Browsing by Author "U. A., Mofiz"

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Growing electrostatic modes in the isothermal pair plasma of the pulsar magnetosphere
(© 2011 Springer Science+Business Media B.V., 2012) U. A., Mofiz; Amin, Md. Ruhul; Shukła, Padma Kant
It is shown that a strongly magnetized isothermal pair plasma near the surface of a pulsar supports low-frequency (in comparison to electron cyclotron frequency) toroidal electrostatic plasma modes in the equatorial region. Physically, the thermal pressure coupled with the magnetic pressure creates the low frequency oscillations which may grow for particular case of inhomogeneities of the equilibrium magnetic field and the pair plasma density.
Growing electrostatic modes in the isothermal pair plasma of the pulsar magnetosphere
(© 2011 Springer Science+Business Media B.V., 2012) U. A., Mofiz; Amin, Md. Ruhul; Shukła, Padma Kant
It is shown that a strongly magnetized isothermal pair plasma near the surface of a pulsar supports low-frequency (in comparison to electron cyclotron frequency) toroidal electrostatic plasma modes in the equatorial region. Physically, the thermal pressure coupled with the magnetic pressure creates the low frequency oscillations which may grow for particular case of inhomogeneities of the equilibrium magnetic field and the pair plasma density.
Langmuir dark solitons in dense ultrarelativistic electron-positron gravito-plasma in pulsar magnetosphere
(© 2013 Springer, 2013) U. A., Mofiz; Amin, M. R.
Nonlinear propagation of electrostatic modes in ultrarelativistic dense elelectron-positron gravito-plasma at the polar cap region of pulsar magnetosphere is considered. A nonlinear Schrödinger equation is obtained from the reductive perturbation method which predicts the existence of Langmuir dark solitons. Relevance of the propagating dark solitons to the pulsar radio emission is discussed.
Langmuir dark solitons in dense ultrarelativistic electron-positron gravito-plasma in pulsar magnetosphere
(© 2013 Springer, 2013) U. A., Mofiz; Amin, M. R.
Nonlinear propagation of electrostatic modes in ultrarelativistic dense elelectron-positron gravito-plasma at the polar cap region of pulsar magnetosphere is considered. A nonlinear Schrödinger equation is obtained from the reductive perturbation method which predicts the existence of Langmuir dark solitons. Relevance of the propagating dark solitons to the pulsar radio emission is discussed.
Optical solitons in negative-index meta-materials
(© 2013 IEEE, 2013) U. A., Mofiz
The nonlinear propagation of gigahertz electromagnetic wave propagation in the resonant region of a negative index meta-material is investigated. It is found that the negative refractive index is maintained within a narrow band of frequency which is more narrowed down with the intensity of the radiation. In the high frequency response, the nonlinear field dependent dispersion relation is obtained, and the corresponding group velocity is determined. In the low frequency response, coupled nonlinear Schrödinger equations are obtained which show the creation of bright and dark optical solitons. The bright soliton is a fast mode and it is modulationally unstable. The dark soliton is a slow mode and it is modulationally stable. Applications of these results to terahertz spectrums and in the photonic crystals are mentioned.
Optical solitons in negative-index meta-materials
(© 2013 IEEE, 2013) U. A., Mofiz
The nonlinear propagation of gigahertz electromagnetic wave propagation in the resonant region of a negative index meta-material is investigated. It is found that the negative refractive index is maintained within a narrow band of frequency which is more narrowed down with the intensity of the radiation. In the high frequency response, the nonlinear field dependent dispersion relation is obtained, and the corresponding group velocity is determined. In the low frequency response, coupled nonlinear Schrödinger equations are obtained which show the creation of bright and dark optical solitons. The bright soliton is a fast mode and it is modulationally unstable. The dark soliton is a slow mode and it is modulationally stable. Applications of these results to terahertz spectrums and in the photonic crystals are mentioned.