Autofocused, enhanced proton acceleration from a nanometer-scale bulged foil

Abstract

We report an autofocused, enhanced proton acceleration by the interaction of an intense laser pulse with a bulged target. These results are obtained from two-dimensional particle-in-cell simulations using a real Gaussian laser pulse, normally incident on a bulged/planar, 60 nm thick foil (C:H=1:1). When the laser pulse hits the precurved target, energetic protons are converged on the axis automatically. For the bulged foil, due to oblique incidence at the wing region, the efficient vacuum heating at larger incidence angles will result in more energetic hot electrons than from the flat foil. The enhancement of hot electron temperature and density will result in a larger longitudinal field, which contributes to an enhancement of proton energy. The maximum proton energy of 124 MeV is attained from a bulged target irradiated by a linear polarized laser pulse at an intensity of 1.3×1020 W/cm2, which is two times higher than from the planar target (61 MeV).