Nonlinear Plasma Waves Research Articles

Periodic low-frequency electric field structures in a magnetized non-thermal auroral plasma

The theoretical explanation of electric field structures associated with density depletion in the Earth's upper ionosphere is presented. Using the quasi-neutrality hypothesis, the effect of excess energetic electron species is studied on the evolution of nonlinear low-frequency ion-cyclotron and ion-acoustic waves in a magnetized auroral plasma. The dynamics of the cold ion beam is governed by the fluid equations and the electron is treated as energetic species with non-thermal density distribution. Numerical computations appear in a series of periodic oscillations, such as spiky, sawtooth and sinusoidal waveforms. The present model can generate up to 18 mV/m electric field amplitude, which is in the range of the FREJA satellite measurements in the auroral acceleration region.

Propagation of Solitary Waves and Double-Layers in Electron–Positron Pair Plasmas with Stationary Ions and Nonextensive Electrons

Based on reductive perturbation theory, the nonlinear structure of non-extensive multispecies plasma containing hot electrons, adiabatic cold electrons, cold positrons and ions has been investigated via different nonlinear KdV, mKdV and Gardner’s equations. It is shown that the formation and properties of electron acoustic solitary waves and double-layer can exist in such plasma system depending on some relevant physical parameters such as electron and positron density ratios, electrons temperatures ratio and non-extensive parameter. The existence conditions of these types of waves are extensively discussed. The obtained results may be useful in improving and understanding the propagation of the nonlinear electron waves in space plasma, Earth’s magnetosphere and solar wind.

KdV acoustic structure with exchange-correlation potential in plasmas

The effect of the exchange-correlation potential (ECP) on the profile of dust-acoustic solitary waves (DASWs) in dusty plasma containing degenerate electrons and ions was investigated. The present study focuses on the linear and nonlinear long-wavelength dust-acoustic waves in non-relativistic plasmas. The linear acoustic waves are analyzed using the multi-fluid model, whereas the reductive perturbation theory is applied to derive a modified Korteweg-de Vries (KdV) equation for small- but finite-amplitude waves. The effects of dust concentration and the exchange-correlation potential were investigated. These parameters remarkably change the amplitude and the width of the solitary waves. The findings from this investigation may lead to further understanding of the characteristics of nonlinear electrostatic waves exciting in the dense Fermi gas which is present in metallic nano structures or in near-supernovae environment in the presence of massive charge defects.

Effect of variable dust size, charge and mass on dust acoustic solitary waves in nonextensive magnetized plasma

Effects of variable dust size, mass and charge on the characteristics of nonlinear dust acoustic solitary waves (DASW) in a two-temperature ion dusty plasma have been studied analytically. Plasma ions are assumed to be Maxwellian while plasma electrons are nonextensively distributed. Mass and electrical charge of dust particles are assumed to be proportional to their size. Plasma is embedded in an external magnetic field with variable direction. The Zakharov–Kuznetsov equation was derived using reductive perturbation method, and its solitary answers were extracted. Dispersion relation of DASW shows that this wave may generate in plasma only if the nonextensivity coefficient, q, is positive. For all allowed magnitudes of c (the ratio of the largest dust radius to smallest dust radius) and q, only rarefactive solitons may be formed in plasma. Effect of variable dust size on the width and amplitude of DASW is noticeable when c is smaller than 3. Both the width and amplitude of DASW increase with increasing c, and with increasing the nonextensivity of plasma, effect of variable size increases. Results show that increasing the strength of external magnetic field leads to localization of DASW while both the width and amplitude of DASW are under the influence of the direction of the external magnetic field simultaneously.

