Dust-acoustic Mode Research Articles

Matter transport as fundamental property of acoustic solitons in plasma

A theoretical study of the phenomenon of unidirectional transport of charged particles by acoustic-type solitons in plasma without the magnetic field is presented. Using a one-dimensional ion-acoustic soliton as an example, it is shown that the transport of charged particles is a fundamental property of classical solitons, which cannot be neglected at small wave amplitudes. The analysis is based on the hydrodynamic model using the Sagdeev pseudopotential and the KdV equation. A brief generalization of the results to electron- and dust-acoustic modes is also discussed.

Effect of trapping and reflection on dust acoustic solitary waves in nonthermal opposite polarity dust plasmas

The study of resonant wave-particle interactions (WPIs) is crucial in plasma systems where charged plasma particles interact via long-range electromagnetic waves. Our research focuses on exploring the impact of trapping and reflection, along with the superthermality of Kappa resonance electrons and ions, on the characteristics of dust acoustic waves (DAWs) in opposite polarity dust plasma (OPDP). Both linear and non-linear analyses were conducted. Two distinct types of dust acoustic modes, namely fast and slow, have been observed in the linear regime of two different instances of WPIs. Moving on to the non-linear regime, the Schamel KdV (SKdV) equation has been derived using the reductive perturbation technique. In both cases, a stationary solution in the form of a dust acoustic double-layer wave (DADLW) has been successfully obtained. Our findings are highly relevant to astrophysical plasma environments with non-thermal trapped and reflected particles.

Analytical soliton solutions and wave profiles of the (3+1)-dimensional modified Korteweg–de Vries–Zakharov–Kuznetsov equation

In this research paper, the improved generalized Riccati equation mapping (IGREM) method is employed to get analytical soliton solutions of (3+1)-dimensional modified Korteweg–de Vries–Zakharov–Kuznetsov (mKdV-ZK) equation. By giving appropriate parametric values, we obtain soliton solutions of various types, such as kink soliton, singular soliton, and periodic-singular soliton. The description provided in physical variables allows for the study of genuine multispecies plasmas, plasma models, and frequency regimes. These solutions are essential in illuminating several physical phenomena in engineering and other applied sciences. In addition, 3D and 2D graphs of some selected solutions are sketched for the best physical characterization of the obtained results. This method can also be implemented in many non-linear equations in contemporary research areas. Comparison with previous studies shows that the discovery of singular soliton is novel. Therefore, our research represents a significant advancement in the field and contributes to expanding the knowledge regarding soliton behavior. The applications of this study include electron and ion-acoustic modes in regular plasmas with hot Boltzmann electron species, as well as ion and dust-acoustic modes, depending on the specific modeling of the heavier components.

Dust acoustic wave properties in varying discharge volumes

Properties of self-excited dust acoustic waves under the influence of active compression of the dust particle system were experimentally studied in the laboratory and under microgravity conditions (parabolic flight). Ground based laboratory experiments clearly show that wave properties can be manipulated by changing the discharge volume, its aspect ratio, and thus the dust particle density. Complementary experiments under microgravity conditions, performed to exclude the effects of gravity inflicted sedimentation and anisotropic behavior, were less conclusive due to residual fluctuations in the planes acceleration indicating the need for a better microgravity environment. A theoretical model, using plasma parameters obtained from particle-in-cell simulations as input, supports the experimental findings. It shows that the waves can be described as a new observation of the dust acoustic mode, which demonstrates their generic character.

Effect of Tsallis–Gurevich distributed ions on nonlinear dust‐acoustic oscillations in collisionless nonextensive plasma

AbstractBoth linear and weakly nonlinear dust‐acoustic (DA) solitons propagation are revisited in the presence of adiabatically trapped‐nonextensive ions. A physically relevant distribution (called Tsallis‐Gurevich ions distribution) is outlined here for the first time. The effect of particle trapping has been taken into account, resulting in a new expression for the ion density. The role a background ion nonextensivity may play on the main proprieties (viz., dispersion relation and soliton's profile) of DA mode, inherent to space dusty plasma, is then analysed. In the q > 1 case, we have shown that as the nonextensive character of trapped ions increases in the plasma, the potential pulse amplitude increases while its width is narrowed. The modifications prompted by the presence of adiabatically trapped‐nonextensive ions on both DA energy and solitary wave's electric field are also analysed. Interestingly, we have found that DA soliton energy increases as the ions evolve far away from their Maxwellian extensive trapping. Also, it is found that, for q > 1, the stronger the inter‐ions correlation, the stronger the electric field. Our investigation, motivated by space and laboratory plasma observations of plasmas containing non‐Maxwellian particles alongside trapped particles, may complement and provide new insight into previously published works dealing with solitary waves in plasma.

