Formation of large-amplitude double layers in a dusty plasma whose constituents are electrons, ions, warm dust grains and positive ion beam are studied using Sagdeev’s pseudopotential technique. Existence of double layers is investigated. It is found that both the temperature of dust particles and ion beam temperature play significant roles in determining the region of the existence of double layers.

In this paper, we study the head-on collision between two dust-ion-acoustic (DIA) solitons in quantum electron-dust-ion plasma. Using the extended Poincaré–Lighthill–Kuo (PLK) method, we obtain the Korteweg–de Vries (KdV) equations, the phase shifts and the trajectories after the head-on collision of the two DIA solitons. We investigate the effect of quantum diffraction parameters for electrons and ions $(H_{e}, H_{i})$, the Fermi temperature ratio $(\sigma)$ and the dust charged number density $(n_{\text{d0}})$ on the phase shifts. Different values of $\mu = z_{\text{d0}}(n_{\text{d0}}/n_{\text{i0}})$ and $\mu_{\text{d}} = z_{\text{d0}}(m_{\text{i}}/m_{\text{d}})$ are taken to discuss the effects on phase shifts, where $z_{\text{d0}}$ denotes the dust charge number, $n_{\text{j0}}$represents the equilibrium number density and $m_{j}$ is the mass of the jth species ($j = e, i , d$ for electrons, ions and dust particles, respectively). It is observed that the phase shifts are significantly affected by the plasma parameters.

The properties of nonplanar (cylindrical and spherical) dust-acoustic solitary waves (DASWs) in an unmagnetized, collisionless three-component dusty plasma, whose constituents are negatively charged cold dust fluid, superthermal/non-Maxwellian electrons (represented by kappa distribution) and Boltzmann distributed ions, are investigated by deriving the modified Gardner (MG) equation. The well-known reductive perturbation method is employed to derive the MG equation. The basic features of nonplanar DA Gardner solitons (GSs) are discussed. It is seen that the properties of nonplanar DAGSs (positive and negative) significantly differ as the value of spectral index 𝜅 changes.

We investigate the face-to-face collision between multisolitons in spin-1/2 quantum plasma. It is studied in the framework of the model proposed by Marklund et al in {\it Phys. Rev.} E 76, 067401 (2007). This studyis done with the help of the extended Poincare–Lighthill–Kno (PLK) method. The extended PLK method is also used to obtain two Korteweg–de Vries (KdV) equations and the phase shifts and trajectories during the head-oncollision of multisolitons. The collision-induced phase shifts (trajectory changes) are also obtained. The effects of the Zeeman energy, total mass density of the charged plasma particles, speed of the wave and the ratio of the sound speed to Alfvén speed on the phase shifts are studied. It is observed that the phase shifts are significantly affected by all these parameters.

The characteristics of ion-acoustic solitary waves in rotating, weakly relativistic, magnetised and collisionless plasma system comprising electron, positron and ion (EPI) under a periodic external force, whose constituents electron and positron obey Boltzmann distribution, are investigated by deriving forced Zakharov–Kuznetsov (FZK) equation. FZK equation is constructed using reductive perturbation technique (RPT) which is based on multiple-scale analysis of dependent variables. The effects of physical parameters such as the ratio of temperature of electron and positron, the strength of external periodic force, positron concentration in electron background, ion temperature and magnetic field on the analytical solitary wave solution of FZK equation are observed. It is seen that the behaviours of ion-acoustic wave are significantly affected due to the presence of positron and the periodic external forces. The results of this work may be applied when the above-mentioned plasma environment is found in laboratory as well as in space.

The purpose of this article is to derive a class of multi-soliton solutions of the Burgers equation employing Darboux transformation with the help of the Lax pair. By means of an effective transformation, the Burgers equation is reduced to a suitable form, and accordingly, the Lax pair of the said equation is derived utilisingthe Ablowitz–Kaup–Newell–Segur (AKNS) approach. Thus, the integrability of the Burgers equation is confirmed. To find an effective solution for the Burgers equation, for the first time, we apply the Darboux transformation through the Lax pair and explore new types of one-soliton solutions and two-soliton solutions of the Burgers equation. These solutions provide some new features of the Burgers equation. To the best of our knowledge, this is the first studyin which a parabolic type of structure is found in the Burgers system. Moreover, taking these solutions as the seed solution, higher-order multi-soliton solution can also be generated. Finally, some important three-dimensional plotsof the wave solutions are presented to visualise the dynamics of the model.