Propagation of Shock Wave At the Cavitation Bubble Expansion Stage Induced by a Nanosecond Laser Pulse

2021 ◽  
Author(s):  
Siyuan Geng ◽  
Zhifeng Yao ◽  
Qiang Zhong ◽  
Yuxin Du ◽  
Ruofu Xiao ◽  
...  
Keyword(s):  
Shock Wave ◽  
Laser Pulse ◽  
Wave Front ◽  
Cavitation Bubble ◽  
Bubble Radius ◽  
Front Velocity ◽  
High Time ◽  
Nanosecond Laser ◽  
Time Resolved ◽  
Expansion Stage

Abstract The objective of this paper is to reveal the attenuation characteristics of a shock wave after optical breakdown in water, with laser pulses of 10-ns duration. A high time-resolved shadowgraph method is applied to capture the temporal evolutions of the cavitation bubble wall and shock wave. The experiments are carried out on a single bubble generated far away from the free surface and the rigid walls with laser pulse energies of 22 mJ, 45 mJ and 60 mJ. The results show that a high, time-resolved, wave front velocity of the shock wave is identified, and the maximum velocity can reach up to around 4000 m/s. An asymmetric shock wave is observed at the very start of the bubble expansion stage, and the process of the sharp attenuation of wave front velocity down to sound velocity, is accomplished within 310-ns. The possible relationship of the cavitation bubble and the shock wave is discussed and a prediction model, using the maximum bubble radius and the corresponding time calculated by the Gilmore model, is proposed to calculate the location of the wave front.

Early Dynamics of a Laser-induced Underwater Shock Wave

2021 ◽  
Author(s):  
Guihua Lai ◽  
Siyuan Geng ◽  
Hanwen Zheng ◽  
Zhifeng Yao ◽  
Qiang Zhong ◽  
...  
Keyword(s):  
Shock Wave ◽  
Numerical Method ◽  
Cavitation Bubble ◽  
Laser Energy ◽  
Optical Breakdown ◽  
Pulsed Laser ◽  
Underwater Shock Wave ◽  
Time Resolved ◽  
High Attenuation ◽  
Nanosecond Pulsed Laser

Abstract The objective of this paper is to observe and investigate the early evolution of the shock wave, induced by a nanosecond pulsed laser in still water. A numerical method is performed to calculate the propagation of the shock wave within 1µs, after optical breakdown, based on the Gilmore model and the Kirkwood-Bethe hypothesis. The input parameters of the numerical method include the laser pulse duration, the size of the plasma and the maximally extended cavitation bubble, which are measured utilizing a high time-resolved shadowgraph system. The calculation results are verified by shock wave observation experiments at the cavitation bubble expansion stage. The relative errors of the radiuses and the velocity of the shock wave front, reach the maximum value of 45% at 5 ns after breakdown and decrease to less than 20% within 20 ns. The high attenuation characteristics of the shock wave after the optical breakdown, are predicted by the numerical method. The quick time and space evolution of the shock wave are carefully analyzed. The normalized shock wave width is found to be independent of the laser energy and duration, and the energy partitions ratio is around 2.0 using the nanosecond pulsed laser.

Time-resolved current response of a nanosecond laser pulse illuminated STM tip

1999 ◽  
Vol 68 (6) ◽  
pp. 637-641 ◽  
Author(s):  
J. Jersch ◽  
F. Demming ◽  
I. Fedotov ◽  
K. Dickmann
Keyword(s):  
Laser Pulse ◽  
Nanosecond Laser Pulse ◽  
Nanosecond Laser ◽  
Current Response ◽  
Time Resolved

Time-resolved digital holographic diagnosis of the shock wave in water induced by femtosecond laser pulse

Optik ◽  
2016 ◽  
Vol 127 (4) ◽  
pp. 2017-2020
Author(s):  
Xiaolei Wang ◽  
Pan Wang ◽  
Lipei Song ◽  
Sixing Xi
Keyword(s):  
Shock Wave ◽  
Laser Pulse ◽  
Femtosecond Laser ◽  
Femtosecond Laser Pulse ◽  
Time Resolved

Modeling of Pressure Evolution During Nanosecond Laser Ablation of Metal Films

2009 ◽  
Author(s):  
Mohammad Hendijanifard ◽  
David A. Willis
Keyword(s):  
Shock Wave ◽  
Laser Ablation ◽  
Pulse Width ◽  
Metal Films ◽  
Normal Shock ◽  
Nanosecond Laser ◽  
Time Resolved ◽  
Aluminum Films ◽  
Nanosecond Laser Ablation ◽  
Fluid Properties

Nanosecond laser ablation is studied using a theoretical model combined with experimental data from laser ablation of metal films. The purpose of the research is to obtain the recoil pressure boundary condition resulting from explosive phase change. The ablation experiments are performed using a Nd:YAG laser of 1064 nm wavelength and 7 ns pulse width at full width half maximum. Three samples, 200 and 1000 nm aluminum films and 1000 nm nickel films, are used in the experiments. The transient shock wave positions are obtained by a time-resolved shadowgraph technique. A N2-laser pumped dye laser with 3 ns pulse width is used as an illumination source and is synchronized with the ablation laser to obtain the transient shock wave position with nanosecond resolution. The transient shock position is used in a model for finding the shock wave speed as well as the pressure, temperature, and velocity just behind the shock wave. A power law is used for fitting curves on the experimentally obtained shock wave position. Knowing the shock wave position, the normal shock equations are used to calculate the thermo-fluid properties behind the shock wave. The solutions are compared with the Taylor-Sedov solution for spherical shocks and the reason for the deviation is described. The thermo-fluid property results show similar trends for all tested samples. The results show that the Taylor-Sedov solution under-estimates the pressure behind the shock wave when compared to the normal shock results.

scholarly journals Time-resolved measurements of the response of a STM tip upon illumination with a nanosecond laser pulse

1998 ◽  
Vol 66 (6) ◽  
pp. 615-619 ◽  
Author(s):  
J. Boneberg ◽  
M. Tresp ◽  
M. Ochmann ◽  
H.-J. Münzer ◽  
P. Leiderer
Keyword(s):  
Laser Pulse ◽  
Nanosecond Laser Pulse ◽  
Nanosecond Laser ◽  
Time Resolved ◽  
Time Resolved Measurements
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