Shabbir Ahmad Khan

• PhD Physics
• Professor (Associate) at Abdus Salam Centre for Physics

In a quantum plasma with strongly coupled ions and Fermi degenerate electron fluids, features of low frequency wave dispersion and nonlinear electrostatic structure formation are explored. Dynamics of strongly coupled ions is considered through a generalized momentum balance equation over the visco-elastic relaxation time for ion correlations and v...

Linearized modes of oscillation in terahertz range and weakly dissipating electrostatic solitary pulses are studied in semiconductor plasmas in the framework of quantum hydrodynamics. Many-particle effect is expressed in the local density approximation with the help of exchange-correlation potential and the species space charge effect is included t...

In this work, ion acoustic solitary pulses are investigated in an electron-ion quantum plasma in the presence of neutrals and many-particle effect of exchange-correlations in local density approximation. Quantum hydrodynamics formulation is used to derive nonlinear evolution equation in the form of a damped Korteweg-de Vries equation. Linear disper...

Quantum hydrodynamics analysis of electrostatic oscillations in single-walled carbon nanotubes (CNTs) is presented by considering a metallic CNT as a long cylindrical shell surrounded by degenerate electron-hole plasma, as well as non-degenerate ions and charged nanoparticles. Charging of nanoparticles takes place due to field emission with space c...

A kinetic description of electron plasma waves carrying orbital angular momentum is revisited by introducing a variable transformation, which confirms a more natural representation of wave propagation in electron–ion plasma extendable to an electron–positron plasma. Specifically, the twisted Landau resonance condition is expressed in a consistent w...

We have investigated the diamagnetic flow in a non‐uniform partially ionized plasma with non‐Maxwellian electron population to explain the dynamics of ion velocity shear‐induced low‐frequency drift mode and associated instabilities. The dispersion relations are found, and instability threshold conditions are pointed out along with ion‐parallel mome...

The localized electrostatic structures with dissipation due to ion-neutral collisions in a symmetric warm pair-ion plasma in the presence of non-Maxwellian population of electrons are studied. The analytical model for ion dynamics is based on fluid equations and the evolution equation is derived by using the reductive perturbation scheme in the for...

The electrostatic twisted modes with orbital angular momentum and associated kinetic instability are studied in a permeating space plasma containing streaming particle species. The plasma containing superthermal electrons and ions is modeled by using a non-gyrotropic Kappa distribution function which penetrates through a relatively slow moving (sta...

Twisted ion–acoustic excitations and the existence of kinetic instability are investigated in this study, accounting for finite orbital angular momentum states. For this purpose, a quasi‐neutral electron–ion plasma is considered, which permeates through another (target) plasma. The Vlasov‐Poisson model is used to obtain explicit expressions for wav...

New features of the twisted dusty plasma modes and associated instabilities are investigated in permeating plasmas. Using the Vlasov–Poisson model equations, a generalized dispersion relation is obtained for a Maxwellian distributed plasma to analyse the dust-acoustic and dust-ion-acoustic waves with finite orbital angular momentum (OAM) states. Ex...

Electrostatic ion oscillations carrying finite orbital angular momentum are investigated in an unmagnetized dense quantum degenerate plasma containing electrons, positrons, and ions. Instead of conventional plane wave solutions, Laguerre-Gaussian (LG) type density and potential profiles are considered to solve the wave equation in paraxial approxim...

We have investigated the properties of three-dimensional electrostatic ion solitary structures in highly dense collisional plasma composed of ultra-relativistically degenerate electrons and non-relativistic degenerate ions. In the limit of low ion-neutral collision rate, we have derived a damped Kadomtsev–Petviashvili (KP) equation using perturbati...

Owing to the fact that the helical wave structures with azimuthal phase dependence can exist and propagate longitudinally in a plasma, a kind of linearized ion-acoustic vortices or phonon modes are studied with orbital angular momentum in an unmagnetized uniform multi-component plasma. Laguerre-Gaussian (LG) type density and potential perturbations...

Electrostatic excitations in single-walled carbon nanotubes are investigated taking into account both the many-electron effects of exchange and correlations and the Fermi degeneracy pressure. Quantum hydrodynamics equations for electrons and ions are employed and solved by using the Fourier transformation technique to obtain the dispersion equation...

