Nonlinear Behavior of Electromagnetic Waves in Ultra‐Relativistic Electron‐Positron Plasmas

Abstract

A set of nonlinear equations which can self-consistently describe the behavior of high frequency Electromagnetic (EM) waves in un-magnetized, ultra-relativistic electron-positron (e-p) plasmas is obtained on the basis of Vlasov-Maxwell equations. Nonlinear wave-wave, wave-particle interactions lead to the coupling of high frequency EM waves with low frequency density perturbations which result from EM waves radiation pressure. The same as that in conventional electron-ion (e-i) plasmas, strong EM waves in e-p plasmas will give rise to density depletion in which itself are trapped. But on the contrary to that in e-i plasmas, there no longer exists electrostatic acoustic-like wave in e-p plasmas due to the absence of mass difference. For linear polarized EM waves, a stationary EM soliton with a spiky structure will be formed. The possible relation of the localized field to pulsar radio pulse is discussed.

Magnetic field induced by strong transverse plasmons in ultra-relativistic electron-positron plasmas

“…This theory had been generalized to the generation of magnetic field in plasmas containing ultrarelativistic electrons and non-relativistic ions (Li et al 2008), and used to investigate the nonlinear behavior of transverse plasmons in isothermal ultra-relativistic EP plasmas (Liu & Liu 2011). If similar physical processes are taken into account, there are some similarities between the paper and those mentioned above.…”

“…The prompt γ-rays in the GRBs are assumed to be produced by internal shock that may be dominated by the ultrarelativistic electron-positron pairs (Medvedev et al 2005). In our previous paper we have come to the conclusion that the interaction of transverse plasmons with isothermal ultra-relativistic EP plasma will not excite magnetic field (Liu & Liu 2011). The reason is that the same mass and the opposite charge of EP pairs leads to the cancellation of magnetic currents, while one can expect that the spontaneous magnetic field maybe present for nonisothermal ultra-relativistic EP plasma, i.e., T e T p .…”

Elliptically polarized electromagnetic waves in a magnetized quantum electron-positron plasma with effects of exchange-correlation

“…(18) and (19) into Eqs. (16) and (17), we obtain for nonzero values of E x and E y the following dispersion relations for the quantum modified X-wave and the upperhybrid wave…”

“…(20), the factor 2 appears due to pair plasmas with equal mass and unperturbed number density. Also, after substitutions of the solutions (18) and (19) into Eqs. (16) and (17), we note that (because of pair plasmas) the corresponding terms ∝ E y and E x in these equations cancel each other.…”

“…Several authors have investigated the propagation characteristics of EM waves in EP plasmas (see, e.g., Refs. [14][15][16][17][18]. It is well known that the quantum effects can play a vital role in plasmas a) Electronic mail: mshmansouri@gmail.com b) Electronic mail: apmisra@visva-bharati.ac.in; apmisra@gmail.com when the de Broglie wavelength becomes comparable to the average inter-particle distance 19 .…”