Optimization of flat-cone targets for enhanced laser-acceleration of protons

Abstract We have analyzed the acceleration of laser-generated protons, produced at the rear surface of flat-cone targets irradiated by an ultra-intense ( I ∼5×10 19  W/cm 2 ) short (400 fs) laser pulse. We used different target sizes and shapes in order to find the optimum target layout. We find that for targets with a too narrow cone structure, the production of the hot electrons, driving the proton acceleration, is located prior to the accelerating rear surface of the target, resulting in a reduced maximum proton energy.