Temporal evolution of pressure profiles for laser-induced cavitation bubble on the metal surface

When a laser is focused on an underwater object, it experiences a large amount of pressure owing to the plasma confinement effect of water. A hemispherical bubble is generated on the surface of the object, and large pressure is generated when the bubble collapses. In this study, we conducted experiments using different laser energies to analyze the pressure-time histories associated with bubble contraction. The maximum pressure was 10%-40% of the laser ablation pressure, whereas the pressure pulse width was 5-10 times longer than the laser pulse width. Furthermore, the bubble motion could be adiabatically explained, except for the plasma interaction region. The results indicate that the pressure at which the bubble collapses does not depend on the maximum size of the generated bubble but depends on the energy of water vapor within the bubble.

Automated summary

When a laser is focused on an underwater object, the plasma confinement effect causes a large amount of pressure. This results in the formation of a hemispherical bubble on the object's surface, which generates high pressure when it collapses. Experimental analysis using different laser energies showed that the maximum pressure ranged from 10% to 40% of the laser ablation pressure, and the pressure pulse width was 5-10 times longer than the laser pulse width. The collapse pressure of the bubble depended on the energy of water vapor within the bubble, rather than the maximum bubble size.