Semi-bounded Quantum Plasma Research Articles

Electrostatic Surface Modes Under Exchange–Correlation Effects in Semi-Bounded Quantum Plasma

Electrostatic Surface Modes Under Exchange–Correlation Effects in Semi-Bounded Quantum Plasma

Resonant streaming instability in a non-degenerate quantum plasma including the electron quantum recoil effect

The dispersion relation for the surface waves propagating at the interface of a semi-bounded quantum plasma containing non-degenerate electrons and streaming ions. The electron quantum recoil effect is included in the dielectric permittivity, and the growth rate of the surface waves which are resonant with the streaming ions is derived. It is found that the resonant growth rate decreases with an increase in the plasmon energy; hence, the increase in electron oscillation is found to suppress the instability of the surface wave. However, the resonant growth rate increases with an increase in the electron thermal energy because the energy surplus by electrons is responsible for the unstable mode. As the wave number increases, the rate of decline of the resonant growth rate decreases gradually.

Branching and resonant characteristics of surface plasma waves in a semi-bounded quantum plasma including spin-current effects

The dispersion relation for the waves propagating on the surface of a bounded quantum plasma with consideration of electron spin-current and ion-stream is derived and numerically investigated. We have found that one of the real parts of the wave frequency has the branching behavior beyond the instability domains. In such a region where the frequency branching occurs, the waves exhibit purely propagating mode. The resonant instability has also been investigated. We have found that when the phase velocity of the wave is close to the velocity of ion-stream the wave becomes unstable. However, the resonant growth rate is remarkably reduced by the effect of electron spin-current. The growth rate is also decreased by either the reduction of ion-stream velocity or the increase in quantum wavelength. Thus, the quantum effect in terms of the quantum wave number is found to suppress the resonant instability. It is also found that the increase in Fermi energy can reduce the growth rate of the resonant wave in the quantum plasma.

Broken degeneracy of low frequency surface waves in semi-bounded quantum plasmas including the quantum recoil effect

We present a derivation of the dispersion relation for electrostatic waves propagating at the interface of semi-bounded quantum plasma in which degenerate electrons are governed by the Wigner–Poisson system, while non-degenerate ions follow the classical fluid equations. We consider parameters for metallic plasmas in terms of the ratio of plasmon energy to Fermi energy. The dispersion relation is solved numerically and analyzed for various plasmon energies. The result shows that two-mode of waves can be possible: high- and low-mode. We have found that the degeneracy for high-mode wave would be broken when the plasmon energy is larger than the Fermi energy. We also discuss the characteristics of group velocities for high- and low-mode waves.

The effects of exchange–correlation on high-frequency electrostatic surface wave in magnetized quantum plasma through a porous medium

In this paper the propagation of an electrostatic surface wave at the interface between a vacuum and quantum plasma through a Brinkman porous medium is studied by considering exchange–correlation effects. A general analytical expression for dispersion relation is derived using the linearized quantum hydrodynamic model in conjunction with Poisson’s equation in the presence of a static and constant magnetic field. The growth and instability rates of electrostatic surface waves are obtained and separated. Numerical values are used to summarize and analyze the normalized dispersion relations for overcritical dense plasma condition in different cases. The results show that the behavior of surface plasmon waves can be significantly modified by the exchange–correlation effects which have different influences on the system stability. It is shown that the exchange–correlation effects caused the frequency of such waves to down-shift. It is found that the down-shift of the real part of frequency Re(Ω) by the exchange–correlation effect may increase by either increasing the plasmonic coupling H or increasing the porosity effects. In addition, it is shown that by increasing the magnetic field strength the group velocity is increased. Although the instability of the surface wave is decreased by increasing the plasmonic coupling H, it is increased by increasing the porosity effects (ν). The obtained results can help us in the physical understanding of the surface magnetized quantum wave on a semi-bounded quantum plasma through a porous media.

Bohm potential effect on the propagation of electrostatic surface wave in semi-bounded quantum plasmas

High frequency electrostatic wave propagation in a dense and semi-bounded electron quantum plasma is investigated with consideration of the Bohm potential. The dispersion relation for the surface mode of quantum plasma is derived and numerically analyzed. We found that the quantum effect enhances the frequency of the wave especially in the high wave number regime. However, the frequency of surface wave is found to be always lower than that of the bulk wave for the same quantum wave number. The group velocity of the surface wave for various quantum wave number is also obtained.

