采用自行研制的高灵敏度光束偏转测试系统,对脉冲激光烧蚀水下金属产生的等离子体冲击波和空泡效应进行了实验研究。实验得到了激光等离子体冲击波的传播规律、冲击波与激光空泡的分离过程、空泡的脉动特性以及空泡溃灭冲击波的形成机制。结果表明,空泡最大和最小泡径、振荡周期均随着脉动次数的增加呈减小趋势,且减小幅度较大。最小收缩泡径由泡能和腔内含气量共同决定。在同一次脉动过程中,空泡膨胀所需的时间明显大于收缩所需的时间。

Laser-induced plasma shock wave and cavitation bubble by pulsed laser ablation of a metal in water are investigated by a high-sensitive optical beam deflection technique. The experimental results present the laser-produced plasma shock waves propagation, the detachment of the shock wave from bubble wall, cavitation bubble oscillation and bubble-collapse-induced shock waves generation in the vicinity of a solid boundary. It is shown that with the increase of the number of oscillating cycles, the maximum and minimum bubble radii are decreased sharply, as well as the corresponding oscillating durations. The minimum bubble radius is determined by the bubble energy and gas-vapor content in a cavity. The duration of bubble expansion is obviously longer than that of contraction during the same oscillating cycle.