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

Journal Article · Sat Apr 15 00:00:00 EDT 2006 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2182928· OSTI ID:20782733

Esfandyari-Kalejahi, A; Kourakis, I; Dasmalchi, B; Sayarizadeh, M ^[1]

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1. Azarbaijan University of Tarbiat Moallem, Faculty of Science, Department of Physics, 51745-406, Tabriz (Iran, Islamic Republic of)

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.

• OSTI ID: 20782733
• Journal Information: Physics of Plasmas, Vol. 13, Issue 4; Other Information: DOI: 10.1063/1.2182928; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

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