On the existence and stability of electrostatic structures in non-Maxwellian electron-positron-ion plasmas

Gina Williams, I. Kourakis

Research output: Contribution to journalArticle

18 Citations (Scopus)
228 Downloads (Pure)

Abstract

Electrostatic solitary waves in plasmas are the focus of many current studies of localized electrostatic disturbances in both laboratory and astrophysical plasmas. Here, an investigation of the nonlinear dynamics of plasma evolving in two dimensions, in the presence of excess superthermal background electrons and positrons, is undertaken. We investigate the effect of a magnetic field on weakly nonlinear ion acoustic waves. Deviation from the Maxwellian distribution is effectively modelled by the kappa model. A linear dispersion relation is derived, and a decrease in frequency and phase speed in both parallel and perpendicular modes can be seen, when the proportion of positrons to electrons increases. We show that ion acoustic solitary waves can be generated during the nonlinear evolution of a plasma fluid, and their nonlinear propagation is governed by a Zakharov-Kuznetsov (ZK) type equation. A multiple scales perturbation technique is used to derive the ZK equation. The solitary wave structures are dependent on the relation between the system parameters, specifically the superthermality of the system, the proportion of positron content, magnetic field strength, and the difference between electron and positron temperature. The parametric effect of these on electrostatic shock structures is investigated. In particular, we find that stronger superthermality leads to narrower excitations with smaller potential amplitudes. Increased positron concentration also suppresses both the amplitude and the width of solitary wave structures. However, the structures are only weakly affected by temperature differentials between electrons and positrons in our model.
Original languageEnglish
Article number122311
JournalPhysics of Plasmas
Volume20
Issue number12
DOIs
Publication statusPublished - 01 Dec 2013

Fingerprint Dive into the research topics of 'On the existence and stability of electrostatic structures in non-Maxwellian electron-positron-ion plasmas'. Together they form a unique fingerprint.

  • Projects

    R1353CPP: Fluid theory for laser-plasma interactions

    Kourakis, Y.

    01/08/201030/04/2013

    Project: Research

    Cite this