Interaction behavior associated with a generalized (2+1)-dimensional Hirota bilinear equation for nonlinear waves

• A generalized bilinear equation is proposed and linked with a nonlinear model describing nonlinear wave in fluids and oceans. • Two types of interaction solution (lump-kink and lump-soliton) have been derived, based on which rogue wave may be predicted. • Completely non-elastic interaction between lump and stripe has been presented (the lump is drowned/shallowed by the stripe). • Interaction between lump and soliton has been given (lump moves from one branch to the other branch of the soliton). • These phenomena exhibit the dynamical process of nonlinear waves and are useful to study the nonlinear interaction behavior. In this paper, we focus on the interaction behavior associated with a generalized (2+1)-dimensional Hirota bilinear equation. With symbolic computation, two types of interaction solutions including lump-kink and lump-soliton ones are derived through mixing two positive quadratic functions with an exponential function, or two positive quadratic functions with a hyperbolic cosine function in the bilinear equation. The completely non-elastic interaction between a lump and a stripe is presented, which shows the lump is drowned or shallowed by the stripe. The interaction between lump and soliton is also given, where the lump moves from one branch to the other branch of the soliton. These phenomena exhibit the dynamics of nonlinear waves and the solutions are useful for the study on interaction behavior of nonlinear waves in shallow water, plasma, nonlinear optics and Bose–Einstein condensates.

Obliquely propagating nonlinear ion-acoustic solitary and cnoidal waves in nonrelativistic magnetized pair-ion plasma with superthermal electrons

The nonlinear propagation of ion-acoustic waves is considered in a magnetized system of collisionless and dissipative pair-ion plasma, composed of cold positively and negatively charged nonrelativistic ions, with superthermal electrons. obliquely propagating ion-acoustic solitary and cnoidal waves are investigated via a mechanical-motion analog Korteweg de Vries (KdV) approach. The characteristics of the emerged nonlinear magnetized waves are significantly modified by the effects of plasma parameters like the obliquity angle, superthermality parameter, negative to positive ions density ratio, electron density and it is also affected by the electron temperature. The obtained results can be generalized to be used to investigate the plasma waves nature in neutron stars, Saturn’s and Pulsars magnetospheres in addition to the laboratory plasmas.

Nonlinear ion flux caused by dust ion-acoustic nonlinear periodic waves in non-thermal plasmas

The propagation of dust ion-acoustic nonlinear periodic (cnoidal) waves is investigated in an unmagnetised dusty plasma characterised by a non-thermal electron population. The equations describing the dynamics of the wave potential in the first and second orders of perturbation theory are derived, and their non-secular periodic solutions are found. The average nonlinear ion flux caused by the propagation of a cnoidal wave is determined. The nonlinear ion flux is found to depend significantly on dust concentration and non-thermality parameter.

Dynamics of relativistic laser-produced plasmas

We present a brief overview of physical processes in a plasma under the action of relativistically strong electromagnetic radiation generated by high-power lasers. Attention is focused on nonlinear waves in a laser plasma for the creation of compact electron accelerators. Then, we address the acceleration of plasma bunches by the radiation pressure of light, which is the most efficient regime of ion acceleration. Coherent hard electromagnetic radiation in the relativistic plasma is generated in the form of high harmonics and/or electromagnetic pulses, which are compressed and intensified after reflection from relativistic mirrors created by nonlinear plasma waves. These processes are of interest in view of the development of novel methods for acceleration of charged particles and the development of sources of bright and hard electromagnetic radiation.

Nonlinear dust magnetosonic waves in collisional plasma

The excitations and damping of nonlinear dust magnetosonic waves in dissipative plasma are investigated. The dynamics of negatively charged dust particles is considered. The dissipation is taken due to dust neutral collisions. The ions and electrons are inertialess on dust dynamic scale. The temperature of ions and electrons is also taken into account. The linear dispersion charteristics of dust magnetosonic waves are discussed for different values of plasma parameters. For this purpose we have derived Damped Korteweg de Vries (DKdV) equation by applying the reductive perturbation method. For weak dissipation the analytical solution of DKdV is presented. For the numerical solution, we apply a two-level finite difference scheme with the help of the Runge-Kutta method. The effects of variations of different plasma parameters on the damping of nonlinear dust magnetosonic solitary wave structures are discussed.

