Properties of the electron-positron plasma created from a vacuum in a strong laser field: Quasiparticle excitations

Abstract

Solutions of a kinetic equation are investigated which describe, on a nonperturbative basis, the vacuum creation of quasiparticle electron-positron pairs due to a strong laser field. The dependence of the quasiparticle electron (positron) distribution function and the particle number density is explored in a wide range of the laser radiation parameters, i.e., the wavelength $\ensuremath{\lambda}$ and amplitude of electric field strength ${E}_{0}$. Three domains are found: the domain of vacuum polarization effects where the density of the ${e}^{\ensuremath{-}}{e}^{+}$ pairs is small (the ``calm valley'') and two accumulation domains in which the production rate of the ${e}^{\ensuremath{-}}{e}^{+}$ pairs is strongly increased and the ${e}^{\ensuremath{-}}{e}^{+}$ pair density can reach a significant value (the short wavelength domain and the strong field one). In particular, the obtained results point to a complicated short-distance electromagnetic structure of the physical vacuum in the domain of short wavelengths $\ensuremath{\lambda}\ensuremath{\lesssim}{\ensuremath{\lambda}}_{\mathrm{acc}}=\ensuremath{\pi}/m$. For moderately strong fields ${E}_{0}\ensuremath{\lesssim}{E}_{c}={m}^{2}/e$, the accumulation regime can be realized where a plasma with a high density of ${e}^{\ensuremath{-}}{e}^{+}$ quasiparticles can be achieved. In this domain of the field strengths and in the whole investigated range of wavelengths, an observation of the dynamical Schwinger effect can be facilitated.