“Light Sail” Acceleration Reexamined

The dynamics of the acceleration of ultrathin foil targets by the radiation pressure of superintense, circularly polarized laser pulses is investigated by analytical modeling and particle-in-cell simulations. By addressing self-induced transparency and charge separation effects, it is shown that for ``optimal'' values of the foil thickness only a thin layer at the rear side is accelerated by radiation pressure. The simple ``light sail'' model gives a good estimate of the energy per nucleon, but overestimates the conversion efficiency of laser energy into monoenergetic ions.