Quantum Magnetoplasma Research Articles

Modified screening potential in a high density inhomogeneous quantum dusty magnetoplasma

The effect of strong ambient static magnetic field on Shukla–Nambu–Salimullah (SNS) potential in a dusty quantum magnetoplasma has been investigated using quantum hydrodynamic model. The potential is significantly modified by quantum statistical effects, density inhomogeneity, and dust polarization drift effect. The effective length of the modified SNS potential is found to be a sensitive function of external static magnetic field, E×B0 drift, and the scale length of inhomogeneity. Here E is the electric polarization vector produced via density inhomogeneity, and B0 is the ambient static magnetic field. It is found that dust polarization drift effect predominates the ion polarization drift effect in high magnetic field environments. It attracts our attention to the careful study of the underlying physics of dusty plasma environment of neutron stars and magnetars.

Nonlinear electrostatic waves in inhomogeneous dense dusty magnetoplasmas

The nonlinear electrostatic drift waves are studied using quantum hydrodynamic model in dusty quantum magnetoplasmas. The dissipative effects due to collisions between ions and dust particles have also been taken into account. The Korteweg–de Vries Burgers (KdVB) like equation is derived and analytical solution is obtained using tanh method. The limiting cases of KdV type solitary waves, Burger type monotonic shock waves and oscillatory shock solutions are also presented. It is found that both hump and dip type solitary structures are possible in quantum dusty plasmas. However, amplitude and width of the nonlinear structure depend on the dust charge polarity and its concentration in electron–ion quantum plasmas. The monotonic shock like structure is independent of the quantum parameter. It is found that shock strength is increased in the presence of positively charged particles in comparison with negatively charged dust particles. The oscillatory shock structures are also obtained and it is found that change in dust charge polarity only shifts the phase of the oscillatory shock in plasmas. The numerical results are also presented for illustration.

Coupled nonlinear drift and ion acoustic waves in dense dissipative electron-positron-ion magnetoplasmas

Linear and nonlinear propagation characteristics of drift ion acoustic waves are investigated in an inhomogeneous electron-positron-ion (e-p-i) quantum magnetoplasma with neutrals in the background using the well known quantum hydrodynamic model. In this regard, Korteweg–de Vries–Burgers (KdVB) and Kadomtsev–Petviashvili–Burgers (KPB) equations are obtained. Furthermore, the solutions of KdVB and KPB equations are presented by using the tangent hyperbolic (tanh) method. The variation in the shock profile with the quantum Bohm potential, collision frequency, and the ratio of drift to shock velocity in the comoving frame, v*∕u, is also investigated. It is found that increasing the positron concentration and collision frequency decreases the strength of the shock. It is also shown that when the localized structure propagates with velocity greater than the diamagnetic drift velocity (i.e., u>v*), the shock strength decreases. However, the shock strength is observed to increase when the localized structure pro...

Counter-rotating coupled drift-acoustic vortices in the presence of sheared ion flows in electron-ion quantum magnetoplasmas

Nonlinear equations governing the dynamics of finite amplitude drift acoustic waves are derived by taking into account sheared ion flow perpendicular to the ambient magnetic field in a quantum magnetoplasma comprising of ions and electrons. It is shown that stationary solution of the nonlinear equations can be represented in the form of a counter-rotating vortex for a particular choice of the equilibrium profile. The counter-rotating vortices are, however, observed to form on very short scales, i.e., of the order of ion Larmor radius ρi in quantum plasmas. The relevance of the present investigation with regard to dense astrophysical environments is also pointed out.

Erratum: “Nonlinear electromagnetic wave equations for superdense magnetized plasmas” [Phys. Plasmas 16, 072114 (2009)

By using the quantum hydrodynamic and Maxwell equations, we derive nonlinear electron-magnetohydrodynamic (MHD), Hall-MHD, and dust Hall-MHD equations for dense quantum magnetoplasmas. The nonlinear equations include the electromagnetic, the electron pressure gradient, as well as the quantum electron tunneling and electron spin forces. They are useful for investigating a number of wave phenomena including linear and nonlinear electromagnetic waves, as well as three-dimensional electromagnetic wave turbulence spectra arising from the mode coupling processes in dense magnetoplasmas.

Jeans instability in quantum magnetoplasma with resistive effects

The Jeans instability in dense quantum plasmas is investigated in the presence of two dimensional magnetic fields and resistive effects. The resistive effects are shown to introduce instability whether the perturbation is stable or not in the ideal magnetohydrodynamic model. The analytical expressions of the growth rate of Jeans instability are obtained for both the finite and remarkable resistive effects cases. The results are relevant to dense astrophysical objects, e.g., neutron stars and the interior of white dwarfs, as well as low-temperature laboratory plasmas.

