General features of highly charged ion generation in laser-produced plasmas

The simple physical model of highly charged ion generation in plasma produced by laser irradiation with long pulse duration (>1 ns) and moderate intensities (<1015/λ2 W/cm2μm2) is presented. In the frame of a single theory, most of the experimental results on plasma diagnostics are described in total. It is shown that plasma temperatures, ion charge states, and ion velocities as well as angular distributions of highly charged ions can be explained with good accuracy by collisional absorption of laser energy, hydrodynamic acceleration of forming plasma, and three-body recombination through highly excited levels during plasma expansion into vacuum. The general scalings for plasma parameters are derived on the basis of the model proposed. (author)