Showing papers by "Padma Kant Shukla published in 1997"
TL;DR: In this article, a set of nonlinear equations for multi-component partially ionized magnetoplasmas is developed, taking into account the contributions of frictional thermalization, collisional heating in the energy equations on one hand, and those of ionization and recombination in the continuity equations on the other hand.
Abstract: A set of nonlinear equations for multi-component partially ionized dusty magnetoplasmas is developed, taking into account the contributions of frictional thermalization, collisional heating in the energy equations on one hand, and those of ionization and recombination in the continuity equations on the other hand. The present nonlinear equations form a tool for numerical simulation studies of various collective effects in the presence of sources and sinks. However, in order to illustrate possible applications of the present system of equations, two examples of thermal condensation instabilities are discussed.
42 citations
TL;DR: In this paper, a general linear dispersion relation for the dust-acoustic and dust-ion acoustic waves in self-gravitating unmagnetized dusty plasmas is obtained, taking into account the dust charge perturbations.
Abstract: It is shown that the recently published work of Pandey and Dwivedi [J. Plasma Phys. 55, 395 (1996)] dealing with dust-acoustic waves in a self-gravitating unmagnetized dusty plasma is erroneous. This is demonstrated on the basis of a dispersion relation in which gravitational and electrostatic forces are kept on an equal footing. Furthermore, a general linear dispersion relation for the dust-acoustic and dust-ion acoustic waves in self-gravitating dusty plasmas is obtained, taking into account the dust-charge perturbations. Specific results for limiting cases are discussed.
34 citations
TL;DR: In this paper, the nonlinear propagation of coupled Langmuir and ion-acoustic waves in a two-electron temperature plasma is shown to be governed by a generalized Schrodinger-Boussinesq system, which for uni-directional propagation reduces to the coupled Korteweg-de Vries (K-dV) system.
Abstract: The nonlinear propagation of coupled Langmuir and ion-acoustic waves in a two-electron temperature plasma is shown to be governed by a generalized Schrodinger–Boussinesq system, which for uni-directional propagation reduces to the coupled Schrodinger–Korteweg-de Vries (K-dV) system. For stationary propagation of the coupled waves, the Schrodinger–Boussinesq (or K-dV) system leads to a generic Hamiltonian which is shown to be integrable in the sub- as well as supersonic regimes of the Mach number. Different classes of exact analytical solutions of the stationary Schrodinger–Boussinesq system are explicitly obtained. Two-electron temperature plasmas are shown to admit a new class of coupled Langmuir–ion-acoustic solitons which propagate with supersonic speeds but are accompanied by density rarefactions. We also derive exact governing equations valid for large amplitude waves, and obtain their approximate solutions. Existence conditions for large amplitude localized solutions in the quasi-neutral limit are d...
32 citations
TL;DR: In this article, a linear dispersion relation for electrostatic dust-acoustic waves has been derived, taking into account the dynamics of neutral atoms in weakly ionized dusty plasmas.
Abstract: A linear dispersion relation for electrostatic dust-acoustic waves has been derived, taking into account the dynamics of neutral atoms in weakly ionized dusty plasmas. Explicit expressions for the temporal and spatial attenuation rates of dust-acoustic waves due to collisions of ions and dust grains with neutral atoms are presented.
31 citations
TL;DR: In this article, the nonlinear evolution of electrostatic dust-acoustic waves in a uniform gravitating dusty plasma is discussed, where self-gravitation does not affect the linear behavior of the modes, but comes into play at the non-linear level.
Abstract: We discuss the nonlinear evolution of electrostatic dust-acoustic waves in a uniform gravitating dusty plasma, when self-gravitation does not affect the linear behavior of the modes, but comes into play at the nonlinear level. This is valid for grains which are not too massive, as their charge-to-mass ratios are too high to make Coulomb and gravitational forces fully comparable. In our multispecies dusty plasma all species are treated alike, including pressure and gravitational effects. Afterwards we specialize our results to cold dust, in the presence of Boltzmann electrons and ions. The nonlinear behaviour is governed by an extended Korteweg-de Vries equation with a source term, similar in structure to the one describing perpendicular magnetosonic waves in a bi-ion plasma. It is a nonintegrable equation, so that no classic solitons or double layers are possible, although the equation could be tackled by perturbative iteration or by means of numerical analysis.