Nonlinear propagation of dust-acoustic modes in a dusty plasma with the Kappa-Cairns polarization force effects

In this paper, the influence of Kappa-Cairns polarization force on solitary and periodic dust-acoustic (DA) waves is studied in a non-uniform dusty plasma containing negatively charged dust grains, Maxwellian electrons, and the Kappa-Cairns distributed ions. It is observed that in the presence of Kappa-Cairns distributed ions, the magnitude of the polarization force first increases as the spectral index increases and then decreases. The nonlinear Korteweg-de-Vries (K-dV) equation is obtained employing the reductive perturbation technique. The effects of polarization parameter (), Kappa-Cairns distribution parameters ( and ), and different ratios of ion to electron number densities () are investigated on the characteristics of DA solitary waves. We observed that the variations in the phase speed, amplitude, and width of DA solitons in the presence of the Kappa-Cairns polarization force are considerably different for case with respect to . The bifurcation theory of planar dynamical systems is also applied to investigate the existence of the solitary/periodic traveling wave in this plasma model. The phase portrait topology is illustrated for the K-dV equation. It is found that polarization force and other plasma parameters have a vital role in the traveling wave structures.

Modulational Interaction in a Dusty Plasma of Meteoroid Wakes

This is a study of the possible modulational instability of electromagnetic waves in meteoroid wakes associated with the dust acoustic mode at altitudes of 80–120 km, which is a linear stage of modulational interaction. The parameters of meteoroid wakes at different altitudes in the Earth’s ionosphere are considered. It is shown that the charging of dust particles of meteoric matter creates conditions for the occurrence of dust acoustic waves. Dust acoustic disturbances are excited due to the modulational instability of electromagnetic waves from the meteoric trail. The influence of neutrals on the development of modulational interaction is taken into account. The concentration of neutrals in meteoric wakes is higher than the concentration of neutrals in the Earth’s ionosphere. It has been found that the condition for the excitation of a dust acoustic wave is satisfied for the typical parameters of dusty plasma of meteoroid wakes at altitudes of 100–120 km. Due to collisions between dust and neutrals, the development of modulation instability is suppressed at altitudes of 80–90 km, while inelastic collisions of neutrals with electrons and ions do not affect the development of modulational instability. The modulational instability of electromagnetic waves can explain the occurrence of low-frequency noise during the passage of meteoric bodies in a frequency range characteristic of dust acoustic waves. It is shown that the modulation instability has time to develop for characteristic temperatures and particle concentrations in meteoroid wakes. Equations for the charging of dust particles in meteoroid wakes are given. It has been found that the dust is positively charged, both in the daytime and at night, due to intense emission currents from the surface of dust particles.

Nonlinear dust-acoustic modes in homogeneous dusty plasmas: bifurcation analysis

Different nonlinear dynamical behavior of dust-acoustic modes of a homogeneous plasma are examined. The plasma composed of negatively charged dust grains and nonextensive distribution electrons and ions. The evolution of the system is investigated using a 3-dimensional nonlinear Schrodinger (3D-NLS) equation. Different methods are used to explore the possible solutions of 3D-NLS equation using a bifurcation analysis and factorization method to obtain periodic, shocklike and explosive waves. Furthermore, rogue wave solution of the 3D-NLS equation is obtained to investigate the dependence of rogue wave profile on nonextensivity parameters. The present investigation can be relevance to the electrostatic structures in various dusty plasmas, such as Saturn’s E-ring.

Suppression of the Kelvin–Helmholtz instability due to polarization force in nonuniform magnetized sheared dusty plasmas

The Kelvin–Helmholtz (K–H) instability in a magnetized nonuniform velocity sheared dusty plasma is investigated accounting for the effects of dust polarization force due to inhomogeneity in background plasma number densities. A three-component fluid model for dusty plasma is formulated considering Boltzmann electron/ion fluids and flowing magnetized dust fluids whose dynamics are affected due to the presence of dust polarization force. A dispersion relation for the K–H instability is derived by applying normal mode analysis on the linearized perturbation equations of the system. It is found that the polarization parameter dependent dust acoustic mode significantly modifies the dispersion relation of the K–H instability. The critical shear required to excite the K–H instability (S > Scrit) decreases with an increase in the dust polarization parameter and dust cyclotron frequency. The growth rate of the K–H instability is observed to be suppressed due to the presence of the dust polarization parameter. The results have been discussed for experimental magnetized dusty plasmas, which shows that under considered parametric limits, one cannot ignore the presence of dust polarization force on the excitation of the K–H instability in dusty plasmas. The astrophysical consequences are also discussed in Saturn’s E-ring in the limiting case of varying dust grain size.

