Acceleration of laser-driven ion bunch from double-layer thin foils

Generation of monoenergetic ion bunch from a double-layer thin-foil target irradiated by an intenselinearly polarized laser pulse is investigated using two-dimensional particle-in-cell simulation. Theprotons in the front low-density hydrogen target layer accelerated by the space-charge field of thelaser-driven hot electrons can penetrate through the high-Z high-mass and high-density ion layer,resulting in an energetic proton bunch. A part of the latter is further accelerated by the space-chargefield of the hot electrons in the vacuum behind the high-Z ion layer. With this scheme, quasimonoenergeticproton bunches can be produced using presently available laser pulses of moderatecontrast and duratio