23 citations
TL;DR: In this article, a Korteweg-de Vries (KDV) equation was derived for small, but finite, amplitude dust-acoustic waves in a dusty plasma consisting of electrons, ions and charged dust particles.
19 citations
TL;DR: In this article, the ponderomotive force of a nonuniform intense neutrino beam can generate large scale quasi-stationary magnetic fields in a dense electron plasma, which can be responsible for the origin of magnetic field in the early universe.
16 citations
TL;DR: In this article, it was shown that intense neutrino fluxes can nonlinearly generate elliptically polarized electromagnetic waves in ionized super-dense gases immersed in an external magnetic field.
10 citations
TL;DR: In this article, the nonlinear propagation of an intense neutrino flux in an electron-positron plasma with equilibrium density and magnetic field inhomogeneities is considered, and it is found that the neutrinos are nonlinearly coupled with electrostatic and electromagnetic disturbances due to weak Fermi interaction and ponderomotive forces.
10 citations
TL;DR: In this article, it was shown that the nonlinear equations governing the dynamics of weakly interacting electromagnetic disturbances in nonuniform magnetoplasmas can be written as a set of three coupled non-linear equations, which are a generalization of the Lorentz-Stenfloors equations.
TL;DR: In this paper, the growth rate of the ETG-driven dust-acoustic modes is obtained, and it is found that nonthermal dustacoustic fluctuations can cause cross-field anomalous electron diffusion and electron thermal transport in dusty plasmas.
TL;DR: In this paper, the potential of a test particle in the presence of electron-acoustic waves in a uniform unmagnetized plasma has been obtained, and an oscillatory wake potential behind the test particle is found.
Abstract: The potential of a test particle in the presence of electron-acoustic waves in a uniform unmagnetized plasma has been obtained. Besides the well known Debye-Huckel potential, an oscillatory wake potential behind a test particle is found. The relevance of our investigation to macroparticles in plasmas with two distinct groups of electrons has been discussed.
TL;DR: In this article, the nonlinear excitation of low-frequency electrostatic waves by a high-power pump wave is re-examined and simple formulas that are relevant for ionospheric heating experiments are presented.
TL;DR: In this paper, a new version of the Brownian motion describing the motion of a dust particle in a turbulent plasma is considered, where the stochastic force acting on the dust particle is due to fluctuations of the plasma potential and not due to the usual molecular collisions.
Abstract: A new version of the Brownian motion describing the motion of a dust particle in a turbulent plasma is considered. Here, the stochastic force acting on the dust particle is due to the fluctuations of the plasma potential and not due to the usual molecular collisions. Another significant difference is due to the fact that the dust electric charge is not constant but fluctuates with the potential. A four-dimensional formulation of the problem is also given.A new version of the Brownian motion describing the motion of a dust particle in a turbulent plasma is considered. Here, the stochastic force acting on the dust particle is due to the fluctuations of the plasma potential and not due to the usual molecular collisions. Another significant difference is due to the fact that the dust electric charge is not constant but fluctuates with the potential. A four-dimensional formulation of the problem is also given.
TL;DR: In this article, the reflection and transmission of an electromagnetic wave pulse incident on a strongly nonlinear medium are considered, and an exact analytical solution is found for a rather general medium model that is characterized by two arbitrary parameters.
Abstract: The reflection and transmission of an electromagnetic wave pulse incident on a strongly nonlinear medium are considered. An exact analytical solution is found for a rather general medium model that is characterized by two arbitrary parameters. It is shown that almost all the incident energy of some pulse forms can be reflected at large amplitudes, whereas small amplitude fields are transmitted through the medium. For other pulse forms, part of the reflected pulse can reverse its polarization due to the time dependence of the reflection coefficient.
Book•
01 Sep 1997
TL;DR: In this paper, the authors discuss the interaction between dust crystals and dust plasmas in the atmosphere and space and other topics related to dust dynamics and interactions in the environment and space.
