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Title: Nonlinear propagation of modulated ion-acoustic plasma waves in the presence of an electron beam

Abstract

Theoretical and numerical studies are presented of the amplitude modulation of ion-acoustic waves (IAWs) in a plasma consisting of warm ions, Maxwellian electrons, and a cold electron beam. Perturbations parallel to the carrier IAW propagation direction have been investigated. The existence of four distinct linear ion acoustic modes is shown, each of which possesses a different behavior from the modulational stability point of view. The stability analysis, based on a nonlinear Schroedinger equation (NLSE) reveals that the IAW may become unstable. The stability criteria depend on the IAW carrier wave number, and also on the ion temperature, the beam velocity and the beam electron density. Furthermore, the occurrence of localized envelope structures (solitons) is investigated, from first principles. The numerical analysis shows that the two first modes (essentially IAWs, modified due to the beam) present a complex behavior, essentially characterized by modulational stability for large wavelengths and instability for shorter ones. Dark-type envelope excitations (voids, holes) occur in the former case, while bright-type ones (pulses) appear in the latter. The latter two modes are characterized by an intrinsic instability, as the frequency develops a finite imaginary part for small ionic temperature values. At intermediate temperatures, both bright- and dark-type excitationsmore » may exist, although the numerical landscape is intertwined between stability and instability regions.« less

Authors:
; ; ;  [1];  [2];  [3]
  1. Azarbaijan University of Tarbiat Moallem, Faculty of Science, Department of Physics, 51745-406, Tabriz (Iran, Islamic Republic of)
  2. (Germany)
  3. (Iran, Islamic Republic of)
Publication Date:
OSTI Identifier:
20782733
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 4; Other Information: DOI: 10.1063/1.2182928; (c) 2006 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; DISTURBANCES; ELECTRON BEAMS; ELECTRON DENSITY; ELECTRON TEMPERATURE; ELECTRONS; EXCITATION; ION ACOUSTIC WAVES; ION TEMPERATURE; IONS; MODULATION; NONLINEAR PROBLEMS; NUMERICAL ANALYSIS; PLASMA; PLASMA DENSITY; PLASMA INSTABILITY; PULSES; RADIATION TRANSPORT; SCHROEDINGER EQUATION; SOLITONS; STABILITY

