Experimental and numerical study of the ionization dynamics of a nanosecond laser-produced aluminium plasma with picosecond resolution

An experimental and numerical analysis of the ionization dynamics of a freely expanding nanosecond laser-produced plasma is given. Point-projection X-ray absorption spectroscopy with picosecond time-resolution is used to provide a spatio-temporal mapping of the ion distribution. The average ionization state, calculated as a function of time and distance to the target, is used to benchmark hydrodynamics and atomic physics codes. A comparison with several codes has been performed, showing that a full description of radiation transport, 2-D effects and detailed, time-dependent, atomic physics is necessary in order to explain the experimental results.