The possibilities of producing ultrahigh-current-density ps ion fluxes
by the skin-layer interaction of a short (≤ 1ps) laser pulse with
plasma were studied using two-fluid hydrodynamic simulations, and the
time-of-flight measurements. Backward-emitted ion fluxes from a massive
(Au) target as well as forward-emitted fluxes from various thin foil
targets irradiated by a 1-ps laser pulse of intensity up to 2 ×
1017 W/cm2 were recorded. Both the simulations
and the measurements confirmed that using the short-pulse skin-layer
interaction of a laser pulse with a thin pre-plasma layer in front of a
solid target, a high-density collimated ion flux of extremely high ion
current density (∼ 1010 A/cm2 close to the
target), can be generated at laser intensity only ∼ 1017
W/cm2. The ion current densities produced by this way were
found to be comparable to (or even higher than) those estimated from
recent short-pulse experiments using a target normal sheath acceleration
mechanism at relativistic laser intensities. The effect of the target
structure on the current densities and energies of forward-emitted ions is
demonstrated.