Investigation of laser-induced bubble dynamics in water at high hydrostatic pressures

Hydrostatic pressure is a key factor that influences laser-induced bubble dynamics in water. In this work, we investigated laser-induced bubble dynamics at high hydrostatic pressures up to 53.2 MPa, by using a high-pressure chamber combined with the shadowgraph imaging technique. It was shown that at the atmosphere pressure, the bubble evolution agrees well with the Keller-Miksis model during the free expansion and collapse phase. As the ambient pressure increases, both the size and the oscillation period of the bubble decreases dramatically as a consequence of faster dynamics. The maximum bubble radius, as well as the collapse time, decrease nonlinearly with the increasing pressure; while the pressurization effect on bubble expansion before 100 ns is negligible due to the high internal bubble pressure in the early stage. Time-resolved plasma emission images were also taken with an ICCD camera to illustrate the plasma evolution at high hydrostatic pressures. It was demonstrated that at a high pressure above 40MPa, the plasma can gain energy from the bubble collapse, while the bubble will lose its energy, which may lead to a shorter collapse time than that obtained from the numerical calculation. This work provides insight into laser-induced bubble dynamics and the plasma-bubble interaction at high hydrostatic pressures. (C) 2021 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

Automated summary

Hydrostatic pressure plays a critical role in laser-induced bubble dynamics in water. Higher ambient pressure leads to reduced bubble size and oscillation period, as well as nonlinear decrease in maximum bubble radius and collapse time. At high pressures, plasma can gain energy from bubble collapse, while the bubble loses energy.