Production of ultrahigh-current-density ion beams by short-pulse skin-layer laser–plasma interaction

Abstract
We report experimental evidence, supported by a simple theory and numerical calculations, that the skin-layer subrelativistic interaction of a short ( ⩽ 1 ps ) low-energy ( < 1 J ) 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 ( ⩾ 10 10 A ∕ cm 2 close to the target), comparable to those predicted for ballistically focused ion beams from relativistic laser–plasma interactions.