Acceleration of carbon ions in a skin-layer interaction regime in laser ablation experiments

The regime of skin-effect interaction was proposed as the mechanism of ion acceleration, and the range of validity of the skin-effect mode was established. The results are illustrated on laser evaporation of graphite with Nd:YAG laser (1.064 micrometers ), KrF laser (248 nm) and ArF laser (193 nm). The UV lasers the interaction has a bi-modal nature: the interaction may proceed initially in the skin effect regime resulting in a few high-energy ions, until the hydrodynamics expansion begins at the later stage. The skin- effect interaction at the initial stage of UV laser pulse gives the first, to our knowledge, explanation for acceleration of ions up to approximately 100 eV at the low laser intensities 108 - 109 W/cm2 and ns-range pulse duration.