Excitation of surface modes by electron beam in semi-bounded quantum plasma

The excitation of the TM surface modes due to the interaction of electron beam with a semi-bounded quantum magnetized plasma is investigated. The generated current and the perturbed densities of the electron beam and plasma are obtained. The wave equation that describes the excited fields has been solved to obtain the dispersion relation for these modes. It is found that the quantum effects play important role for frequencies less and bigger than plasma frequency such that the phase velocity of modes increases with increasing the quantum effects compared to the classical case. It has also been displayed that in the absence of external magnetic field, the surface modes appear in the all regions of the wavelength while they have been only excited for high wavenumber in the presence of the magnetic field. Besides, it has been shown that the dispersion curves of the modes depend essentially on the density ratio of beam and plasma.

Propagation of TM-surface waves on semi-bounded quantum plasma through porous medium

The propagation of surface waves on a semi-bounded quantum plasma through a porous medium is investigated. The quantum hydrodynamic equations and Maxwell’s equations are linearized and used with the boundary conditions to derive the dispersion relation for the surface wave on a quantum electron plasma half-space. For the electrostatic limit [speed of light tends to infinity (c → ∞)], the dispersion relation is analytically studied. The results show that the quantum effects that is characterized by coupling (plasmonic) parameter, porosity and viscosity enhance the propagation velocity of these waves, while the medium permeability slows down the propagation velocity of these waves.

The exchange-correlation effects on surface plasmon oscillations in semi-bounded quantum plasma

We studied the surface plasmon waves in a quantum plasma half-space by considering the effects of exchange and correlation for the electrons. We used a quantum hydrodynamic approach, including the full set of Maxwell equations and considering two new quantities (measuring the exchange and correlation effects) in addition to the Fermi electron temperature and the quantum Bohm potential, to derive the dispersion relation for the surface plasmon waves. It was found that the exchange-correlation effects significantly modified the behavior of surface plasmon waves. We showed that the frequency of surface plasmon wave was down-shifted by the exchange-correlation effects. On the other hand, the quantum effects (including of the exchange-correlation effects and the quantum Bohm potential) was seen to cause an increase in the phase speed of surface plasmon waves. Our results can help to understand the propagation properties of surface waves in intense laser produced solid density plasmas and metallic plasmas.

Propagation of surface waves on a semi-bounded quantum magnetized collisional plasma

The propagation of surface waves on a semi-bounded quantum plasma in the presence of the external magnetic field and collisional effects is investigated by using quantum magnetohydrodynamics model. A general analytical expression for the dispersion relation of surface waves is obtained by considering the boundary conditions. It is shown that, in some special cases, the obtained dispersion relation reduces to the results reported in previous works. It is also indicated that the quantum, external magnetic field and collisional effects can facilitate the propagation of surface waves on a semi-bounded plasma. In addition, it is found that the growth rate of the surface wave instability is enhanced by increasing the collision frequency and plasmonic parameter.

Peculiarities of surface plasmons in quantum plasmas

AbstractSurface plasmons (SP) in a semi-bounded quantum plasma with degenerate electrons (e.g. a metal) are considered, and some interesting consequences of electron Pauli blocking for the SP dispersion and temporal attenuation are discussed. In particular, it is demonstrated that a semi-bounded degenerate plasma with a sharp boundary supportstwotypes of SP with distinct frequencies and qualitatively different temporal attenuation, in contrast to a non-degenerate hot plasma that only supports one type of SP.

Theoretical study of the surface waves in semi-bounded quantum collisional plasmas

The propagation of surface waves on a semi-bounded quantum plasma is investigated taking into account the collisional effects. The quantum hydrodynamic model includes Bohm’s quantum force, Fermi-Dirac statistical, and collisional corrections are used to derive the dispersion relation of these waves. It is shown that the collisions play a significant role on the decay of surface wave amplitude. Furthermore, the surface waves can be unstable in the presence of collisional effects. It is also indicated that the growth rate of the surface wave instability increases with the increase of collisional and quantum effects, especially in the high wavenumber region.

Propagation of TE-Surface Waves on Semi-Bounded Quantum Plasma

The propagation of the TE-surface waves on a semibounded quantum plasma is investigated by using the system of generalized quantum hydrodynamic (QHD) model and Maxwell's equations. The dispersion relations for these surface waves on quantum electron plasma in the presence of external magnetic field which is parallel to the wave propagation are derived. The perturbation of electron density and the electric fields of the TE-surface waves are also obtained. However, it was found that quantum effects (Bohm potential and statistical) have no remarkable action on the electric and magnetic field components in the case of unmagnetized plasma. But, it was found that the dispersion relation of surface modes depends significantly on these effects in the case of electrostatic or unmagnetized plasma.