Eur. Phys. J. D 49, 373-377 (2008)
https://doi.org/10.1140/epjd/e2008-00184-1

Solitary wave propagation in quantum electron-positron plasmas

Department of Mathematics, Siksha Bhavana, Visva-Bharati University, Santiniketan 731 235, India

Corresponding author: ^a apmisra@visva-bharati.ac.in

Received: 30 April 2008
Revised: 5 August 2008
Published online: 3 October 2008

Abstract

Existence of large amplitude stationary solitary wave structures in an unmagnetized electron-positron (e-p) plasma is studied using a quantum hydrodynamic (QHD) model that includes the quantum force (tunnelling) associated with the Bohm potential and the Fermi-dirac pressure law. It is found that in a quasi-neutral pair (e-p) plasma, where the dispersion is only due to the the quantum tunnelling effects, the large amplitude stationary solitary structure exists only when the normalized Mach speed, . Such solitary structures do not exist in absence of the Bohm potential term in an unmagnetized quasineutral pair (e-p) plasma. The system is shown to support only rarefactive stationary solitary waves. For such waves the amplitude, being independent of the quantum parameter H (the ratio of the electron plasmon to electron Fermi energy), decreases with the Mach number M, whereas the width increases with both M and H. The present theory is applicable to analyze the formation of localized coherent solitary structures at quantum scales in dense astrophysical objects as well as in intense laser fields.