Linear propagation of dust acoustic modes in the presence of an electron beam

The physical and optical properties of plasmas are depended on dynamics of species in the discharge volume. Then, the presence of an electron beam, as a separate component, in a dusty plasma can modify the plasma structures through altering the discharge parameters. In this report, the linear propagation of acoustic modes in a collisionless dusty plasma contains electrons, ions and charged dust grains is investigated in the presence of an electron beam. Our analysis indicates that the electron beam can modify the dispersion relations of dust acoustic modes which resulted different data transportation in dusty plasmas. The obtained results are also examined for negative and positive charged dust grains with different number densities. The charge of dust grains represents an important role in the dynamics of the low frequency waves. Additionally, our findings reveal that the propagation of acoustic waves in dusty plasmas can be controlled by adjusting the electron number density of the beam and the cathode potential. Lastly, we obtian the destabilizing effects, originated from dust charge fluctuation, by reconsidering the dispersion relations of both dust acoustic modes.

On the possibility of dust acoustic waves over sunlit lunar surface

ABSTRACTThe photoelectron sheath and floating fine positively charged dust particles constitute two-component dusty plasma in the sunlit lunar regolith’s vicinity. By including the charge fluctuation into photoelectron–dust dynamics, the lunar exospheric plasma is proposed to support the propagation of long-wavelength dust acoustic (DA) modes. Using the standard approach based on the dynamical equations for continuity, momentum, plasma potential, and dust charging along with Fowler's treatment of photoemission and non-Maxwellian nature of the sheath photoelectrons, the wave dispersion is derived. The dust charge variation modifies the usual DA wave dispersion and excites the ultralow frequency modes that propagate with sufficiently low phase speed. Such ultralow frequency modes are predicted as pronounced for smaller values of dust charge and sheath potential. The DA wave dispersion is also depicted as sensitive to the photoelectrons’ energy distribution within the sheath. The quantitative estimates suggest that the nominal exospheric plasma may exhibit DA waves propagating with frequencies of the order of unity.

Electrophonic noises from meteors and dust acoustic modulational perturbations

The article discusses dusty plasmas processes in the Earth’s ionosphere associated with the passages of meteoroids and the spread of the meteor tail. Mechanisms explaining the occurrence of electrophonic noises recorded simultaneously with the passage of meteor bodies are suggested for extremely low frequencies range. It is explained by modulational instability of electromagnetic waves from meteor associated with the dust acoustic mode with characteristic frequencies 0.03–60 Hz. As electromagnetic waves propagate in the dusty plasmas of the meteor tail or in the dusty ionospheric plasmas, dust acoustic waves are excited as a result of the development of modulational instability of electromagnetic waves at characteristic frequencies and as a result, the electromagnetic waves become modulated. At the surface, these perturbations can be converted into sound waves by means of receivers. The growth rates of modulational instability at which the modulational excitation of extremely low-frequency dust acoustic disturbances occur are calculated. The conditions of the development of modulational instability are given. The correlation between observations of ionospheric radio noises and passages of meteors is noticed. Observed data of electrophonic noises include discussing range of frequencies 0.03–60 Hz.

Nonlinear dispersion relation for dust-acoustic waves in complex plasmas.

Nonlinear dispersion relation for the finite-amplitude dust acoustic modes is obtained taking into account resonant particle trapping in the wave. The kinetic model predicts a frequency shift scaling ∝sqrt[ϕ] relative to the linear dispersion relation with ϕ being the wave amplitude of the electrostatic potential. The species contributions to the nonlinear frequency shift have opposite sign: positive for trapped electrons and ions and negative for particles. It is shown that the relative importance of these contributions depends on the electron-to-ion or particle temperature ratio, particle charge, and Havnes parameter. In typical complex plasma experiments, the kinetic frequency shift is dominated by the positive ion contribution. As a result, the nonlinear modification of the dispersion relation affects the wave dispersion properties and may provide the acoustic-like behavior to the wave number domain kλ_{Di}∼1.

Soliton Currents (Review)

The theoretical and experimental results on plasma currents induced by acoustic-type solitons are generalized. Ion, electron, and dust-acoustic modes in plasma without magnetic field are considered in detail. It is shown that the generation of pulsed plasma currents with a significant direct component is an inherent property of solitons. The basic properties of soliton currents are established.

Dust-acoustic Rogue Waves in Four-Component Plasmas

A theoretical investigation has been made on modulational instability (MI) and dust-acoustic (DA) rogue waves (DARWs) in a four-component dusty plasma medium containing inertial negatively charged massive heavy (light) cold (hot) dust grains as well as super-thermal electrons and non-thermal ions. The reductive perturbation method is used to derive the nonlinear Schrodinger equation, and two types of modes, namely fast and slow DA modes, have been observed. The conditions for the MI and the formation of associated DARWs are found to be significantly modified by the effects of non-thermality of ions (α), super-thermality of electrons (κ), density-ratio of non-thermal ion to cold dust ($${{\mu }_{i}}$$), and mass-ratio of cold dust to hot dust (σ), etc. The implications of our current investigation in space and laboratory plasmas are briefly discussed.

