons obeying a vortexlike distribution, and stationary ions have been theoretically investigated by the reductive perturbation method and small-k perturbation expansion technique. The combined effects of external magnetic field (obliqueness) and trapped electron distribution, which are found to significantly modify the basic properties (amplitude and width) of small but finite-amplitude EA solitary waves, are explicitly examined. It is also found that the instability criterion and the growth rate are significantly modified by the external magnetic field and themore » propagation directions of both the nonlinear waves and their perturbation modes. The implications of our results in space plasmas are briefly discussed.« less
  • The electron acoustic solitary waves are studied in unmagnetized two population electron quantum plasmas. The quantum hydrodynamic model is employed with the Sagdeev potential approach to describe the arbitrary amplitude electron acoustic waves in a two electron population dense Fermi plasma. It is found that hot electron density hump structures are formed in the subsonic region in such type of quantum plasmas. The wave amplitude as well as the width of the soliton are increased with the increase of percentage presence of cold (thinly populated) electrons in a multicomponent quantum plasma. It is found that an increase in quantum diffractionmore » parameter broadens the nonlinear structure. Furthermore, the amplitude of the nonlinear electron acoustic wave is found to increase with the decrease in Mach number. The numerical results are also presented to understand the formation of solitons in two electron population Fermi plasmas.« less
  • 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 negativemore » 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}.« less