Retraction: “Jeans instability in quantum magnetoplasma with resistive effects” [Phys. Plasmas 16, 072101 (2009)

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Nonlinear electromagnetic wave equations for superdense magnetized plasmas

By using the quantum hydrodynamic and Maxwell equations, we derive the generalized nonlinear electron magnetohydrodynamic, the generalized nonlinear Hall-MHD (HMHD), and the generalized nonlinear dust HMHD equations in a self-gravitating dense magnetoplasma. Our nonlinear equations include the self-gravitating, the electromagnetic, the quantum statistical electron pressure, as well as the quantum electron tunneling and electron spin forces. They are useful for investigating a number of wave phenomena including linear and nonlinear electromagnetic waves, as well as three-dimensional electromagnetic wave turbulence spectra and structures arising from mode coupling processes at nanoscales in dense quantum magnetoplasmas.

Rayleigh–Taylor/gravitational instability in dense magnetoplasmas

The Rayleigh–Taylor instability is investigated in a nonuniform dense quantum magnetoplasma. For this purpose, a quantum hydrodynamical model is used for the electrons whereas the ions are assumed to be cold and classical. The dispersion relation for the Rayleigh–Taylor instability becomes modified with the quantum corrections associated with the Fermi pressure law and the quantum Bohm potential force. Numerically, it is found that the quantum speed and density gradient significantly modify the growth rate of RT instability. In a dense quantum magnetoplasma case, the linear growth rate of RT instability becomes significantly higher than its classical value and the modes are found to be highly localized. The present investigation should be useful in the studies of dense astrophysical magnetoplasmas as well as in laser-produced plasmas.

Surface waves in magnetized quantum electron-positron plasmas

AbstractThe dispersion properties of electrostatic surface waves propagating along the interface between a quantum magnetoplasma composed of electrons and positrons, and vacuum are studied by using a quantum magnetohydrodynamic plasma model. The general dispersion relation for arbitrary orientation of the magnetic field and the propagation vector is derived and analyzed in some special cases of interest (viz. when the magnetic field is directed parallel and perpendicular to the boundary surface). It is found that the quantum effects facilitate the propagation of electrostatic surface modes in a dense magnetoplasma. The effect of the external magnetic field is found to increase the frequency of the quantum surface wave. The existence of a singular wave on the boundary surface is also proved, and its properties are analyzed numerically. It is shown that the new wave characteristics appear due to the Rayleigh type of the wave.

Modified Debye screening potential in a magnetized quantum plasma

The effects of quantum mechanical influence and uniform static magnetic field on the Shukla–Nambu–Salimullah potential in an ultracold homogeneous electron–ion Fermi plasma have been examined in detail. It is noticed that the strong quantum effect arising through the Bohm potential and the ion polarization effect can give rise to a new oscillatory behavior of the screening potential beyond the shielding cloud which could explain a new type of possible robust ordered structure formation in the quantum magnetoplasma. However, the magnetic field enhances the Debye length perpendicular to the magnetic field in the weak quantum limit of the quantum plasma.

Linear coupling of Alfven waves and acoustic-type modes in dense quantum magnetoplasmas

A coupled dispersion relation of low frequency shear Alfven waves and electrostatic waves in a dense quantum magnetoplasma is derived by using hydrodynamic model. The dispersive contribution of electron quantum effects is discussed for dynamic as well as static ions. The dominant role of electron Fermi pressure is highlighted and its comparison with the quantum pressure arising due to quantum Bohm potential is presented. For illustrative purpose, the results are analyzed numerically. The relevance of present work with the dense astrophysical and laboratory plasmas is pointed out with possible consequences.

Obliquely propagating low frequency electromagnetic shock waves in two dimensional quantum magnetoplasmas

Linear and nonlinear propagation characteristics of low frequency magnetoacoustic waves in quantum magnetoplasmas are studied employing the quantum magnetohydrodynamic model. In this regard, a quantum Kadomtsev–Petviashvili–Burgers (KPB) equation is derived using the small amplitude expansion method. The dissipation is introduced by taking into account the kinematic viscosity among the plasma constituents. Furthermore, the solution of KPB equation is presented using the tangent hyperbolic (tanh) method. The variation in the fast and slow magnetoacoustic shock profiles with the quantum Bohm potential via increasing number density, obliqueness angle θ, magnetic field, and the resistivity are also investigated. It is observed that the aforementioned plasma parameters significantly modify the propagation characteristics of nonlinear magnetoacoustic shock waves in quantum magnetoplasmas. The relevance of the present investigation with regard to dense astrophysical environments is also pointed out.

Drift ion acoustic shock waves in an inhomogeneous two-dimensional quantum magnetoplasma

Linear and nonlinear propagation characteristics of drift ion acoustic waves are investigated in an inhomogeneous quantum plasma with neutrals in the background employing the quantum hydrodynamics (QHD) model. In this regard, a quantum Kadomtsev–Petviashvili–Burgers (KPB) equation is derived for the first time. It is shown that the ion acoustic wave couples with the drift wave if the parallel motion of ions is taken into account. Discrepancies in the earlier works on drift solitons and shocks in inhomogeneous plasmas are also pointed out and a correct theoretical framework is presented to study the one-dimensional as well as the two-dimensional propagation of shock waves in an inhomogeneous quantum plasma. Furthermore, the solution of KPB equation is presented using the tangent hyperbolic (tanh) method. The variation of the shock profile with the quantum Bohm potential, collision frequency, and ratio of drift to shock velocity in the comoving frame, v∗/u, are also investigated. It is found that increasing the number density and collision frequency enhances the strength of the shock. It is also shown that the fast drift shock (i.e., v∗/u>0) increases, whereas the slow drift shock (i.e., v∗/u<0) decreases the strength of the shock. The relevance of the present investigation with regard to dense astrophysical environments is also pointed out.

