Electron exchange-correlation effects on dispersion properties of electrostatic waves in degenerate quantum plasmas

Based on the quantum Magnetohydrodynamic (QMHD) model, the obliquely propagation of electrostatic waves in degenerate magnetized quantum plasmas with electron exchange-correlation effects are theoretically investigated. The modified linear dispersion relations of electrostatic waves are obtained and discussed in some specific cases. The analytical results clearly show that the dispersion properties of the high frequency electron waves (including the Langmuir wave and upper-hybrid wave) and the low frequency ion acoustic wave are modified by the quantum effects together with the electron exchange-correlation effects. The numerical results depict that the Langmuir wave and upper-hybrid wave can be unstable in the presence of the electron exchange-correlation effects, and it is also evidently indicated that the electron exchange-correlation effects can reduce the phase velocity of the waves, especially in the high wave number region. The corresponding results should be of relevance for identifying electrostatic fluctuations which transport in an inhomogeneous and magnetized quantum plasmas.     

Dust-lower-hybrid waves in quantum plasmas

The dispersion relation of the dust-lower-hybrid wave has been derived using the quantum hydrodynamic model of plasmas in an ultracold Fermi dusty plasma in the presence of a uniform external magnetic field. The dust dynamics, electron Fermi temperature effect, and the quantum corrections give rise to significant effects on the dust-lower-hybrid wave of the magnetized quantum dusty plasmas.     

Dispersion of multi-stream instability in quantum magnetized hot plasmas

Using the quantum hydrodynamic (QHD) equations with magnetic field on the Wigner-Maxwell system, the general dielectric tensor and dispersion equation for quantum plasmas were derived. Dispersion relations of one-, two-stream and beam-plasma instabilities in uniform quantum magnetized plasmas are investigated through the new dielectric tensor. The magnetic field which is parallel to the fluid velocity does not work on stream instabilities. The quantum and thermal effects have remarkable impact on two-stream instability. The critical wave number for beam-plasma instability with quantum effects correction is given too.     

Two‐dimensional magnetosonic shock wave propagation in dense electron–positron–ion plasmas

Two‐dimensional (2D) magnetosonic wave propagation in magnetized quantum dissipative plasmas is studied. The plasma system is comprised of inertial ions, inertia‐less electrons, and positrons. The multi‐fluid quantum hydrodynamic model is used, in which quantum statistical and quantum tunnelling effects of electrons and positrons are included. Reductive perturbation analysis is performed to derive the Zabolotskaya–Khokhlov equation for the 2D propagation of a magnetosonic shock wave in a magnetized qauntum plasma. The effects of varying the different plasma parameters such as positron density and magnetic field intensity on the propagation characteristics of magnetosonic shock waves are discussed with non‐relativistic degenerate plasma parameters in astrophysical plasma situations.     

Drift wave turbulence in a dense semi-classical magnetoplasma

A semi-classical nonlinear collisional drift wave model for dense magnetized plasmas is developed and solved numerically. The effects of fluid electron density fluctuations associated with quantum statistical pressure and quantum Bohm force are included, and their influences on the collisional drift wave instability and the resulting fully developed nanoscale drift wave turbulence are discussed. It is found that the quantum effects increase the growth rate of the collisional drift wave instability, and introduce a finite de Broglie length screening on the drift wave turbulent density perturbations. The relevance to nanoscale turbulence in nonuniform dense magnetoplasmas is discussed.     

各向异性磁化等离子体JEC-FDTD算法

将色散介质的电流密度卷积-时域有限差分(JEC-FDTD)算法推广到各向异性磁化等离子体色散介质.该算法同时解决了电磁波在各向异性和频率色散介质中传播的难题，给出了各向异性磁化等离子体JEC-FDTD算法的公式.计算磁化等离子体平板对平行于磁场传播的电磁波的反射和透射系数，通过与解析结果的比较，验证了该算法的高效性和高精度. 关键词： 色散介质 FDTD算法 各向异性 磁化等离子体     

The instability of electrostatic wave in a magnetized dusty plasma with nonadiabatic dust charge fluctuation

The effects of external magnetized field and nonadiabatic dust charge fluctuation on instability of wave incorporating the nonthermally distributed ions and the temperatures of ion and dust in dusty plasmas are investigated. A linear dispersion relation is obtained. The numerical results show that the external magnetized field, fast ions and nonadiabatic dust charge fluctuation have strong influence on the frequency and the damping of wave.     