Abstract: Waves and interactions in dusty plasmas dust crystals dust dynamics dusty plasmas in the atmosphere and space other topics.
TL;DR: In this article, a description of nonstationary simple waves and Riemann invariants in a relativistically hot electron-positron magnetoplasma is presented, where the photon energy far exceeds the internal kinetic energy and the particle effective mass depends strongly on temperature.
Abstract: A description of nonstationary simple waves and Riemann invariants in a relativistically hot electron-positron magnetoplasma is presented. It is noted that at relativistic temperatures the photon energy far exceeds the internal kinetic energy and that the particle effective mass depends strongly on the temperature. Starting from a set of relativistic radiation magnetohydrodynamic equations, the nonlinear characteristics and velocities of simple waves are obtained. The equations are further employed to examine the Riemann invariants in the presence of isentropic flow. It is found that at ultra-relativistic temperatures the photon pressure and the relativistic mass variation play a very important role.
TL;DR: In this paper, a new dispersion relation for low-frequency magnetic electron drift modes (MEDV) in a nonuniform plasma is derived by incorporating the ion dynamics, which introduces new classes of instabilities when the wave frequency either lies between the electron and ion plasmas frequencies or is close to the ion plasma frequency.
Abstract: A new dispersion relation for low-frequency magnetic electron drift modes (MEDV) in a nonuniform plasma is derived by incorporating the ion dynamics. It is shown that the ion dynamics introduces new classes of instabilities when the wave frequency either lies between the electron and ion plasmas frequencies or is close to the ion plasma frequency. The modified MEDV modes involving the ion motion can cause nonthermal particle as well as electron heat transports.
TL;DR: In this paper, a nonlinear coupling between intense neutrino fluxes and electrostatic electron-cyclotronharmonic and convection modes in a nonuniform magnetoplasma is presented.
01 Dec 1997
TL;DR: In this article, the authors discuss the interaction between dust crystals and dust plasmas in the atmosphere and space and other topics related to dust dynamics and interactions in the environment and space.
Abstract: Waves and interactions in dusty plasmas dust crystals dust dynamics dusty plasmas in the atmosphere and space other topics.
TL;DR: In this paper, the nonlinear coupling between intense neutrino fluxes and a dense magnetized plasma is considered, and it is shown that the coupling is governed by a pair of equations consisting of a nonlinear Klein-Gordon equation for the neutrinos and an equation governing a variety of magnetized plasmas that are driven by the Neutrino energy density, which are then used to investigate parametric instabilities, envelope solitons, as well as wake field generation.
Abstract: The nonlinear coupling between intense neutrino fluxes and a dense magnetized plasma is considered. It is shown that the coupling is governed by a pair of equations consisting of a nonlinear Klein-Gordon equation for the neutrinos and an equation governing a variety of magnetized plasma waves that are driven by the neutrino energy density. The system of equations is then used to investigate parametric instabilities, envelope solitons, as well as wake field generation. The relevance of our investigation to supernova explosions in pointed out.
Journal Article•
TL;DR: In this article, the instability of random-phase kinetic Alfven waves against quasi-stationary perturbations is examined and an explicit expression for the increment of the modulational interaction is presented.
TL;DR: In this paper, a nonlinear coupling of intense radio waves with the low-frequency electrostatic perturbations of multi-component collisional plasmas is considered, assuming the presence of two distinct groups of electrons and singly charged ions, and equations for the radio wave sidebands and plasma slow motions that are driven by the combined effects of the radiation pressure and the differential Joule heating of the electrons.
TL;DR: In this article, the rippling instability of magnetic shock waves in a relativistically hot plasma with photon gas has been investigated and conditions under which spontaneous amplification of surface ripples on the discontinuity occurs, are obtained.
Abstract: The rippling instability of magnetic shock waves in a relativistically hot plasma with photon gas has been investigated. Conditions under which spontaneous amplification of surface ripples on the discontinuity occurs, are obtained. The rippling instability may cause the condensation of the plasma number density as well as the magnetic field behind the shock wave.