TY - JOUR

T1 - Electrostatic mode envelope excitations in e-p-i plasmas - Application in warm pair ion plasmas with a small fraction of stationary ions

AU - Esfandyari-Kalejahi, A.

AU - Kourakis, I.

AU - Mehdipoor, M.

AU - Shukla, P. K.

PY - 2006/11/3

Y1 - 2006/11/3

N2 - The nonlinear propagation of amplitude-modulated electrostatic wavepackets in an electron-positron-ion (e-p-i) plasma is considered, by employing a two-fluid plasma model. Considering propagation parallel to the external magnetic field, two distinct electrostatic modes are obtained, namely a quasi-thermal acoustic-like lower mode and a Langmuir-like optic-type upper one. These results equally apply in warm pair ion (e.g. fullerene) plasmas contaminated by a small fraction of stationary ions (or dust), in agreement with experimental observations and theoretical predictions in pair plasmas. Considering small yet weakly nonlinear deviations from equilibrium, and adopting a multiple-scales perturbation technique, the basic set of model equations is reduced to a nonlinear Schrödinger (NLS) equation for the slowly varying electric field perturbation amplitude. The analysis reveals that the lower (acoustic) mode is mostly stable for large wavelengths, and may propagate in the form of a dark-type envelope soliton (a void) modulating a carrier wavepacket, while the upper linear mode is intrinsically unstable, and thus favours the formation of bright-type envelope soliton (pulse) modulated wavepackets. The stability (instability) range for the acoustic (Langmuir-like optic) mode shifts to larger wavenumbers as the positive-to-negative ion temperature (density) ratio increases. These results may be of relevance in astrophysical contexts, where e-p-i plasmas are encountered, and may also serve as prediction of the behaviour of doped (or dust-contaminated) fullerene plasmas, in the laboratory.

AB - The nonlinear propagation of amplitude-modulated electrostatic wavepackets in an electron-positron-ion (e-p-i) plasma is considered, by employing a two-fluid plasma model. Considering propagation parallel to the external magnetic field, two distinct electrostatic modes are obtained, namely a quasi-thermal acoustic-like lower mode and a Langmuir-like optic-type upper one. These results equally apply in warm pair ion (e.g. fullerene) plasmas contaminated by a small fraction of stationary ions (or dust), in agreement with experimental observations and theoretical predictions in pair plasmas. Considering small yet weakly nonlinear deviations from equilibrium, and adopting a multiple-scales perturbation technique, the basic set of model equations is reduced to a nonlinear Schrödinger (NLS) equation for the slowly varying electric field perturbation amplitude. The analysis reveals that the lower (acoustic) mode is mostly stable for large wavelengths, and may propagate in the form of a dark-type envelope soliton (a void) modulating a carrier wavepacket, while the upper linear mode is intrinsically unstable, and thus favours the formation of bright-type envelope soliton (pulse) modulated wavepackets. The stability (instability) range for the acoustic (Langmuir-like optic) mode shifts to larger wavenumbers as the positive-to-negative ion temperature (density) ratio increases. These results may be of relevance in astrophysical contexts, where e-p-i plasmas are encountered, and may also serve as prediction of the behaviour of doped (or dust-contaminated) fullerene plasmas, in the laboratory.

UR - http://www.scopus.com/inward/record.url?scp=33846066511&partnerID=8YFLogxK

U2 - 10.1088/0305-4470/39/44/014

DO - 10.1088/0305-4470/39/44/014

M3 - Article

AN - SCOPUS:33846066511

SN - 0305-4470

VL - 39

SP - 13817

EP - 13830

JO - Journal of Physics A: Mathematical and General

JF - Journal of Physics A: Mathematical and General

IS - 44

M1 - 014

ER -