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

Abstract

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 K_α line emission, we could identify the hot electron driven ablation as the dominant process.