Citation Formats

Esfandyari-Kalejahi, A., Kourakis, I., Dasmalchi, B., Sayarizadeh, M., Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum, and Azarbaijan University of Tarbiat Moallem, Faculty of Science, Department of Physics, 51745-406, Tabriz. Nonlinear propagation of modulated ion-acoustic plasma waves in the presence of an electron beam. United States: N. p., 2006. Web. doi:10.1063/1.2182928.
Esfandyari-Kalejahi, A., Kourakis, I., Dasmalchi, B., Sayarizadeh, M., Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum, & Azarbaijan University of Tarbiat Moallem, Faculty of Science, Department of Physics, 51745-406, Tabriz. Nonlinear propagation of modulated ion-acoustic plasma waves in the presence of an electron beam. United States. doi:10.1063/1.2182928.
Esfandyari-Kalejahi, A., Kourakis, I., Dasmalchi, B., Sayarizadeh, M., Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum, and Azarbaijan University of Tarbiat Moallem, Faculty of Science, Department of Physics, 51745-406, Tabriz. Sat . "Nonlinear propagation of modulated ion-acoustic plasma waves in the presence of an electron beam". United States. doi:10.1063/1.2182928.
@article{osti_20782733,
title = {Nonlinear propagation of modulated ion-acoustic plasma waves in the presence of an electron beam},
author = {Esfandyari-Kalejahi, A. and Kourakis, I. and Dasmalchi, B. and Sayarizadeh, M. and Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum and Azarbaijan University of Tarbiat Moallem, Faculty of Science, Department of Physics, 51745-406, Tabriz},
abstractNote = {Theoretical and numerical studies are presented of the amplitude modulation of ion-acoustic waves (IAWs) in a plasma consisting of warm ions, Maxwellian electrons, and a cold electron beam. Perturbations parallel to the carrier IAW propagation direction have been investigated. The existence of four distinct linear ion acoustic modes is shown, each of which possesses a different behavior from the modulational stability point of view. The stability analysis, based on a nonlinear Schroedinger equation (NLSE) reveals that the IAW may become unstable. The stability criteria depend on the IAW carrier wave number, and also on the ion temperature, the beam velocity and the beam electron density. Furthermore, the occurrence of localized envelope structures (solitons) is investigated, from first principles. The numerical analysis shows that the two first modes (essentially IAWs, modified due to the beam) present a complex behavior, essentially characterized by modulational stability for large wavelengths and instability for shorter ones. Dark-type envelope excitations (voids, holes) occur in the former case, while bright-type ones (pulses) appear in the latter. The latter two modes are characterized by an intrinsic instability, as the frequency develops a finite imaginary part for small ionic temperature values. At intermediate temperatures, both bright- and dark-type excitations may exist, although the numerical landscape is intertwined between stability and instability regions.},
doi = {10.1063/1.2182928},
journal = {Physics of Plasmas},
number = 4,
volume = 13,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}
  • A theoretical investigation has been made for ion-acoustic waves in an unmagnetized electron-positron-ion plasma. A more realistic situation in which plasma consists of a negatively charged ion fluid, free positrons, and trapped as well as free electrons is considered. The properties of stationary structures are studied by the reductive perturbation method, which is valid for small but finite amplitude limit, and by pseudopotential approach, which is valid for large amplitude. With an appropriate modified form of the electron number density, two new equations for the ion dynamics have been found. When deviations from isothermality are finite, the modified Korteweg-deVries equationmore » has been found, and for the case that deviations from isothermality are small, calculations lead to a generalized Korteweg-deVries equation. It is shown from both weakly and highly nonlinear analysis that the presence of the positrons may allow solitary waves to exist. It is found that the effect of the positron density changes the maximum value of the amplitude and M (Mach number) for which solitary waves can exist. The present theory is applicable to analyze arbitrary amplitude ion-acoustic waves associated with positrons which may occur in space plasma.« less
  • The propagation of ion-acoustic (IA) solitons is studied in a plasma system, comprised of warm ions and superthermal (Kappa distributed) electrons in the presence of an electron-beam by using a hydrodynamic model. In the linear analysis, it is seen that increasing the superthermality lowers the phase speed of the IA waves. On the other hand, in a fully nonlinear investigation, the Mach number range and characteristics of IA solitons are analyzed, parametrically and numerically. It is found that the accessible region for the existence of IA solitons reduces with increasing the superthermality. However, IA solitons with both negative and positivemore » polarities can coexist in the system. Additionally, solitary waves with both subsonic and supersonic speeds are predicted in the plasma, depending on the value of ion-temperature and the superthermality of electrons in the system. It is examined that there are upper critical values for beam parameters (i.e., density and velocity) after which, IA solitary waves could not propagate in the plasma. Furthermore, a typical interaction between IA waves and the electron-beam in the plasma is confirmed.« less
  • Effects of external magnetic field, ion temperature, and vortexlike electron distribution are incorporated in the study of nonlinear ion-acoustic waves in a hot magnetized plasma that consists of a positively charged, hot ion fluid and trapped, as well as, free electrons. It is found that, owing to the departure from the Boltzmann electron distribution to a vortexlike one, the dynamics of small but finite amplitude ion-acoustic waves is governed by a nonlinear equation of K-dV (Korteweg-de Vries) type. The latter admits a stationary ion-acoustic solitary wave solution, which has larger amplitude, smaller width, and higher propagation velocity, than that involvingmore » isothermal electrons. The effects of external magnetic field and ion temperature on the properties of these ion-acoustic solitary structures are also discussed. {copyright} {ital 1998 American Institute of Physics.}« less
  • The nonlinear propagation of dust-acoustic (DA) waves in an unmagnetized dusty plasma consisting of nonthermal electrons, vortex-like (trapped) distributed ions and mobile negative dust have been investigated by employing the reductive perturbation technique. The effects of nonthermal electrons and trapped ions are found to modify the properties of the DA solitary waves.