Measurements of Ablation Pressure and Mass Ablation Rate Using a Target Pendulum and a Thin Foil Target at 10 µm Laser Wavelength

The ablation pressure and the mass ablation rate for a 10 µm CO2 laser were measured using two methods: a ballistic target pendulum and shifted X-ray emission images which are equivalent to X-ray back-lighting. The measured ablation pressure was 10 Mbar and the mass ablation rate was 106 g/cm2·sec at the absorbed laser intensity of 5×1013 W/cm2. Comparing the ablation mass rate measured by the pendulum with that derived from the penetration depth of the hot electrons using Kα line emission, we could identify the hot electron driven ablation as the dominant process.