Nonlinear Behavior of Electromagnetic Waves in Ultra‐Relativistic Electron‐Positron Plasmas

A set of nonlinear equations which can self‐consistently describe the behavior of high frequency Electromagnetic (EM) waves in un‐magnetized, ultra‐relativistic electron‐positron (e‐p) plasmas is obtained on the basis of Vlasov‐Maxwell equations. Nonlinear wave‐wave, wave‐particle interactions lead to the coupling of high frequency EM waves with low frequency density perturbations which result from EM waves radiation pressure. The same as that in conventional electron‐ion (e‐i) plasmas, strong EM waves in e‐p plasmas will give rise to density depletion in which itself are trapped. But on the contrary to that in e‐i plasmas, there no longer exists electrostatic acoustic–like wave in e‐p plasmas due to the absence of mass difference. For linear polarized EM waves, a stationary EM soliton with a spiky structure will be formed. The possible relation of the localized field to pulsar radio pulse is discussed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

FDTD Analysis of Electromagnetic Reflection by Conductive Plane Covered with Magnetized Inhomogeneous Plasmas

A novel finite-difference time-domain (FDTD) methodology which incorporates both anisotropy and frequency dispersion at the same time is developed for electromagnetic wave propagation in anisotropic magnetoactive plasmas in this paper. The numerical verification of the method are confirmed by computing the reflection and transmission of right-handed/left-handed circularly polarized (RCP/LCP) wave through a magnetized plasma layer, with the direction of propagation parallel to the direction of the biasing field. And, the right-handed / left-handed polarized wave reflection coefficients for electromagnetic signals normally incident upon a conductive plane covered with a layer of magnetized plasma are computed using the new FDTD method. The parabolic electron-number density profile varies only in the direction perpendicular to the plane. The function dependence of reflection coefficients on the number density, collision frequency and external magnetic field is studied.     

Quantum effects on magnetization due to ponderomotive force in cold quantum plasmas

The quantum effects on the magnetization due to the ponderomotive force are investigated in cold quantum plasmas. It is shown that the ponderomotive force of the electromagnetic wave induces the magnetization and cyclotron motion in quantum plasmas. We also show that the magnetic field would not be induced without the quantum effects in plasmas. It is also found that the quantum effect enhances the cyclotron frequency due to the ponderomotive force related to the time variation of the field intensity. In addition, it is shown that the magnetization diminishes with an increase of the frequency of the electromagnetic field.     

Effects of dust size distribution in ultracold quantum dusty plasmas

The effect of dust size distribution in ultracold quantum dusty plasmas are investigated in this paper. How the dispersion relation and the propagation velocity for the quantum dusty plasma vary with the system parameters and the different dust distribution are studied. It is found that as the Fermi temperature of the dust grains increases the frequency of the wave increases for large wave number dust acoustic wave. The quantum parameter of H_d also increases the frequency of the large wave number dust acoustic wave. It is also found that the frequency ω₀ and the propagation velocity v₀ of quantum dust acoustic waves all increase as the total number density increases. They are greater for unusual dusty plasmas than those of the usual dusty plasma.     

Quantum-electrodynamical photon splitting in magnetized nonlinear pair plasmas

We present for the first time the nonlinear dynamics of quantum electrodynamic (QED) photon splitting in a strongly magnetized electron-positron (pair) plasma. By using a QED corrected Maxwell equation, we derive a set of equations that exhibit nonlinear couplings between electromagnetic (EM) waves due to nonlinear plasma currents and QED polarization and magnetization effects. Numerical analyses of our coupled nonlinear EM wave equations reveal the possibility of a more efficient decay channel, as well as new features of energy exchange among the three EM modes that are nonlinearly interacting in magnetized pair plasmas. Possible applications of our investigation to astrophysical settings, such as magnetars, are pointed out.     

Plasma-Maser Instability of Bernstein Mode in Presence of Magnetohydrodynamic Turbulence

A theoretical study is made on the amplification mechanism of electrostatic Bernstein mode wave in presence of kinetic Alfven wave turbulence in a magnetized plasma on the basis of plasma-maser interaction. It is shown that a test high frequency electrostativ Bernstein mode wave is unstable in the presence of low frequency kinetic Alfven wave turbulence. The growth rate of the Bernstein wave vanishes only in an unmagnetized plasma. Because of the universal existence of the kinetic Alfven waves in large scale plasmas, the results have potential importance in space and astrophysical radiation processes.     

