We report experimental evidence, supported by a simple theory and numerical calculations, that the skin-layer subrelativistic interaction of a short (⩽1ps) low-energy (<1J) laser pulse with a thin preplasma layer in front of a solid target can produce a collimated fast ion flux of extremely high ion current density (⩾1010A∕cm2 close to the target), comparable to those predicted for ballistically focused ion beams from relativistic laser–plasma interactions.

The possibilities of producing ultrahigh-current-density ps ion fluxes by the skin-layer interaction of a short~Յ 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 ϫ 10 17 W0cm 2 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~; 10 10 A0cm 2 close to the target!, can be generated at laser intensity only ; 10 17 W0cm 2 . 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.

No abstract

Generation of high speed dense plasma blocks is well known from hydrodynamic theory and computations (PIC) with experimental confirmation by Badziaket al.(2005) since ps laser pulses with power above TW are available. These blocks may be used for fusion flame generation (thermonuclear propagation) in uncompressed solid state deuterium and tritium for very high gain uncomplicated operation in power stations. Hydrodynamic theory from computations from the end of 1970s to recent, genuine two fluid computations support the skin layer accelerations (SLA), by nonlinear (ponderomotive) forces as measured now in details under the uniquely selected conditions to suppress relativistic self-focusing by high contrast ratio and to keep plane geometry interaction. It is shown how the now available PW-ps laser pulses may provide the very extreme conditions for generating the fusion flames in solid state density DT.