Potentials in a nonuniform quantum dusty magnetoplasma

Using the quantum hydrodynamic model for quantum magnetoplasmas, the Shukla–Nambu–Salimullah shielding potential and the far-field dynamical wake potential in a quantum dusty plasma with a nonuniform density and ambient static magnetic field have been investigated in detail. The short-range screening potential different from the symmetric Debye–Hückel potential and the long-range oscillatory wake potential are found to be significantly affected by the nonuniformities in the density and the static magnetic field. The far-field oscillatory wake-field potential can explain attraction among the same polarity charges leading to the possible ordered structures or coagulation in the inhomogeneous quantum dusty magnetoplasma.

Ion-acoustic vortices in a nonuniform, dissipative quantum magnetoplasma with sheared ion flows

By employing the quantum hydrodynamic model, linear and nonlinear properties of quantum ion-acoustic waves are studied in a nonuniform, dissipative quantum plasma with sheared ion flow parallel to the ambient magnetic field. It is shown that the shear flow parallel to the magnetic field can drive the quantum ion-acoustic wave unstable. Stationary solutions of the nonlinear equations that govern the quantum ion-acoustic waves are also obtained. It is found that electrostatic monopolar, dipolar, and vortex street type solutions can appear in such a plasma. It is observed that the inclusion of the quantum statistical and Bohm potential terms significantly modify the scalelengths of these structures. The present work may have relevance in the dense astrophysical environments where quantum effects are expected to play a significant role.

Dust acoustic vortices in an inhomogeneous quantum magnetoplasma with dissipation and sheared dust flows

Linear and nonlinear properties of quantum dust acoustic waves are studied in a nonuniform, dissipative quantum plasma with sheared dust flow parallel to the ambient magnetic field, using the quantum hydrodynamic model. It is shown that the shear dust flow parallel to the external magnetic field can drive the quantum dust-acoustic wave unstable provided it has a negative slope. Stationary solutions of the nonlinear equations that govern the quantum dust-acoustic waves are also obtained. It is found that electrostatic monopolar, dipolar, and vortex street-type solutions can appear in such a plasma. It is observed that the inclusion of dust, quantum statistical, and Bohm potential terms significantly modify the scale lengths of these nonlinear structures. The relevance of the present investigation with regard to the dense astrophysical environments is also pointed out.

A quantum hydrodynamic model for multicomponent quantum magnetoplasma with Jeans term

The effect of Jeans term in a multicomponent self-gravitating quantum magnetoplasma is investigated employing the quantum hydrodynamic (QHD) model. The effects of quantum Bohm potential and statistical terms as well as the ambient magnetic field are also investigated on both dust and ion dynamics driven waves in this Letter. We state the conditions that can drive the system unstable in the presence of Jeans term. The limiting cases are also presented. The present work may have relevance in the dense astrophysical environments where the self-gravitating effects are expected to play a pivotal role.

Spin magnetosonic shock-like waves in quantum plasmas

The propagation of one-dimensional shock-like waves (SLWs) in a dissipative quantum magnetoplasma medium is studied. A quantum magnetohydrodynamic (QMHD) model is used to take into account the effects of quantum force associated with the Bohm potential and the pressure-like spin force for electrons. It is shown that the nonlinear evolution equation [Korteweg–de-Vries–Burger (KdVB)], which describes the dynamics of small but finite amplitude magnetosonic waves (MSWs) (where the dissipation is provided by the plasma resistivity) exhibits both oscillatory and monotonic shock-like perturbations (SLPs) by the effects of collective tunneling and spin alignment. Both the quantum and spin force significantly modify the shock-like structures and the strength of SLPs. The theoretical results could be of important for strongly magnetized astrophysical (e.g., pulsars, magnetars) plasmas.

Nonlinear electrostatic drift waves in dense electron-positron-ion plasmas

The Korteweg–de Vries–Burgers (KdVB)-type equation is obtained using the quantum hydrodynamic model in an inhomogeneous electron-positron-ion quantum magnetoplasma with neutral particles in the background. The KdV-type solitary waves, Burgers-type monotonic, and oscillatory shock like solutions are discussed in different limits. The quantum parameter is also dependent on the positron concentration in dense multicomponent plasmas. It is found that both solitary hump and dip are formed and their amplitude and width are dependent on percentage presence of positrons in electron-ion plasmas. The height of the monotonic shock is decreased with the increase of positron concentration and it is independent of the quantum parameter in electron-positron-ion magnetized quantum plasmas. However, the amplitude of the oscillatory shock is dependent on positron concentration and quantum parameter in electron-positron-ion plasmas.