Electrostatic solitary waves in an electron-positron pair plasma with suprathermal electrons

Abstract

The nonlinear propagation of electrostatic solitary waves is studied in a collisionless electronpositron pair plasma consisting of adiabatic cool electrons, mobile cool positrons (or electron holes), hot suprathermal electrons described by a κ distribution, and stationary ions. The linear dispersion relation derived for electrostatic waves demonstrates a weak dependence of the phase speed on physical conditions of positrons in appropriate ranges of parameters. The Sagdeev's pseudopotential approach is used to obtain the existence of electrostatic solitary wave structures, focusing on how their characteristics depend on the physical conditions of positrons and suprathermal electrons. Both negative and positive polarity electrostatic solitary waves are found to exist in different ranges of Mach numbers. As the positrons constitute a small fraction of the total number density, they slightly affect the existence domains. However, the positrons can significantly change the wave potential at a fixed soliton speed. The results indicate that the positive potential can greatly be grown by increasing the electron suprathermality (lower κ) at a fixed true Mach number. It is found that a fraction of positrons maintain the generation of positive polarity electrostatic solitary waves in the presence of suprathermal electrons in pair plasmas.

Theoretical analysis of planar and non‐planar electron ‐ acoustic shock waves in electron‐positron‐ion plasma

“…Furthermore, it is noticed that in comparison to cylindrical shock waves, the spherical shock wave moves faster. Furthermore, the shock wave amplitude decreases with an increase in the non‐extensive parameter q (non‐extensivity decreases) and cold to hot electron density ratio α , which is in agreement with the results of Danekhar. Because the ions are present in a small fraction and positrons have a long life, the major constituents of astrophysical and space plasma are electrons and positrons.…”

“…Numerical solution showed that the presence of non‐extensive particles, magnetic field, obliqueness, and temperature of different species have a great effect on the basic features of EASWs. Recently, Danekhar studied the non‐linear electrostatic waves in collisionless plasma consisting of cool positrons and superthermal electrons. Using Sagdeev's pseudopotential method, he investigated the characteristics of electrostatic waves with respect to physical conditions of superthermal electrons and positrons.…”

Electron beam-plasma interaction and electron-acoustic solitary waves in a plasma with suprathermal electrons

“…[54]). Alternatively, mobile cool positrons (or electron holes), together with suprathermal hot electrons, may support positive polarity electrostatic waves with the propagation speed comparable to the negative polarity electron-acoustic solitons [58].…”

“…However, the ion inertia propagates electrostatic waves in a slow-acoustic mode [54]. Thus, mobile positrons (or electron holes) may provide the inertia to have positive polarity in a fast-acoustic mode similar to the negatively polarized electronacoustic solitons [58]. Figure 5 shows the variation of the pseudopotential Ψ(φ) with the normalized potential φ, for different values of the positive normalized beam speed V b (keeping ρ h,c = 1, ρ b,c = 0.008, θ c,h = θ b,h = 0.01, κ = 4.0 and Mach number M = 0.9, all fixed).…”

Multi‐dimensional instability of electrostatic solitary waves in a warm multi‐ion dust plasma

“…[ 45 ] The nonlinear feature of electrostatic solitary waves was presented in a collisionless plasma consisting of stationary ions, mobile cool positrons, adiabatic cool electrons and hot κ distribution electrons. [ 46 ] Three‐dimensional modulational instability of electrostatic waves was described in e‐p‐i magnetoplasmas with κ distribution electrons. [ 47 ] Sagdeevs pseudopotential method is used to investigate small and arbitrary amplitude dust acoustic waves in a plasma which is constitute of kappa distributed electrons and ions as well as power law size distribution dust grains.…”