Phase space modulation of laser produced protons with a double-foil target generation of quasimonoenergetic proton beams

Abstract

It is shown by one-dimensional particle-in-cell simulation that quasimonoenergetic protons can be generated from a double-solid-foil target irradiated by two ultrashort intense laser pulses. In this approach, one uses the first laser pulse irradiating on the first foil to generate the energetic protons, and one uses the second laser pulse irradiating on the second foil to generate an electrostatic field, which modulates the energy spectrum of protons from the first foil. Quasimonoenergetic protons with tunable energy peaks can be obtained by controlling the time delay and intensity of the second pulse as well as the distance between the two foils. It is also found that a preplasma on the second foil increases the peak energy. The dependence of the proton beam quality on the laser and target parameters is also discussed.