Laser-induced plasma shock wave and cavity on metal surface underwater

Abstract

The laser‐induced plasma shock waves and related cavitation bubbles on an aluminum surface underwater have been experimentally studied with a high‐sensitivity optical deflection system. The expansion of the shock wave pulse duration, the positions where shock waves attenuate to acoustic transients, the maximum bubble radii, and the bubble collapse center shifts have been determined experimentally. A high‐pressure wall behind the bubble has also been observed with this deflection system. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 25: 307–311, 2000.

Observation of microsphere clusters separated by pulsed laser in water environment

“…When the power density of laser focused in water exceeds the breakdown threshold of water, water is broken down to form plasma, which is consistent with Xu's research [21]. When the plasma is subjected to high-energy laser, the internal pressure rises sharply, resulting in highspeed shock waves, Chen's experiment can verify that [22]. Figure 2(b) shows the final separated positions of the microspheres due to the pulsed laser are depicted.…”

Defect measurement using the laser ultrasonic technique based on power spectral density analysis and wavelet packet energy

“…The work principle of LUT can be divided into two cases according to whether the power density of the laser pulse is close to the damage threshold. The first case is an ablation mechanism, 13,14 and the second is a thermoelastic effect. 15 A schematic diagram of LUT is shown in Figure 1.…”

A New Method for Detecting Jet Impact Force of Laser Cavity

“…After the method of laser cavity's appearance, laser is mainly used by researchers to study the dynamical features of cavity [1,4] . There are three main methods to study the impact force of high-velocity jet on the stationary face during the corruption period of the cavity: the first is to calculate the jet velocity by ultra-high speed camera, and then compute the impact force of the jet [4,10] , the second is to calculate the impact force from the depth of the erosion on the stationary face and the strength of material, the third way is to calculate the impact force using PVDF or PZT [3,4] . However, these three methods all have their own disadvantages.…”