Effective ion acceleration of picosecond-duration well-collimated
bunches in the strong relativistic interaction of a short laser pulse
with a thin solid target has been experimentally demonstrated. In this
work, with reference to the sharp rear solid–vacuum interface,
where ion energization takes place, the one-dimensional
Poisson–Boltzmann equation is analytically solved on a finite
spatial interval whose extension is determined by requiring electron
energy conservation, resulting in the consistent spatial distributions
of the hot electrons created by the laser and of the corresponding
electrostatic potential. Then, the equation of motions for an ensemble
of test ions, initially distributed in a thin layer of the rear target
surface, with different initial conditions, is solved and the energy
spectrum corresponding to a given initial ion distribution is
determined.