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

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 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(-)e(+) pairs is small (the "calm valley") and two accumulation domains in which the production rate of the e(-)e(+) pairs is strongly increased and the e(-)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 lambda less than or similar to lambda(acc) = pi/m. For moderately strong fields E-0 less than or similar to E-c = m(2)/e, the accumulation regime can be realized where a plasma with a high density of e(-)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.