Efficiency of ablative loading of material upon the fast-electron transfer of absorbed laser energy

We present the results of experiments on the short-term irradiation of a solid material by a laser beam. The data testify to a rise in efficiency of the energy transfer from the laser pulse to a shock wave due to the fast-electron energy transfer. The experiments were performed with massive aluminium targets on the PALS iodine laser, whose pulse duration (0.4 ns) was much shorter than the time of shock decay and crater formation in the target (50–200 ns). The irradiation experiments were carried out using the fundamental laser harmonic (1.315 μm) with an energy of 360 J. The greater part of the experiments were performed for the radiation intensity exceeding 10¹⁵ W cm^-2, which corresponded to the efficient generation of fast electrons under the conditions where the relatively long-wavelength iodine-laser radiation was employed. The irradiation intensity was varied by varying the laser beam radius for a specified pulse energy.