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 -