Generation of Electron-Positron Pairs upon Grazing Incidence of a Laser Pulse on a Foil

The generation of electron-positron pairs from the interaction of laser radiation with a flat overcritical target (foil) is studied. The parameters of the generated pairs such as their number, density, spectrum and angular distribution are determined using full-scale three-dimensional particle-in-cell simulation taking into account quantum-electrodynamic (QED) effects. Two interaction configurations are investigated based on focusing six laser pulses onto a solid target with parameters expected at the XCELS laser facility. The configurations are not optimum in terms of the parameters ultimately achievable at this facility but they are reliable and quite simple in terms of practical feasibility. It is shown that even in these configurations it is possible to generate electron-positron pairs with energies up to GeV units, the total number of pairs exceeding 10(11), and with an average density of 2 x 10(20) cm(-3). Generating electron-positron plasma with such parameters opens up opportunities for laboratory investigation of some astrophysical phenomena.