In the paraxial limit, a twisted electron-acoustic (EA) wave is studied in a collisionless unmagnetized plasma, whose constituents are the dynamical cold electrons and Boltzmannian hot electrons in the background of static positive ions. The analytical and numerical solutions of the plasma kinetic equation suggest that EA waves with finite amount o...

By employing the integral formulation of dielectric tensor, we have introduced the kinetic full wave analysis of ordinary-extraordinary-Bernstein (O-X-B) mode conversion in tokamak plasma in one dimension on the basis of TASK/W1 code using the finite element method. The boundary value problem of Maxwell's equation is solved and the finite Larmor ra...

Quantum ion-acoustic oscillations in single-walled carbon nanotubes are studied by employing a quantum hydrodynamics model. The dispersion equation is obtained by Fourier transformation, which exhibits the existence of quantum ion-acoustic wave affected by change of density balance due to presence of positive or negative heavy species as stationary...

We investigate the existence and propagation of low-frequency (in comparison to ion cyclotron frequency) electrostatic ion waves in highly dense inhomogeneous astrophysical magnetoplasma comprising relativistic degenerate electrons and non-degenerate ions. The dispersion equation is obtained by Fourier analysis under mean-field quantum hydrodynamic...

In this paper, we theoretically investigate the existence and propagation of low amplitude nonlinear ion waves in a dense plasma under the influence of a strong magnetic field. The plasma consists of ultra-relativistic and degenerate electrons and positrons and non-degenerate cold ions. Firstly, the appearance of two distinct linear modes and their...

A nonlinear Zakharov–Kuznetsov (ZK) equation for ion acoustic solitary waves (IASWs) is derived using the reductive perturbation method (RPM) for magnetized plasmas in which the inertialess electrons and positrons are nonextensively $q$-distributed while ions are assumed to be warm and inertial. It is found that both compressive as well as rarefact...

We investigate the features of weakly nonlinear waves in a collisional dense plasma consisting of ultrarelativistic degenerate electrons and non-relativistic degenerate ions. In weak dissipation limit, the dynamics of low frequency nonlinear ion (solitary) wave is described by solving a damped Korteweg-deVries equation. The analytical and numerical...

In this study, a potentiometric urea biosensor has been fabricated on glass filter paper through the immobilization of urease enzyme onto chitosan/cobalt oxide (CS/Co3O4) nanocomposite. A copper wire with diameter of 500 µm is attached with nanoparticles to extract the voltage output signal. The shape and dimensions of Co3O4 magnetic nanoparticles...

The kinetic theory of electron plasma waves with finite orbital angular momentum has recently been introduced by Mendonca. This model shows possibility of new kind of plasma waves and instabilities. We have extended the theory to ion-acoustic plasma vortices carrying orbital angular momentum. The dispersion equation is derived under paraxial approx...

Using macroscopic quantum hydrodynamic formulation, we study the dispersion properties of electrostatic electron plasma oscillations in single-walled carbon nanotubes. The electrons and ions are considered uniformly distributed over the cylindrical surface of a nanotube thus forming a two-component (electron-ion) quantum plasma system. Electron deg...

Quantum plasma physics is a rapidly evolving research field with a very inter-disciplinary scope of potential applications, ranging from nano-scale science in condensed matter to the vast scales of astrophysical objects. The theoretical description of quantum plasmas relies on various approaches, microscopic or macroscopic, some of which have obvio...

In this paper we study the coexisting low frequency oscillations in strongly degenerate, magnetized, (electron-positron) pair and warm pair-ion plasma. The dispersion relations are obtained for both the cases in macroscopic quantum hydrodynamics approximation. In pair-ion case, the dispersion equation shows coupling of electrostatic and (shear) ele...

In a three species electron-ion-dust plasma following a generalized non-Maxwellian distribution function (Lorentzian or kappa), it is shown that a kinetic instability of dust-acoustic mode exists. The instability threshold is affected when such (quasineutral) plasma permeates through another static plasma. Such case is of interest when the solar wi...

