Optimal acceleration of ions by laser pulses with a sharp leading edge

Abstract

We consider acceleration of ions through the interaction of a laser pulse with a sharp leading edge with nanofilms. At sufficiently large amplitude of the pulse, all the electrons can be expelled from the film, which provides an effective regime of ion acceleration. Limiting the maximum energy of ions can result from the longitudinal reverse motion of electrons to the initial position and by the transverse motion of electrons along the nanofilm surface, which causes the ion charge compensation. The characteristic parameters of the dynamics of ions and electrons in the system are analytically evaluated, which agree well with the results of two-dimensional numerical simulations by the particle-in-cell method. Optimisation of the acceleration process by using the analytical estimates makes it possible to select the optimal parameters of the laser pulse and nanofilm. Numerical simulation of ion acceleration at these parameters shows that the maximum energy of ions can be substantially increased.