Ch. Rozina

Jeans instability with exchange effects in quantum dusty magnetoplasmas

Jeans instability is examined in magnetized quantum dusty plasmas using the quantum hydrodynamic model. The quantum effects are considered via exchange-correlation potential, recoil effect, and Fermi degenerate pressure, in addition to thermal effects of plasma species. It is found that the electron exchange and correlation potential have significant effects over the threshold value of wave vector and Jeans instability. The presence of electron exchange and correlation effect shortens the time of dust sound that comparatively stabilizes the self gravitational collapse. The results at quantum scale are helpful in understanding the collapse of the self-gravitating dusty plasma systems.

Beam driven upper-hybrid-wave instability in quantized semiconductor plasmas

The excitation of Upper-Hybrid waves (UHWs) induced by electron beam in semiconductor plasma is examined using quantum hydrodynamic model. Various quantum effects are taken into account including recoil effect, Fermi degenerate pressure, and exchange-correlation potential. The bandwidth of the UHWs spectrum shows that the system supports purely growing unstable mode. The latter has been studied for diversified parameters of nano-sized GaAs semiconductor.

SNS potential with exchange field in quantum dusty plasmas

The shielding potential of a static test charge is studied in quantum dusty plasmas. The plasma system consisting upon electrons, ions and negatively static charged dust species, is embedded in an ambient magnetic field. The modified equation of dispersion is derived using quantum hydrodynamic model (QHD) for magnetized plasmas. The quantum effects are inculcated through Fermi degenerate pressure, tunneling effect and exchange-correlation effects. The study of shielding is important to know the existence of the silence zones in space and astrophysical objects as well as crystal formation. The graphical description of the normalized potential depict the significance of the exchange and correlation effects arising through spin and other variables on the shielding potential.

Jeans instability in a degenerate electron-positron-ion and classical dusty plasma

We follow the quantum hydrodynamic model to study the newly suggested problem of Jeans instability in collisionless self-gravitating multicomponent, dense, astrophysical quantum plasmas. Here, the quantum effects appear through the quantum diffraction and Fermi pressure, whereas the quantum statistical effects are important only for degenerate electron-positron- ion and dust being the heaviest is treated as classical. We have obtained dispersion relations for three particular plasmas; every time, Fermi pressure is found to be numerically larger than the quantum diffraction term which tends to stabilize Jeans instability even more than the Madelung term. The Jeans critical wave number and the corresponding critical mass are defined for particular plasmas. We have displayed our results numerically and have shown that the gravitational instability of quantum electron-ion-dust plasmas and electron-positron-dust plasmas is achieved by increasing both the number density and mass of the dust grains. Moreover, th...

Low frequency waves in streaming quantum dusty plasmas

The influence of quantum effects on the excitation of two instabilities, namely quantum dust-acoustic and quantum dust-lower-hybrid waves due to the free streaming of ion/dust particles in uniformly magnetized dusty plasmas has been investigated using a quantum hydrodynamic model. We have obtained dispersion relations under some particular conditions applied on streaming ions and two contrastreaming dust particle beams at equilibrium and have analyzed the growth rates graphically. We have shown that with the increase of both the electron number density and the streaming speed of ion there is enhancement in the instability due to the fact that the dense plasma particle system with more energetic species having a high speed results in the increase of the growth rate in the electrostatic mode. The application of this work has been pointed out for laboratory as well as for space dusty plasmas.

Modulation and filamentation instability of ultrarelativistic electromagnetic waves in electron-positron-ion plasma

In this study, we have analytically investigated the effects of nonlinear Landau damping on the temporal growth rate of modulation and filamentation instabilities. Here, the nonlocal nonlinear Landau damping phenomena is appearing due to the nonlinear interaction between ultrarelativistic electromagnetic (UREM) wave (having wave vector normal to the beam) and electron-positron-ion plasma. We found that the ultrarelativistic ponderomotive force is linear, while usually it is nonlinear in relativistic case. We construct three dimensional kinetic nonlinear Schrodinger equation for a slowly varying spatio and temporal amplitude of UREM waves. The equations are then Fourier analyzed to obtain dispersion relation, which admit both modulation and filamentation instabilities. It is shown that nonlinear Landau damping is the main source of modulation instability, for a particular condition taking into account later one the maximum growth rate of modulation instability obtained as a function of amplitude of UREM wa...