By employing quantum hydrodynamic formulation, oblique propagation of electrostatic ion waves and nonlinear structures are investigated in a magnetized dense Fermi plasma. Constituents are quantum (degenerate) electrons and non-degenerate mobile ions in presence of stationary massive ions (either positive or negative) in background. To reveal featu...

The existence of plasmons with orbital angular momentum due to the Laguerre–Gaussian-type density and potential perturbations is studied in an unmagnetized quantum plasma. Starting from appropriate hydrodynamic equations for the electrostatic electron dynamics, a dispersion equation is derived in paraxial approximation. The Laguerre–Gaussian beam s...

Theoretical investigation is carried out to understand the dynamics and stability of three dimensional ion solitary waves propagating in dense plasma comprising of ultra-relativistic degenerate electrons and positrons and warm ions. A linear dispersion relation is derived which shows a strong dependence of wave on positron concentration (through th...

It is shown that rarefactive-type double layer structures exist in ultradense electron—positron plasma. For this purpose, an extended Korteweg de Vries equation is derived and solved analytically in the low amplitude limit by employing the appropriate fluid equations. A strong influence of quantum degeneracy pressure of electrons and positrons, qua...

Quantum plasma oscillations are studied in a strongly magnetized, ultra-dense plasma with degenerate electrons and positrons. The dispersive role of electron and positron quantum effects on low frequency (in comparison to electron cyclotron frequency) shear electromagnetic wave is investigated by employing hydrodynamic formulation. In the presence...

It is shown that low frequency electrostatic ion mode couples with electromagnetic shear Alfven mode in a dense plasma containing strongly coupled non-degenerate ion and relativistic degenerate electron fluids. By employing the appropriate fluid equations, a linear dispersion equation is obtained which shows modifications due to ion correlations an...

The obtained experimental results due to nearest-neighbor spacing distributions were compared with simulated data using random matrix theory (RMT) with aid of the ultra relativistic quantum molecular dynamics (UrQMD) model. The present assessment reveals the primary level of multiplicity of secondary charged particles which might be linked with the...

Starting from appropriate fluid equations, a dispersion relation describing the properties of low frequency (as compared to the ion gyrofrequency) shear electromagnetic mode in an ultra-dense, relativistic-degenerate plasma is derived and examined. The plasma constituents are fully degenerate electrons and positrons, and strongly correlated non-deg...

The Kadomtsev–Petviashvili equation is derived for two-dimensional propagations of electrostatic solitons in unmagnetized dense pair-plasmas. The reductive perturbation method is employed and two-dimensional electrostatic potential hump structures are obtained. The conditions for a stable two-dimensional solitary structure are discussed using energ...

Low frequency electrostatic and electromagnetic waves are investigated in ultra-dense quantum magnetoplasma with relativistic-degenerate electron and non-degenerate ion fluids. The dispersion relation is derived for mobile as well as immobile ions by employing hydrodynamic equations for such plasma under the influence of electromagnetic forces and...

Low frequency electrostatic and electromagnetic waves in a dense magnetoplasma are studied. The dispersive contribution of electron quantum effects in an electron-ion plasma in the presence of positively or negatively charged dust particles in the background is emphasized. By employing the quantum hydrodynamic model, a linear dispersion relation is...

The formation and propagation of shocks and solitons are investigated in an unmagnetized, ultradense plasma containing degenerate Fermi gas of electrons and positrons, and classical ion gas by employing Thomas-Fermi model. For this purpose, a deformed Korteweg-de Vries-Berger (dKdVB) equation is derived using the reductive perturbative technique fo...

Plasmas are generally known as the hot gases of charged particles which behave classically under the action of electrostatic and electromagnetic forces. However, there are plasmas which don't fall in this category. These are low temperature/high density plasmas in which the plasma particles become so close that the interparticle distances become co...

The acoustic solitons and double layers are studied in unmagnetized quantum electron-positron plasmas in the presence of stationary ions. The quantum hydrodynamic model is employed and reductive perturbation method is used to derive the Korteweg–de Vries (KdV) and extended KdV equations for solitons and double layers, respectively. It is found that...

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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 wit...

