激光烧蚀冲量耦合系数解析计算模型

Analytical model for calculating laser ablation impulse coupling coefficient

利用激光清除空间碎片被认为是一种可行手段,冲量耦合系数是数值计算空间碎片清除效果的重要参数。建立了激光烧蚀冲量耦合系数解析计算模型,引入电离度参数,将气化机制与等离子体机制两种机制下的冲量耦合系数解析计算模型联系起来,建立统一的耦合系数解析模型。以空间碎片常见材料Al为例,计算得到冲量耦合系数、电离度、激光功率密度三者之间的变化关系。随着激光功率密度的增加,气化机制逐渐向等离子体机制过渡,电离度增加,直至完全电离,冲量耦合系数先增加后减少,并且在等离子机制占主导情况下达到最优冲量耦合。

Laser radiation has been considered as one kind of feasible methods to clean space debris. Impulse coupling coefficient is an important parameter to calculate the clean effects. An analytical model for calculating laser ablation impulse coupling coefficient is put forward. The impulse coupling coefficients in vapor mechanism and plasma mechanism are connected by the ionization fraction. Therefore, a unified model of impulse coupling coefficient is set up. The relationship of laser intensity, ionization fraction and impulse coupling coefficient is obtained with A1, the most common material of space debris, as the calculation example. The transition between vapor mechanism and plasma mechanism progressively changes with the increase of laser intensity. The ionization fraction is also increasing until the vapor is totally ionized. The impulse coupling coefficient increases at first, then reaches the maximum, and decreases at last. The optimum impulse coupling coefficient is obtained when the plasma mechanism dominates.