Effect Of Bubbles And Microstructure On Laser Damage Threshold Of Fused Silica And Absorbing Glass

How to increase the laser damage threshold of the amorphous SiO₂ optical element in the inertial confinement fusion device has become a key issue that limits the increase in energy density in ICF?Inertial Confinement Fusion?.Fused silica and absorbing glass are the most commonly used amorphous SiO₂ optical elements in inertial confinement fusion devices.With the continuous increase of laser energy density,the bubbles and surface microstructures have become important factors that cannot be ignored for lowering the laser damage threshold of optical elements.After the optical element is damaged,it not only reduces the quality of the light and improves the load,but also the secondary damage caused by the damaged particles attached to the device,which seriously reduces the life of the inertial system and limits the development of ICF technology.Therefore,it is of great practical significance to study the influence of bubbles and microstructures in fused silica and absorption glass on the laser damage threshold.In this paper,the influence of bubbles and microstructures in fused silica and absorption glass on the laser damage threshold is studied,and the mechanical properties and motion analysis of bubbles in fused silica in molten fluid are investigated;for the coupling of multiple bubbles in fused silica and absorption glass Problem,establish a double-bubble coupling model,and analyze the influence of double-bubble coupling parameters on the laser damage threshold;for the coupling of bubbles and microstructures in fused silica and absorbing glass,the coupling and coupling of bubbles and rectangular and sawtooth microstructures are studied The influence of parameters on the laser damage threshold;in the experiment,the change law of the number of damaged particles with double bubble coupling,bubble and microstructure coupling with the laser energy density was analyzed,and the corresponding simulation rule was verified.The main tasks as follows:First,the mechanical properties of bubbles in fused silica fluid are calculated,and the rising bubble model is established.The two-phase flow and level set method based on the incompressible Navier-Stokes equations are used to simulate the topological transient process of the fluid interface.The pressure distribution,velocity distribution,and initial shape change law around the bubble during the transient process are analyzed,and then the movement state of the bubble in the high-viscosity fused silica melt is understood.Then for the effect of double bubble coupling in fused silica and absorption glass on the laser damage threshold,a double bubble coupling model based on Mie scattering theory was established,and the effect of double bubble coupling parameters on the maximum light intensity of fused silica was studied.The influence of double bubble coupling parameters in the absorption glass on the laser damage threshold is analyzed with the angle of the stress field.Secondly,the influence of the bubble and microstructure coupling on the laser damage threshold in fused silica and absorbing glass is analyzed.The bubble and rectangular and sawtooth microstructure coupling models are established respectively.The coupling position parameter of the bubble and rectangular and sawtooth microstructure is the largest for fused silica.The law of light intensity is analyzed theoretically from the temperature field and the stress field.The effect of the coupling position parameter of the absorption bubble and the rectangular and sawtooth microstructure on the maximum temperature and maximum stress is analyzed,and then the law of the laser damage threshold is summarized.Finally,a laser shooting experiment was conducted to study the damage of double bubble coupling and bubble and microstructure coupling in fused silica.The damage morphology of the target point was compared,and the change law of the number of damaged particles with the laser energy density was summarized and analyzed.The laser damage threshold was obtained and verified.The corresponding simulation conclusion.