The existence of small amplitude quantum ion-acoustic double layers is studied in an unmagnetized dense electron-positron-ion plasma. For this purpose, the quantum hydrodynamic model is employed to derive a deformed Korteweg–de Vries (dKdV) equation. The steady state double layer solution of dKdV equation is obtained and its dependence on various p...

The propagation of nonplanar quantum ion-acoustic solitary waves in a dense, unmagnetized electron-positronion (e-p-i) plasma are studied by using the Korteweg-de Vries (KdV) model. The quantum hydrodynamic (QHD) equations are used taking into account the quantum diffraction and quantum statistics corrections. The analytical and numerical solutions...

Two-dimensional, obliquely propagating nonlinear quantum dust-acoustic waves in dense magnetized plasmas are investigated on the basis of a quantum hydrodynamic model. In this regard, the Zakharov–Kuznetsov (ZK) equation is derived using the small amplitude approximation method. The extended hyperbolic tangent method is employed to obtain solitary...

Low frequency (in comparison to ion plasma frequency) ion-acoustic shocks and solitons in superdense electron–positron–ion quantum plasmas are studied. The quantum hydrodynamic model is used incorporating quantum Bohm forces and Fermi–Dirac statistical corrections to derive the deformed Korteweg de Vries–Burgers (dKdVB) equation in weakly nonlinear...

Using the quantum hydrodynamic model, quantum dust ion-acoustic solitary waves are investigated in the presence of weak transverse perturbations. The linear dispersion relation is obtained using the Fourier analysis. The two-dimensional (2D) propagation of small amplitude nonlinear waves is studied by deriving the Kadomtsev–Petviashvili (KP) equati...

A coupled linear dispersion relation for the basic electrostatic and electromagnetic waves in the ultracold nonuniform magnetized dense plasmas has been obtained which interestingly is analogous to the classical case. The scales of macroscopic phenomena and the interparticle quantum interactions are discussed. It is important to point out that hydr...

Obliquely propagating linear and weakly nonlinear ion-acoustic waves in a magnetized quantum plasma are investigated by employing the quantum hydrodynamic formulation. A linear dispersion relation is presented and the nonlinear Korteweg–de Vries equation is derived using the reductive perturbative method. The dispersion caused by the quantum diffra...

The linear and nonlinear quantum ion-acoustic waves propagating obliquely in two dimensions in superdense, magnetized electron-positron-ion quantum plasma are investigated on the basis of quantum hydrodynamic model. It is found in linear analysis that the quantum corrections of diffraction are important in the very short wavelength regime that may...

The low frequency electrostatic and electromagnetic linear modes in a nonuniform cold quantum electron-ion plasma are studied. The effect of stationary dust on an electrostatic mode is also investigated. The quantum corrections in the linear dispersion relations of a cold dense plasma are presented with possible applications. © 2008 American Instit...

The obliquely propagating two-dimensional quantum dust ion-acoustic solitary waves in a magnetized quantum dusty plasma are studied by using the quantum hydrodynamic model. A linear dispersion relation is obtained using the Fourier analysis, and a nonlinear quantum Zakharov-Kuznetsov equation is derived for small-amplitude perturbations. A stationa...

Dust ion-acoustic solitary waves in unmagnetized quantum plasmas are studied in spherical and cylindrical geometries. Using quantum hydrodynamic model, the electrostatic waves are investigated in the weakly nonlinear limit. A deformed Korteweg–de Vries (dKdV) equation is derived by using the reductive perturbation method and its numerical solutions...

By considering the one-dimensional quantum hydrodynamic model for a three-species ultracold quantum dusty plasma, the properties of dust-ion-acoustic waves are studied. The dispersion relation in the linear regime and the Korteweg–de Vries equation in the nonlinear regime are derived by incorporating quantum corrections. The quantum-mechanical effe...

The characteristics and stability of ion acoustic solitary wave with transverse perturbations are examined in ultracold quantum magnetospheric plasma consisting of electrons, positrons, and ions. Using the quantum hydrodynamic model, a dispersion relation in the linear regime, and the Kadomtsev-Petviashvili equation in the nonlinear regime are deri...