瞬态非线性激光等离子体耦合模型下高功率激光与液滴相互作用研究

The ionization mechanism, energy deposit of laser, phase transformation and distortion of droplet and the disturbed optical field during high power laser interaction with a droplet are studied in this project. Afterward, the properties of droplets system influenced by laser with different parameters are obtained..In order to study the photoionization procedure of water, we present a nonlinear transient coupling model of laser field and its self-generated plasma, and this model can predict the laser induced breakdown threshold, the evolution of optical field and plasma, and the distribution of plasma absorption. In addition, laser interaction with aqueous medium on the influence of different molecule structure is discussed as well. The structure and the speed of shock wave and the distortion and splitting of the droplet after laser interaction with droplet can be predicted by nonlinear transient coupling model of laser-induced plasma, and hydromechanics combined with explosion mechanics, respectively. These phenomenon are measured using schlieren method..The transmission matrix of optical field is calculated by nonlinear transient coupling equations of laser-induced plasma equation. To study the properties of droplets system influenced by laser with different parameters, the interaction between laser and several droplets is considered, and the chain reaction of droplets merge is simulated. We will design the optical scattering detection system of laser-droplets interaction to realize the measurement of droplets system..The vapor transport during laser irradiated droplets is also studied for laser induced water condensation technology.

研究高功率激光作用与水介质、水边界层相互作用，研究作用液滴过程中的电离机制、能量沉积、液滴相变和变形、液滴对激光光场的反作用等，进而研究激光作用液滴集团后的液滴性质和激光参数变化的效果。.建立瞬态非线性激光等离子体耦合模型，得到激光击穿水介质的阈值及等离子对激光光场的吸收分布。研究分子构型有序度对高功率激光作用水介质的影响。利用瞬态非线性模型研究激光作用液滴后续冲击波的构型和速度；利用流体动力学和爆炸力学研究液滴受到高功率激光辐照后的变形和分裂。利用纹影法测量激光作用液滴后冲击波速度、液滴变形、激光通过单个液滴的能量通过率。.基于瞬态非线性耦合模型计算单个液滴的光场传输矩阵。研究激光与数个液滴或液滴集团的相互作用，模拟激光作用液滴产生冲并链式反应。设计并搭建激光液滴集团相互作用散射检测系统，实现激光对于液滴集团的实时检测。研究激光作用液滴的水汽输运，为激光诱导水凝结技术提供理论准备。

基于水介质的强光电离和激光光场的非线性传输方程，研究了激光等离子体和激光光场的时域演化，建立激光与液滴相互作用中等离子体耦合模型，发现并解释了皮秒激光诱导等离子体会逆着激光场方向移动的现象。研究强光在水云中的传输问题，并利用等离子体瞬态耦合模型计算云和雾对强激光光场（尤其是在光学击穿发生后的）的能量沉积。建立了单个液滴受强脉冲激光辐照的物理模型，研究了激光作用液滴过程中的电离机制、能量沉积、液滴相变和变形。.研究氙原子和氙二聚物分子的强光场电离原子和分子的主要特征、电离产生的光电子动量分布和能量分布，揭示分子强光电离之于原子强光电离的不同之处。建立了包含离子态的多电子原子强场近似理论，并以此为基础发展出二能级双心量子干涉理论。该理论可以用来预测范德瓦尔斯双原子分子特别是氙二聚物分子在强光场电离后得到的光电子的动量或能量分布.优化激光与液滴相互作用中等离子体耦合模型，对液滴击穿阈值及内部冲击波、相变以及液滴形变等多物理场进行研究。研究了单个液滴激光等离子体和光场的时空演化，研究双液滴结构对液滴光学击穿和激光等离子体的影响，以及激光能量的非线性吸收。双液滴结构可以使液滴吸收微弱的激光能量而发生击穿。开展激光在水中产生多空泡及相互作用实验研究。.本项目的研究结果可为激光大气传输、激光微外科（眼科）医学和激光干预天气系统等提供参考。