Controlled electron injection facilitated by nanoparticles for laser wakefield acceleration

We propose a novel injection scheme for laser-driven wakefield acceleration in which controllable localized electron injection is obtained by inserting nanoparticles into a plasma medium. The nanoparticles provide a very confined electric field that triggers localized electron injection where nonlinear plasma waves are excited but not sufficient for background electrons self-injection. We present a theoretical model to describe the conditions and properties of the electron injection in the presence of nanoparticles. Multi-dimensional particle-in-cell (PIC) simulations demonstrate that the total charge of the injected electron beam can be controlled by the position, number, size, and density of the nanoparticles. The PIC simulation also indicates that a 5-GeV electron beam with an energy spread below 1% can be obtained with a 0.5-PW laser pulse by using the nanoparticle-assisted laser wakefield acceleration.

Lie symmetry analysis and some exact solutions for modified Zakharov–Kuznetsov equation

In this study, the Lie symmetry method is used to perform detailed analysis on the modified Zakharov–Kuznetsov equation. We have obtained the infinitesimal generators, commutator table of Lie algebra and symmetry group. In addition to that, optimal system of one-dimensional subalgebras up to conjugacy is derived and used to construct distinct exact solutions. These solutions describe the dynamics of nonlinear waves in isothermal multicomponent magnetized plasmas.

Nonlinear ion acoustic waves in a relativistic degenerate plasma with Landau diamagnetism and electron trapping

We consider the effects of trapping in a relativistic degenerate plasma with quantizing magnetic field. The linear dispersion relation for such an ion acoustic wave is derived and the propagation characteristics of these waves are discussed. The Sagdeev potential for the formation of arbitrary amplitude solitary structures is obtained and it is seen that only compressive solitary structures are formed for the relativistic degenerate quantized magnetoplasma. The dependence of the linear and nonlinear propagation characteristics of ion acoustic waves on different plasma parameters is explored. A comparison is also made with the previous studies. The useful applications of the present investigation in dense astrophysical environments like white dwarf stars and neutron stars, in semiconductor physics, in high-energy density physics, in inertial confinement fusion and in next generation laser–plasma interaction experiments are pointed out.

Characterization of wavebreaking time and dissipation of weakly nonlinear wakefields due to ion motion

In an initially uniform plasma, the lifetime of a weakly nonlinear plasma wave excited by a short driver is limited by the ion dynamics. The wakefield contains a slowly varying radial component, which results in a perturbation of the ion density profile and consequent destruction of the plasma wave. We suggest a novel method of characterizing the wave lifetime in numerical simulations quantitatively and study how the lifetime scales with the ion mass. We also discuss the implications of the limited lifetime on a recently proposed method of generating high-power terahertz radiation with counterpropagating wakefields driven by colliding laser pulses.

Nonlinear kinetic Alfven waves in space plasmas with generalized ( r , q $r,q$ ) distribution

In this paper, we have investigated linear and nonlinear propagation of kinetic Alfven waves in which the electrons have been assumed to follow generalized ( $r,q$ ) distribution. We have shown that ( $r,q$ ) distribution gives us most of the distributions observed in space plasmas. We have varied the flatness parameter $r$ and the tail parameter $q$ to explore the linear and nonlinear propagation characteristics of kinetic Alfven waves. We have also discussed the limiting cases. It has been shown that our results agree well with Fast and Freja observations of the nonlinear kinetic Alfven waves. An important feature of our study is the formation of rarefactive solitary structures. It has been shown that this result cannot be obtained with Maxwellian distribution and that it agrees well with the observations of Fast and Freja satellites.

