scholarly journals Hemispherical shock wave decay in laser-matter interaction

1993 ◽  
Vol 11 (1) ◽  
pp. 221-225 ◽  
Author(s):  
Irith Gilath ◽  
Shalom Eliezer ◽  
Shalom Eliezer ◽  
Tuvia Bar
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Linear Relationship ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Target Thickness ◽  
High Irradiance ◽  
Wave Decay ◽  
Matter Interaction ◽  
Ablation Pressure

A high-irradiance short pulsed laser was used to generate hemispherical shock waves in planar targets. A linear relationship was obtained between the laser energy for threshold spall conditions (EL) and the cubic target thickness (d): EL = 45.3d3 + 4.9, where EL is in J and d is in mm. It is found that the laser-induced ablation pressure decays with the distance to a power slightly greater than 2.

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.

Shock wave decay and spall strength in laser‐matter interaction

1990 ◽  
Vol 68 (1) ◽  
pp. 356-358 ◽  
Author(s):  
S. Eliezer ◽  
Y. Gazit ◽  
I. Gilath
Keyword(s):  
Shock Wave ◽  
Spall Strength ◽  
Wave Decay ◽  
Matter Interaction

Discussion on plasma shock waves generated by high-power pulsed laser

2003 ◽  
Vol 793 ◽  
Author(s):  
ZhiHua Li ◽  
DuanMing Zhang ◽  
Li Guan
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Pulsed Laser ◽  
Point Explosion ◽  
Propagation Characteristics ◽  
The Difference ◽  
Plasma Shock Wave ◽  
First Time ◽  
Plasma Shock ◽  
The Ideal

ABSTRACTSedov-Taylor theory is modified to describe plasma shock waves generated in a pulsed laser ablating process. Under the reasonable asymptotic behavior and boundary conditions, the propagating rules in the global free space (including close areas and mid-far areas) of pulsed-laser-induced shock waves are established for the first time. In particular, the temporal behavior of energy causing the difference of the propagation characteristics between the practical plasma shock wave and the ideal shock wave in point explosion model is discussed in detail.

Global-Space Propagating Characteristics of Pulsed-Laser-Induced Shock Waves

2003 ◽  
Vol 17 (19) ◽  
pp. 1057-1066 ◽  
Author(s):  
Zhihua Li ◽  
Duanming Zhang ◽  
Boming Yu ◽  
Li Guan
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Pulsed Laser ◽  
Wave Theory ◽  
Point Explosion ◽  
Theoretical Predictions ◽  
Shock Wave Theory ◽  
Plasma Shock Wave ◽  
Relationship Of ◽  
Plasma Shock

Under the propagating limitation-conditions and based on the pulsed-laser-induced plasma shock wave theory,1 the propagating rules in the global free space (including close areas and mid-far areas) of pulsed-laser-induced shock waves are established for the first time. Compared with the previous work by Bian et al.,2 our theoretical model can directly lead to the relationship of the initial Mach number M0 of plasma shock waves and the whole energy E released into plasma shock waves from a pulsed laser without any approximations or any unnecessary experimental parameters. Here, M0 is also related to the pulse duration τ0 and the sound velocity υ0 in the atmosphere; the variation of attenuation index τ, as a function of laser parameters (especial τ0), is also obtained, and our theoretical predictions of mid-far propagating rules of plasma shock waves are in good agreement with experimental results. In addition, it should be noted that Sedov–Taylor solutions to the ideal shock wave in a point explosion are only the approximations of the propagating rules in the mid-far area of pulsed-laser plasma shock waves that we obtained.

scholarly journals Experimental Study on Interaction between Nanosecond Pulsed Laser and Normal Shock Wave

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jilin Shi ◽  
Diankai Wang ◽  
Longcheng Huang
Keyword(s):  
Shock Wave ◽  
High Temperature ◽  
Drag Reduction ◽  
Laser Plasma ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Normal Shock ◽  
Low Density ◽  
Density Region ◽  
Normal Shock Wave

