Analysis for mechanism of cavitation produced by CO₂ laser-generated ablation of the surface of water

Mechanism of surface cavitation produced by laser-generated ablation was analyzed. Photos of flow field was obtained by high-speed camera. It was found that development speed of cavitation was very high during the first 100 μs, and it would be in a relative equilibrium state in the next several hundreds microseconds. A simple model was used to calculate the balance shape of cavitation in different energy-flux density and its limitation was presented. Results of this study is valuable for discovering formation mechanics of thrust in the process of laser induced ablation of water and development of laser propulsion with liquid propellants.