Radiation-pressure-dominant acceleration: Polarization and radiation reaction effects and energy increase in three-dimensional simulations.

Polarization and radiation reaction (RR) effects in the interaction of a superintense laser pulse (I > 10^23 W/cm^2) with a thin plasma foil are investigated with three dimensional particle-in-cell (PIC) simulations. For a linearly polarized laser pulse, strong anisotropies such as the formation of two high-energy clumps in the plane perpendicular to the propagation direction and significant radiation reactions effects are observed. On the contrary, neither anisotropies nor significant radiation reaction effects are observed using circularly polarized laser pulses, for which the maximum ion energy exceeds the value obtained in simulations of lower dimensionality. The dynamical bending of the initially flat plasma foil leads to the self-formation of a quasi-parabolic shell that focuses the impinging laser pulse strongly increasing its energy and momentum densities.