Nonlinear ion‐acoustic cnoidal wave in electron‐positron‐ion plasma with nonextensive electrons

Abstract

Effects of plasma nonextensivity on the nonlinear cnoidal ion-acoustic wave in unmagnetized electron-positron-ion plasma have been investigated theoretically. Plasma positrons are taken to be Maxwellian, while the nonextensivity distribution function was used to describe the plasma electrons. The known reductive perturbation method was employed to extract the KdV equation from the basic equations of the model. Sagdeev potential, as well as the cnoidal wave solution of the KdV equation, has been discussed in detail. We have shown that the ion-acoustic periodic (cnoidal) wave is formed only for values of the strength of nonextensivity (q). The q allowable range is shifted by changing the positron concentration (p) and the temperature ratio of electron to positron ( ). For all of the acceptable values of q, the cnoidal ion-acoustic wave is compressive. Results show that ion-acoustic wave is strongly influenced by the electron nonextensivity, the positron concentration, and the temperature ratio of electron to positron. In this work, we have investigated the effects of q, p, and on the characteristics of the ion-acoustic periodic (cnoidal) wave, such as the amplitude, wavelength, and frequency. KEYWORDScnoidal wave, electron-positron-ion plasma, ion-acoustic nonlinear wave, plasma nonextensivity, solitary wave INTRODUCTIONPlasma is mainly the science of universe, new accelerators, and new source of energy. Furthermore, there are many other applications of plasma that is penetrating into the technology of our ordinary life. [1,2] Plasma is a multimode medium. Depending on plasma species and condition, as well as plasma energy, a wide range of longitudinal or transverse modes in cnoidal or soliton form may generate in plasma medium. Some of them may be observed in linear regime, but there are a large number of plasma modes that will appear after taking the nonlinearity into account. Because of its high energy, the nonlinear phenomena play an essential role in plasma medium.Normal plasmas comprise of electrons, ions, and neutral particles. In the case of high-energy plasma, positrons will be produced in the medium due to pair production phenomena. The electron-positron-ion (e-p-i) plasma has an important role in the understanding of the plasmas in the early universe, [3,4] in active galactic nuclei, [5] in pulsar magnetospheres, [6,7] and in the solar atmosphere.[8] It is well known that when positrons are introduced into e-i plasma, the response of the plasma changes significantly. The presence of positrons has some application in plasma. For instance, they can be used to probe particle transport in tokamaks, and since they have sufficient lifetime, the two-component (e-i) plasma becomes three-component (e-p-i) plasma. [9][10][11][12][13] Most of the astrophysical plasmas also contain positrons in addition to electrons and ions. During the last decade, e-p-i plasma has attracted the attention of several authors. They have studied the linear and nonlinear wave propagation in e-p-i plasmas using different models. [14][1...

Electrostatic cnoidal waves and soliton structures in multi‐ions plasmas

“…Stasiewicz found the wave solution in the form of train of solitons for nonlinear electrons' and ions' inertial waves in an anisotropic plasma. The ion‐acoustic nonlinear periodic waves in electron–positron–ion (EPI) plasma , two electrons' plasma, and PI plasma have also been investigated. According to our knowledge, the nonlinear periodic waves in multi‐ion plasmas have not been studied yet.…”

Ion‐ and positron‐acoustic solitons in magnetized dusty plasma with q‐non‐extensive electron and positron velocity distribution

“…e-p-i plasmas are found in many astrophysical environments such as the magnetosphere of pulsars, in active galactic nuclei, in early universe, in the regions of the accretion discs surrounding the central black holes, at the centre of our galaxy, in the polar regions of neutron stars, and in the solar atmosphere. [6,35] They were first predicted by Tonks and Langumir on the basis of the two-fluid model in 1929. Positrons can be generated as a result of the collision of runaway electrons with plasma ions and thermal electrons.…”

“…A great deal of research has been carried out to study e-p-i plasmas. [31,[38][39][40] There have been many studies on the non-linear wave propagation in e-p-i plasmas because of its importance not only in plasma astrophysics [24,35,38,[41][42][43][44] but also in laboratory experiments in tokamak plasmas. Space plasma observations clearly indicate the existence of e-p-i plasmas that are far away from their thermodynamic equilibrium.…”

“…[26,[31][32][33][34] IASWs are low-frequency longitudinal plasma oscillations that form under the low-frequency perturbations in a plasma medium. [6,35] They were first predicted by Tonks and Langumir on the basis of the two-fluid model in 1929. [36] The non-linear theory of IASWs was first considered by Sagdeev and Leontovich, who studied their basic features using a mechanical analogy.…”

“…[32] The first experimental observation of IA solitons was reported by Ikezi et al [37] The non-linear dynamics of a small but finite amplitude IA solitons can be governed by the well-known Korteweg-de Vries (KdV) equation, which predicts the existence of solitons, as was shown for the first time by Washimi and Taniuti. [31,[38][39][40] There have been many studies on the non-linear wave propagation in e-p-i plasmas because of its importance not only in plasma astrophysics [24,35,38,[41][42][43][44] but also in laboratory experiments in tokamak plasmas. [45] The presence of external magnetic fields in plasmas plays an important role in the dynamics of non-linear waves.…”