Laser-induced Coulomb mirror effect: Applications for proton acceleration

Using two-dimensional particle-in-cell simulations, the temporal evolution of the uncompensated charge on an ultra-thin (400 nm) foil target ionized by a relativistically intense laser pulse is studied in detail. The analysis reveals a new dynamic regime of acceleration of light ions/protons that allows particles to experience the maximum acceleration potential created by the laser. As an alternative to the conventional double-layer target, a new target geometry in which the proton energy is enhanced by ≈ 30% is proposed.