Generation of wakefields and electromagnetic solitons in relativistic degenerate plasmas

Abstract

The nonlinear interaction of intense linearly polarized electromagnetic waves (EMWs) with longitudinal electron density perturbations is revisited in relativistic degenerate plasmas. The nonlinear dynamics of the EMWs and the longitudinal field, driven by the EMW ponderomotive force, is governed by a coupled set of nonlinear partial differential equations. A numerical simulation of these coupled equations reveals that the generation of wakefields is possible in weakly relativistic degenerate plasmas with R0 ≡ pF /mc ≪ 1 and vg/c ∼ 1, where pF is the Fermi momentum, m is the mass of electrons, c is the speed of light in vacuum, and vg is the EMW group velocity. However, when the ratio vg/c is reduced to ∼ 0.1, the wakefield generation is suppressed, instead the longitudinal fields get localized to form soliton-like structures. On the other hand, in the regimes of moderate (R0 1) or strong relativistic degeneracy (R0 > 1) with vg/c ∼ 0.1, only the EM solitons can be formed.

Stability and evolution of electromagnetic solitons in relativistic degenerate laser plasmas

“…1997; Roy et al. 2020; Misra & Chatterjee 2018): where , and , (with its equilibrium value in laboratory frame), and are, respectively, the charge, the number density, the mass and -component of the velocity of electrons. Since ions form the neutralizing background, and so, , the equilibrium number density of electrons and ions.…”

“…The nonlinear interaction of linearly polarized finite amplitude intense laser pulse with longitudinal electron density perturbations that are driven by the laser ponderomotive force in a relativistic degenerate plasma can be described by the following set of dimensionless equations which are, the EM wave equation, the electron continuity and momentum equations and the Poisson equation in the Coulomb gauge (Gratton et al 1997;Roy et al 2020;Misra & Chatterjee 2018): ∂ 2 φ ∂z 2 = 4πe(γ e n e − n 0 ), (2.4) where d/dt ≡ ∂/∂t + v j • ∇, and e, n e (with its equilibrium value n 0 in laboratory frame), m e and v ez are, respectively, the charge, the number density, the mass and z-component of the velocity of electrons. Since ions form the neutralizing background, γ i = 1 and so, γ i n i = n 0 , the equilibrium number density of electrons and ions.…”

“…Furthermore, the dynamics of EM solitons in relativistic plasmas in an idealized case of circular polarization have been extensively studied within the framework of one-dimensional relativistic fluid model and particle-in-cell (known as PIC) simulations (Lehmann, Laedke & Spatschek 2006;Sundar et al 2011;Mikaberidze & Berezhiani 2015;Berezhiani, Shatashvili & Tsintsadze 2015). The theory has been revisited in the context of linearly polarized EM waves as well (Mancic, Hadzievski & Skoric 2006;Hadzievski et al 2002;Roy, Chatterjee & Misra 2020). Recently, the formation of standing EM solitons for circularly polarized EM waves in degenerate relativistic plasmas have been studied by Mikaberidze & Berezhiani (2015).…”

“…The theory has been revisited in the context of linearly polarized EM waves as well (Mancic, Hadzievski & Skoric 2006; Hadzievski et al. 2002; Roy, Chatterjee & Misra 2020). Recently, the formation of standing EM solitons for circularly polarized EM waves in degenerate relativistic plasmas have been studied by Mikaberidze & Berezhiani (2015).…”

Stability and evolution of electromagnetic solitons in relativistic degenerate laser plasmas

“…Furthermore, the dynamics of EM solitons in relativistic plasmas in an idealized case of circular polarization has been extensively studied within the framework of one-dimensional relativistic fluid model and particle-in-cell (PIC) simulations [9][10][11][12]. The theory has been revisited in the context of linearly polarized EM waves as well [13][14][15]. Recently, the formation of standing EM solitons for circularly polarized EM waves in degenerate relativistic plasmas has been studied by Mikaberidze et al [11].…”