Polarized Debye Sheath in Degenerate Plasmas**Support from SERB, Govt. of India for a Research Project with sanction order No. CRG/2018/004475

The force on a charged dust grain in a plasma due to polarization of thermal ions and degenerate electrons around the grain is derived in the limits of weakly relativistic and ultra-relativistic degeneracy of electrons. It is found that in both these cases, the magnitude of the polarization force is enhanced compared to that in classical plasmas. The influence of this force on dust-acoustic (DA) modes is examined and discussed. It is shown that the DA wave frequency in degenerate plasmas is significantly reduced compared to the classical DA mode.

Streaming instability of dust-acoustic mode with helical wavefronts

Making use of the kinetic approach for plasma species, the electrostatic twisted dust-acoustic (DA) waves are studied in a collisionless unmagnetized multi-component dusty plasma consisting of electrons, singly ionized positive ions and charged massive dust grains. The Vlasov-Poisson equations are coupled together to obtain a generalized response function by using the Laguerre-Gaussian (LG) perturbed electrostatic potential and distribution function in the paraxial limit. The dispersive properties and growth rate instability of twisted DA waves are examined with distinct OAM states in a multi-component dusty plasma. Various significant modifications associated with the real wave frequency and growth rate are shown with respect to twist parameter and dust concentration. It is examined that dust concentration enhances the growth rate of twisted DA waves, whereas an increase in twist parameter reduces the growth rate instability. The excitation of twisted DA mode is also found to enhance with streaming speed of inertialess electrons. Our results may be useful for particle transport and trapping phenomena due to wave excitation in laboratory dusty plasmas.

A Nonlocal Theory of Current-Driven Low-Frequency Modes in a Magnetized Strongly Coupled Collisional Dusty Plasma

The nonlocal theoretical model developed to observe current-driven low-frequency electrostatic modes in a collisional magnetized strongly coupled dusty plasma, in the strongly coupled kinetic regime ωτ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ≫ 1 (i.e., wave frequency is much larger than the dust particle relaxation time) led to a new set of equations for dispersion relation, frequency, and the growth rate. The theoretical investigations on a cylindrical magnetized strongly coupled dusty plasma led to a current driven ion dust hybrid like longitudinal dust wave propagating nearly along radial direction and a peculiar transverse shear dust wave mode along axial direction. Dispersion properties of both longitudinal dust acoustic modes and transverse shear modes are modified in the presence of ion and dust currents and the effective perpendicular wave number provided by finite geometry of strongly coupled magnetized dusty plasma. The magnetic field has a destabilizing effect on the growth of longitudinal wave modes, while the dependence of transverse modes on the strength of magnetic field is not prominent. Transverse shear modes are characterized as the short wavelength modes with a long wavelength cutoffs. A comparison of nonlocal effects with local effects shows that in bounded magnetized strongly coupled dusty plasmas, the longitudinal wave modes need a large magnetic field and weak collisional regime to support the excitation of dust wave modes, whereas the transverse modes are a consequence of viscous and collisional damping.

Modulated Dust-Acoustic Wave Packets in an Opposite Polarity Dusty Plasma System

The nonlinear propagation of the dust-acoustic bright and dark envelope solitons in an opposite polarity dusty plasma (OPDP) system (composed of non-extensive q-distributed electrons, iso-thermal ions, and positively as well as negatively charged warm dust) has been theoretically investigated. The reductive perturbation method (which is valid for a small, but finite amplitude limit) is employed to derive the nonlinear Schrödinger equation. Two types of modes, namely, fast and slow dust-acoustic (DA) modes, have been observed. The conditions for the modulational instability (MI) and its growth rate in the unstable regime of the DA waves are significantly modified by the effects of non-extensive electrons, dust mass, and temperatures of different plasma species, etc. The implications of the obtained results from our current investigation in space and laboratory OPDP medium are briefly discussed.

Generation of rogue waves in space dusty plasmas

The basic features of dust-acoustic (DA) waves (DAWs) in a four component dusty plasma system (containing inertial cold and hot dust grains and inertialess non-extensive ions and electrons) have been theoretically investigated by deriving the nonlinear Schrödinger equation. The analytic analysis under consideration demonstrates two types of modes, namely, fast and slow DA modes. The unstable domain, which can be recognized by the critical wave number (kc), gives rise to the DA rogue waves (DARWs). It is observed that the amplitude and width of the DARWs are significantly modified by various plasma parameters. The present results should be useful in understanding the conditions for modulational instability of DAWs and generation of DARWs in Saturn F-rings.