Pair annihilation effects on dust ion acoustic surface wave in semi-bounded magnetized pair–ion–dust plasmas

The electron–positron pair annihilation effects on the dust ion acoustic surface wave are investigated in semi-bounded magnetized electron–positron–ion–dust plasmas. The dispersion relation of the low frequency dust ion acoustic surface wave is obtained by the plasma dielectric function with the specular reflection boundary condition. The results show that the frequency of the dust ion acoustic surface wave is found to be increased with increasing the annihilation of the electron–positron pair. In addition, the group velocity of the dust ion acoustic surface wave is also found to be increased with the annihilation of the electron–positron pair.     

Ion acoustic solitary waves with adiabatic ions in magnetized electron-positron-ion plasmas

Linear and nonlinear ion acoustic waves in the presence of adiabatically heated ions in magnetized electron-positron-ion plasmas are studied. The Sagdeev potential approach is employed to obtain the energy integral equation in such a mulitcomponent plasma using fluid theory. It is found that electron density humps are formed in the subsonic region in magnetized electron-positron-ion plasmas. The amplitude of electron density hump is decreased with the increase of hot ion temperature in electron-positron-ion plasmas. However, the increase in positron concentration and obliqueness of the wave increases the amplitude of nonlinear structure. The increase in positron concentration also reduces the width of the nonlinear structure in a magnetized multicomponent plasma. The numerical solutions in the form of solitary pulses are also presented for different plasma cases. The results may be applicable to astrophysical plasma situations, where magnetized electron-positron-ion plasma with hot ions can exist.     

Linear Analysis of Obliquely Propagating Longitudinal Waves in Partially Spin Polarized Degenerate Magnetized Plasma

Linear analysis of low frequency obliquely propagating electrostatic waves in a partially spin polarized degenerate magnetized plasma is presented. Using Fourier analysis, a general linear dispersion relation is derived for low frequency electrostatic lower hybrid(LH) wave, ion acoustic(IA) wave and ion cyclotron(IC) wave in the presence of electron spin polarization. It is found that the electron spin polarization gives birth to a new spin-dependent wave(spin electron acoustic wave) in the spectrum of these waves. Further, the electron spin polarization also causes drastic shifts in the frequency spectrum of these waves. These effects would have a strong bearing on wave phenomena in degenerate astrophysical plasmas.     

Plasma-maser interaction of langmuir wave with kinetic Alfvén wave turbulence

A theoretical study is made on the generation mechanism of Langmuir mode wave in the presence of kinetic Alfvén wave turbulence in a magnetized plasma on the basis of plasma-maser interaction. It is shown that a test high frequency Langmuir mode wave is unstable in the presence of low frequency kinetic Alfvén wave turbulence. The growth of the Langmuir wave occurs due to direct and polarization coupling terms. Because of the universal existence of the kinetic Alfvén waves in large scale plasmas, the results have potential importance in space and astrophysical radiation processes.     

Parametric instabilities in quantum plasmas with electron exchange-correlation effects

Parametric instabilities induced by the nonlinear interaction between high frequency quantum Langmuir waves and low frequency quantum ion-acoustic waves in quantum plasmas with the electron exchange-correlation effects are presented.By using the quantum hydrodynamic equations with the electron exchange-correlation correction,we obtain an effective quantum Zaharov model,which is then used to derive the modified dispersion relations and the growth rates of the decay and four-wave instabilities.The influences of the electron exchange-correlation effects and the quantum effects on the existence of quantum Langmuir waves and the parametric instabilities are discussed in detail.It is shown that the electron exchange-correlation effects and quantum effects are strongly coupled.The quantum Langmuir wave can propagate in quantum plasmas only when the electron exchange-correlation effects and the quantum effects satisfy a certain condition.The electron exchange-correlation effects tend to enhance the parametric instabilities,while quantum effects suppress the instabilities.     

Stationary rarefaction wave in magnetized Hall plasmas

We demonstrate the existence of a stationary rarefaction wave in a current-carrying plasma. The result unexpectedly mismatches with the commonly accepted viewpoint about the impossibility of rarefaction shocks in gases or plasmas. The discovered wave may appear when the magnetic field has penetrated into the plasma and magnetized the electrons. At this stage, the wave front is formed at the cathode and propagates towards the anode through the magnetized quasineutral plasma. The case of low collisionality is investigated analytically. This phenomenon could explain the recent surprising experimental observations of a local plasma density drop in several laboratory plasmas.