Nonplanar dust acoustic solitary and rogue waves in an ion beam plasma with superthermal electrons and ions

The propagation characteristics of dust acoustic solitary and rogue waves are investigated in an unmagnetized ion beam plasma with electrons and ions following kappa-type distribution in nonplanar geometry. The reductive perturbation method （RPM） is employed to derive the cylindrical/spherical Korteweg-de Vries （KdV） equation, which is further transformed into standard KdV equation by neglecting the geometrical effects. Using new stretching coordinates, nonlinear Schrrdinger equation （NLSE） has been derived from the standard KdV equation to study the different order rational solutions of dust acoustic rogue waves （DARWs）. The impact of various physical parameters on the characteristics of dust acoustic solitary waves （DASWs） is elaborated specifically in nonplanar geometry. Further, the effects of ion beam and superthermality of electrons/ions on the characteristics of DARWs are studied. The results obtained in the present investigation may be useful in comprehending a variety of phenomena in Earth＇s magnetosphere polar cap region where the presence of positive ion beam has been detected and also in other regions of space/astrophysical environments where dust along with superthermal electrons and ions exists.

Dust acoustic waves in collisional uniform dense magnetoplasma

In order to study the characteristics of dust acoustic waves in a uniform dense dusty magnetoplasma system, a nonlinear dynamical equation is deduced using the quantum hydrodynamic model to account for dust–neutral collisions. The linear dispersion relation indicates that the scale lengths of the system are revised by the quantum parameter, and that the wave motion decays gradually leading the system to a stable state eventually. The variations of the dispersion frequency with the dust concentration, collision frequency, and magnetic field strength are discussed. For the coherent nonlinear dust acoustic waves, new analytic solutions are obtained, and it is found that big shock waves and wide explosive waves may be easily produced in the background of high dusty density, strong magnetic field, and weak collision. The relevance of the obtained results is referred to dense dusty astrophysical circumstances.

Nonlinear Dust Acoustic Waves in a Magnetized Dusty Plasma with Trapped and Superthermal Electrons

In this work, the effects of superthermal and trapped electrons on the oblique propa- gation of nonlinear dust-acoustic waves in a magnetized dusty （complex） plasma are investigated. The dynamic of electrons is simulated by the generalized Lorentzian （k） distribution function （DF）. The dust grains are cold and their dynamics are simulated by hydrodynamic equations. Using the standard reductive perturbation technique （RPT） a nonlinear modified Korteweg-de Vries （mKdV） equation is derived. Two types of solitary waves; fast and slow dust acoustic solitons, exist in this plasma. Calculations reveal that compressive solitary structures are likely to propagate in this plasma where dust grains are negatively （or positively） charged. The properties of dust acoustic solitons （DASs） are also investigated numerically.

Dispersion relation of dust acoustic waves in metallic multi-walled carbon nanotubes

In this paper,a charged multi-walled carbon nanotube（MWCNT）,which is surrounded by charged nanoparticles,is modeled as a cylindrical shell of electron-ion-dust plasma.By employing classical electrodynamics formulations and the linearized hydrodynamic model,the dispersion relation of the dust acoustic wave oscillations in the composed system is investigated.We obtain a new low-frequency electrostatic excitation in the MWCNT,i.e.dust acoustic wave oscillations.

Characteristics of dust acoustic waves in dissipative dusty plasma in the presence of trapped electrons

The formation and propagation of nonlinear dust acoustic waves（DAWs） as solitary and solitary/shock waves in an unmagnetized, homogeneous, dissipative and collisionless dusty plasma comprising negatively charged micron sized dust grains in the presence of free and trapped electrons with singly charged non-thermal positive ions is discussed in detail. The evolution characteristics of the solitary and shock waves are studied by deriving a modified Korteweg–de Vries–Burgers（mKdV–Burgers） equation using the reductive perturbation method. The mKdV–Burgers equation is solved considering the presence（absence） of dissipation. In the absence of dissipation the system admits a solitary wave solution, whereas in the presence of dissipation the system admits shock waves（both monotonic and oscillatory） as well as a combination of solitary and shock wave solutions. Standard methods of solving the evolution equation of shock（solitary） waves are used. The results are discussed numerically using standard values of plasma parameters. The findings may be useful for better understanding of formation and propagation of waves in astrophysical plasma.

Dust acoustic rogue waves of fractional-order model in dusty plasma

In this paper,the fractional-order model is used to study dust acoustic rogue waves in dusty plasma.Firstly,based on control equations,the multi-scale analysis and reduced perturbation method are used to derive the(3+1)-dimensional modified Kadomtsev–Petviashvili(MKP)equation.Secondly,using the semi-inverse method and the fractional variation principle,the(3+1)-dimensional time-fractional modified Kadomtsev–Petviashvili(TF-MKP)equation is derived.Then,the Riemann–Liouville fractional derivative is used to study the symmetric property and conservation laws of the(3+1)-dimensional TF-MKP equation.Finally,the exact solution of the(3+1)-dimensional TF-MKP equation is obtained by using fractional order transformations and the definition and properties of Bell polynomials.Based on the obtained solution,we analyze and discuss dust acoustic rogue waves in dusty plasma.

Modeling of nonlinear envelope solitons in strongly coupled dusty plasmas:Instability and collision

Modeling of instability and collision of nonlinear dust-acoustic（NDA） envelope solitons in strongly coupled dusty plasmas（SCDPs） is theoretically investigated. The SCDPs consists of strongly correlated negatively variable-charged dust grains and weakly correlated Boltzmann electrons and ions. Using the derivative expansion perturbation technique, a nonlinear Schr dinger-type（NLST） equation for describing the propagation of NDA envelope solitons is derived. Moreover,the extended Poincar′e–Lighthill–Kuo（EPLK） method is employed to deduce the analytical phase shifts and the trajectories after the collision of NDA envelope solitons. In detail, the results show that both modulation instability and phase shift after collision of NDA envelope solitons will modify with the increase in the effects of the viscosity, the relaxation time, and the dust charge fluctuation. Crucially, the modeling of dust-acoustic envelope solitons collision, as reported here, is helpful for understanding the propagation of NDA envelope solitons in strongly coupled dusty plasmas.

Breathing Modes in Dusty Plasma

Acoustic breathing modes of dusty plasmas have been investigated in a cylindrical system with an axial symmetry. The linear wave solution and a 'dispersion' relation were derived. It was found that in an infinite area, the mode is reduced to a 'classical' dust acoustic wave in the region away from the center. If the dusty plasma is confined in a finite region, however, the breathing (or heart-beating) behavior would be found as observed in many experiments.

Lower order three-dimensional Burgers equation having non-Maxwellian ions in dusty plasmas

The dust acoustic（DA） shock wave with dust charge fluctuations, non-Maxwellian ions, and non-isothermal electrons is studied theoretically. The perturbation technique is employed to derive the lower order three-dimensional（3D） Burgers equation, and shock wave solution is explored by the tan-hyperbolic method. The effects of flat trapped and trapped electron distributions in the presence of Maxwellian and non-Maxwellian ions on characteristics shock waves are observed. The temperature ratio of non-Maxwellian ion temperature and non-isothermal electron temperature is found to play an important role in forming the shock-like structure.