Witness emittance growth caused by driver density fluctuations in plasma wakefield accelerators

We discovered a novel effect that can cause witness emittance growth in plasma wakefield accelerators. The effect appears in linear or moderately nonlinear plasma waves. The witness experiences a time-varying focusing force and loses quality during the time required for the drive beam to reach transverse equilibrium with the plasma wave. The higher the witness charge, the lower the emittance growth rate because of additional focusing of the witness by its own wakefield. However, the witness head always degrades, and the boundary between degraded and intact parts gradually propagates backward along the witness bunch.

Solutions of nonplanar KP-equations for dusty plasma system with GE-method

The propagation of three-dimensional nonlinear dust acoustic waves in a dusty plasma consisting of positive and negative dust grains as well as Boltzmann distributed electrons and ions is investigated. Using a reductive perturbation method, Cylindrical Kadomtsev-Petviashvili and Spherical Kadomtsev-Petviashvili equations, appropriate for describing the evolution of the system, are derived. The Generalized Expansion method is used to find the various solutions of the obtained nonlinear Kadomtsev-Petviashvili equations. New classes of triangular, hyperbolic solitary, rational, and Jacobi elliptical type solutions are obtained and graphically presented. It is found that the proposed dusty plasma model can support solitary waves with compressive and rarefactive potential pulses. Moreover, the effects of plasma parameters on this solitary wave structure are investigated. The current findings are applied to a cosmic-type plasma in different regions of space, viz. cometary tails, mesosphere, and Jupiter's magnetosphere as well as laboratory-type plasma such as low temperature experiments, where a dusty plasma with opposite polarity is dominant.

Nonlinear plasma waves in an electron gas

The nature of traveling wave solutions to equations of hydrodynamics of a 3D electron gas with parabolic dispersion law depends on whether the motion is subsonic or supersonic. Solitons representing localized depressions of the electrostatic potential and electron density are predicted to exist in the subsonic regime: at rest the solitons are dark while in motion they are grey. Two types of periodic waves are found in the supersonic regime: (i) smooth waves whose small amplitude limit is described by harmonic theory, and (ii) waves with sharp troughs and smooth crests of the potential with the electrons accumulating in the troughs.

Parametric Instability Driven by Weakly Trapped Particles in Nonlinear Plasma Waves.

This Letter describes a new parametric instability mechanism caused by a distribution f_{T} of particles trapped in the potential wells of a wave train. The mechanism explains a nonlinear instability in Trivelpiece-Gould (TG) waves, and it could also be a destabilizing factor in a range of nearly collisionless nonlinear plasma waves. The theory is compared to particle in cell simulations of TG waves.

On the nonlinear solitary and shock waves in Maxwellian multicomponent space plasma

Our objective is to study the nonlinear wave phenomena in a multicomponent plasma with Maxwellian electrons and ions. The main reason for this consideration is to exhibit the effects of dust charge fluctuations in plasma acoustic modes. Different aspects of nonlinear dynamics have been studied through the Korteweg-deVries (K-dV) equation (solitons) and the Burgers equation (shocks) derived by the reductive perturbation technique. A special method, known as the (G′/G) method, has been used for a solution. It predicts the different coherent features of various nonlinear waves successfully, and finally, their importance has been recognized in space plasmas. Evolutions have been shown with the input of appropriate typical plasma parameters to support our observations in space plasmas. All conclusions are in good agreement with the actual occurrences and could be of interest in furthering investigations in experiments and satellite observations in spaces. An important aspect of this exercise is a comparative study of K-dV and Burgers solutions in different plasma spaces.

Dipolar and chain of vortices in quantum plasmas with electrons exchange-correlation effects

The study of linear and nonlinear drift ion acoustic waves in a quantum plasma with electrons exchange correlation and pressure degeneracy effects is presented. A modified linear dispersion relation is obtained for an inhomogeneous degenerate plasma. In the nonlinear regime, dipolar and chain of vortices of drift ion waves are investigated. It is noticed that the amplitude of the dipolar vortices increases as the drift velocity decreases. The present results are compared with the previous studies. The relevance of the research work to laboratory and astrophysical plasmas is also pointed out.