Laser-assisted interaction between nonrelativistic electrons and positrons

Electromagnetic Solitons in Degenerate Relativistic Electron-Positron Plasma

The existence of soliton-like electromagnetic (EM) distributions in a fully degenerate electron-positron plasma is studied applying relativistic hydrodynamic and Maxwell equations. For circularly polarized wave it is found that the soliton solutions exist both in relativistic as well as nonrelativistic degenerate plasmas. Plasma density in the region of soliton pulse localization is reduced considerably. The possibility of plasma cavitation is also shown.

Tail-wave-assisted Positron Acceleration in Nonlinear Laser Plasma Wakefields

Relativistic laser wakefield acceleration is characterized by an unsurpassed accelerating gradient, which is very suitable for electron acceleration over short distances and could be a promising candidate for next-generation compact accelerators. However, using this technique for positron acceleration is still challenging because positively charged particles are naturally defocused in nonlinear wakefields. Here we propose and numerically demonstrate a scheme to accelerate an externally injected positron beam in a nonlinear laser wakefield in a regime where a tail wave is formed behind density …

在共振强电磁场辅助的 Breit-Wheeler 过程中产生超相对论正电子（电子）的窄束

Generation of narrow beams of ultrarelativistic positrons (electrons) in the resonant strong electromagnetic field-assisted Breit-Wheeler process

本文理论上研究了低于临界Schwinger场强下的共振外场辅助Breit-Wheeler过程，通过分析共振运动学与微分截面，预测了高能gamma量子产生超相对论正负电子窄束，其概率显著高于非共振过程。

Comparative study of the electron- and positron-atom bremsstrahlung

Fully relativistic treatment of the electron-atom and positron-atom bremsstrahlung is reported. The calculation is based on the partial-wave expansion of the Dirac scattering states in an external atomic field. A comparison of the electron and positron bremsstrahlung is presented for the single and double differential cross sections and the Stokes parameters of the emitted photon. It is demonstrated that the electron-positron symmetry of the bremsstrahlung spectra, which is nearly exact in the nonrelativistic regime, is to a large extent removed by the relativistic effects.

Short-wavelength soliton in ultrarelativistic electron-positron-ion plasmas

We derive a nonlinear equation governing dynamics of short-wavelength longitudinal waves in ultrarelativistic electron-positron-ion plasmas. In contrast to the recent work by Lashkin [Phys. Plasmas {\textbf{27}}, 102302 (2020)], where a similar equation was suggested in the framework of the Wigner function approach for a nonrelativistic electron-ion degenerate plasma, in our case which is based on the Vlasov kinetic equation all three species of particles (electrons, positrons and ions) should be present. The nonlinearity arises only in the presence of a population of ions. By numerical simula…

Disperson relation of finite amplitude Alfven wave in a relativistic electron- positron plasma

The linear dispersion relation of a finite amplitude, parallel, circularly polarized Alfvén wave in a relativistic electron-positron plasma is derived. In the nonrelativistic regime, the dispersion relation has two branches, one electromagnetic wave, with a low frequency cutoff at $\sqrt{1+2ω_p^2/Ω_p^2}$ (where $ω_p=(4πn e^2/m)^{1/2}$ is the electron/positron plasma frequency), and an Alfvén wave, with high frequency cutoff at the positron gyrofrequency $Ω_p$. There is only one forward propagating mode for a given frequency. However, due to relativistic effects, there is no low frequency cutof…