Effect of Pressure Anisotropy on Nonlinear Periodic Waves in a Magnetized Superthermal Electron-Positron-Ion Plasma

Abstract

The propagation properties of electrostatic cnoidal waves (periodic waves) and solitons are studied in a magnetized electron-positron-ion (EPI) plasma bearing ion pressure anisotropy and superthermality. In a two-dimensional geometry, we considered the ions to be warm having pressure anisotropy due to magnetic field. The anisotropic ions are modeled via double adiabatic Chew-Golberger-Low (CGL) theory and the lighter species (electron and positron) are following kappa distributions. A Korteweg-de Vries (KdV)-type equation is derived by employing reductive perturbation technique, and obtained the nonlinear periodic waves solutions with appropriate boundary conditions. The anisotropy in the ion thermal pressure relative to the external magnetic field (different values in parallel and perpendicular directions) have significant effects on the characteristics of cnoidal waves. It is observed that by increasing the ion parallel and perpendicular pressure (keeping the relative anisotropy) tends to reduce the wavelength of the cnoidal wave structure, while the amplitude tends to increase. The influence of superthermality of electron and positron, the positron content and strength of the external magnetic field on the cnoidal waves are studied in detail. Furthermore, phase portrait analysis is carried out and traced out the equilibrium points around which nonlinear periodic waves can be formed. The saddle points which correspond to the homoclinic orbits are also shown. The investigation can be useful in exploring the nonlinear wave dynamics in both laboratory and space plasma where ion pressure anisotropy and superthermality exist.

On the existence and formation of small amplitude electrostatic double‐layer structure in nonthermal dusty plasma

“…Motivated by these events, the nonequilibrium plasmas are modelled via the nonthermal [13][14][15] or kappa type distributions. [16][17][18] This nonthermal, also known as Cairns distribution function was introduced in the ref. 13 by Cairns et al and showed that the presence of nonthermal electrons and cold ions can support the simultaneous existence of solitary waves.…”

Nonlinear periodic coupled Alfvén and ion-acoustic wave structures in plasmas

“…The IA cnoidal wave structures have already been investigated in pair-ion (PI) plasma [41], electron-positron-ion (EPI) plasma [42,43] and two electrons plasma [44]. Recently, Rehman et al [45] theoretically studied the magneto-acoustic cnoidal wave structures in multi-ion plasmas, whereas Khan et al [46] investigated the effects of pressure anisotropy on IA cnoidal wave structures in a magnetized EPI plasma. The magnetosonic cnoidal waves and solitons are recently investigated in a magnetized dusty plasma [47].The authors have found the positive potential magnetosonic cnoidal and soliton structures in a magnetized dusty plasma.…”