Parametric instabilities in a quantum magnetoplasma with electron exchange-correlations

Relying on the density functional theory, we have examined the impact of electron exchange-correlations on the nonlinear dispersion relations and associated parametric instabilities induced by nonlinear couplings of high-frequency quantum upper-hybrid waves (QUHWs) with different low-frequency waves, like quantum lower-hybrid waves (QLHWs), quantum ion-cyclotron waves (QICWs), and quantum Alfven waves (QAWs) in a dense quantum magnetoplasma. For theoretical description of waves, we make use of quantum hydrodynamic equations to account for the electron exchange-correlation and Bohm potentials, strongly dependent on the density fluctuations. At quantum scales, nonlinear dispersion equations are derived for QUHWs, QICWs, QLHWs, and QAWs and then Fourier transformed for obtaining the nonlinear dispersion relations and growth rates involving the three wave decay and modulational instabilities in dense quantum magnetoplasmas. The relevance to nonlinear interactions due to high- and low-frequency waves in perspe...

Potential surface waves at the vacuum-radiative collisional plasma interface

The stability of potential surface waves at the interface of collisional radiative electron-ion plasma and a vacuum is investigated. It is shown that the dynamics of electrons are affected by electromagnetic thermal radiation pressure significantly. The fluid model along with full set of Maxwells equations is used to develop dispersion relation of electrostatic surface waves on hot homogeneous radiative collisional plasma. It is found that electrostatic surface waves become unstable in the presence of electromagnetic thermal radiation and self collision of plasma particles; however, thermal radiations stabilize the surface waves in the absence of collisions. The analytical results are verified numerically for both the laboratory and ionosphere plasma environment. The study of surface waves may seek its applications at the nano as well as the astroscales.

Propagation of ultra-intense electromagnetic waves through electron-positron-ion plasma

A kinetic approach is used to study the propagation of ultrarelativistic (amplitude) electromagnetic waves through electron-positron-ion plasma. For our purposes, we formulate a new plasma particle distribution function in the presence of ultrarelativistically intense circularly polarized electromagnetic (EM) waves. An effective dispersion relation of constant amplitude ultrarelativistic EM wave is derived, skin depth is calculated in particular, frequency regimes and has shown numerically that the penetration depth increases with the amplitude of ultra-intense electromagnetic waves, λsk∼a12, i.e., plasma will be heated more in the region of skin depth. Next, we have found that the nonlinear interaction of ultrarelativistically intense EM waves of time and space varying amplitude leads to construct kinetic nonlinear Schrodinger equation (KNSE), containing both local and non-local nonlinear terms, where nonlocal nonlinear term appears due to density perturbations of plasma species. Taking the effects of th...

Kinetic Jeans instability and nonlinear damping of electromagnetic waves in self gravitating dusty plasma

A kinetic theory of the Jeans instability of a self gravitating dusty plasma has been developed in the presence of nonlinear Landau damping (NLD) term. We demonstrate that NLD alters the growth rate of the gravitational collapse of the gravitating dusty plasma. The dispersion relation of modified Jeans instability is obtained and analyzed for specific conditions. Jeans frequency is compared with the dust acoustic frequency; new definition of Jeans wave length is introduced. The maximum growth rate is obtained for a particular condition as well as the Jeans critical mass is defined. Next to address the heating of plasma through radiation processes, we investigate the nonlinear theory of high frequency electromagnetic waves (EMWs) in a collisionless dusty plasma by using a set of Vlasov-Poisson equations. The effects of the nonlocal nonlinear Landau term (appearing due to the nonlinear interaction of EMWs with gravitating dusty plasma) in the nonlinear Schrodinger equation are examined. It is found that non...