A High Precision Numerical Simulation Method of Laser Ablation Based on Optimal Weight Factor

Abstract

The invention discloses a laser ablation high-precision numerical simulation method based on an optimal weight factor, which is suitable for the technical field of numerical simulation of the interaction between laser and matter. This method aims to use the finite difference method to numerically solve the partial differential equation of heat conduction, so as to simulate the evolution of the temperature field distribution of the target material under the action of laser ablation. In the finite difference weighted implicit scheme, the commonly used weight factors are 0, 1 or 0.5, while this method combines linear fitting iteration and nonlinear fitting methods according to the specific equation parameters and discrete space-time grid parameters in the current problem to search for optimal weight factor values ​​specific to the problem at hand. The method of searching for the optimal weight factor in the present invention is simple, efficient, and highly accurate, and the accuracy of the numerical calculation result can be significantly higher than that based on the commonly used weight factor to solve the partial differential equation based on the optimal weight factor obtained by searching. The invention is suitable for numerical simulation of laser pulse ablation solid target.

Description

technical field [0001] The invention relates to the technical field of numerical simulation of the interaction between laser and matter, specifically a high-precision numerical simulation method for laser ablation based on optimal weight factors. The main feature of this method is that the accuracy of calculation results can be significantly higher Based on results based on commonly used weighting factors. Background technique [0002] Laser-Matter Interaction (Laser-Matter Interaction) can bring various physical, chemical, biological and other effects, so it has a wide range of applications, such as: material processing (surface heat treatment, cutting and welding, etc.), material preparation (deposited film, Micro-nano materials, etc.), spectroscopic analysis (laser-induced breakdown spectroscopy, laser absorption spectroscopy, etc.), biomedicine (diagnosis, surgery), etc. Laser ablation is one of the most common physical effects of the interaction between laser and solid...

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Problems solved by technology

[0005] 1. For the forward Euler scheme: the accuracy is not high enough; the result is not unconditionally stable, but the grid parameters must meet certain conditions.

[0006] 2. For the backward Euler format: Although the result is unconditionally stable, the accuracy is low, usually not as good as the forward Euler format

[0007] 3. For the Crank-Nicolson scheme: Although the result is unconditionally stable, the accuracy is usually higher than that of the forward Euler scheme and the backward Euler scheme, but like the first two schemes, the weight factor is also a fixed value, which lacks the basis for specific problems and The specific grid parameters are targeted, so for most problems, there is still a large gap between the accuracy and the ideal level

[0008] 4. For the weighted implicit scheme based on the optimal weight factor discussed in the above literature: these literatures actually only pointed out the existence of the optimal weight factor value in theory through simple examples, but did not give how to apply it in practical problems In addition, the examples cited in the literature are relatively simple, and are limited to the case where there is no external source term. In the process of laser ablation, the laser pulse continuously heats the target material, and the heat conduction equation has an external heat source term. more complicated than that described in the literature

Therefore, the content discussed in the above existing literature cannot meet the application requirements of solving the actual laser ablation heat conduction equation

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