Nanosecond pulsed lasers possess two remarkable advantages: a high peak power density and the ability to break down air to form plasma readily. Therefore, they have significant practical value in the drag reduction of a supersonic body. An experimental investigation is conducted on the fundamental physical phenomenon of the interaction of the pulsed laser plasma with a normal shock wave to reveal the mechanism of drag reduction. Moreover, a high-precision schlieren system is developed to measure complex wave structures with a time resolution of up to 30 ns and a spatial resolution up to 1 mm. A high-speed particle image velocimetry system is set up to measure the velocity and vorticity of the flow field quantitatively; the system has a time resolution of up to 500 ns. The characteristics of the spherical shock wave and the high-temperature and low-density region induced by the laser plasma are presented. The flow characteristics and evolution process of the laser plasma under a normal shock wave are substantially revealed. The cause of the supersonic drag reduction by the pulsed laser plasma is illustrated with numerical simulation results. The following results are obtained in this study: the initial Mach number of the shock wave induced by the laser plasma increases with the laser energy, and the shape of the wave gradually evolves from a droplet shape to a spherical shape. The propagation velocity decreases with time and is close to the sound velocity after 50 μs. The shape of the initial high-temperature and low-density region is approximately spherical; it subsequently destabilizes to form a sharp spike structure in the laser’s incident direction. Ultimately, the region evolves into a double-vortex ring structure with upper and lower symmetry; the size of this region increases with the laser energy.

scholarly journals Physics and applications with laser-induced relativistic shock waves

2016 ◽  
Vol 4 ◽  
Author(s):  
S. Eliezer ◽  
J. M. Martinez-Val ◽  
Z. Henis ◽  
N. Nissim ◽  
S. V. Pinhasi ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Detonation Wave ◽  
Bulk Material ◽  
High Irradiance ◽  
Alpha Particles ◽  
Relativistic Shock ◽  
Laser Acceleration ◽  
The Creation ◽  
Special Case

The laser-induced relativistic shock waves are described. The shock waves can be created directly by a high irradiance laser or indirectly by a laser acceleration of a foil that collides with a second static foil. A special case of interest is the creation of laser-induced fusion where the created alpha particles create a detonation wave. A novel application is suggested with the shock wave or the detonation wave to ignite a pre-compressed target. In particular, the deuterium–tritium fusion is considered. It is suggested that the collision of two laser accelerated foils might serve as a novel relativistic accelerator for bulk material collisions.

Numerical Analysis of Behavior on Opposing Unsteady Supersonic Jets in a Flow Field with Shields

2018 ◽  
Vol 910 ◽  
pp. 96-101 ◽  
Author(s):  
Toshiki Kinoshita ◽  
Hiroshi Fukuoka ◽  
Ikurou Umezu
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Pulsed Laser ◽  
Supersonic Jets ◽  
Collision Dynamics ◽  
Ansys Fluent ◽  
And Shock Waves ◽  
Pass Through ◽  
Background Gas ◽  
Volume Method

Collision dynamics of opposing unsteady supersonic jets injected in background gas with shock waves were calculated to simulate double pulsed laser ablation. Since the jets are deflected by collision and the motion of debris is ballistic. This characteristic can be used to reduce the number of debris when shields are mounted in front of substrate. The flow of jets through installed shields is complicated by the interaction between shields and jets, and between shields and shock waves. We investigate influence of shield position on the shock waves and the jets by numerical calculations. Axisymmetric two-dimensional compressible Euler equations were solved using the finite volume method by using ANSYS Fluent 14.0.0 code. The shields with slit was mounted parallel to the direction of initially injected jets. In order to investigate the influence of shield position on the shock waves and the jets, the shield position and background gas pressure were adopted as parameters. The jets and shock wave are deflected by collision and they can pass through the slit of shields. The passed shock wave reflects at the substrate mounted behind the slits and it forces back the jet to decrease the jet velocity. The shield position governs the velocity and amount of the jet that reach the substrate.

scholarly journals Hydrodynamic evolution of laser driven diverging shock waves

1990 ◽  
Vol 8 (1-2) ◽  
pp. 247-252 ◽  
Author(s):  
M. A. Harith ◽  
V. Palleschi ◽  
A. Salvetti ◽  
D. P. Singh ◽  
G. Tropiano ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Temporal Evolution ◽  
Laser Energy ◽  
Appreciable Effect ◽  
Density Jump ◽  
Hydrodynamic Evolution ◽  
Self Similar Solution ◽  
Glass Cell ◽  
Strong Explosion

Spherically symmetric shock waves have been produced via Nd3+ laser induced break-down in helium, nitrogen and air at pressures ranging from 760 Torr to 2300 Torr. The measurements are performed at different absorbed laser energies (E0 = 0.05 J to 2 J) at the center of the experimental spherical glass cell where the breakdown of the gas takes place. The temporal evolution of the shock wave followed by a double-pulse, doublewavelength holographic technique is described hydrodynamically well by the point strong explosion theory. The ambient gas counterpressure plays a negligible role in determining the shock wave motion even at low laser energy absorption (E0 ≤, 0.5 J), whereas it has an appreciable effect on the gas density jump at the shock wave itself. The experimental data on temporal evolution of the density jump of the gas and the corresponding theoretical profiles obtained adopting a non-self-similar solution at the same laser absorbed energy are found to be in good mutual agreement.

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