飞秒激光诱导负高压电晕放的研究
文献类型：学位论文
| 作者 | 张健浩 |
| 文献子类 | 硕士 |
| 导师 | 李儒新 |
| 关键词 | 飞秒激光技术 femtosecond laser pulse technology 激光光丝 laser filamentation 电晕放电 corona discharge 有限元计算 finite element analysis |
| 其他题名 | Research on femtosecond laser guided negative high-voltage corona discharge |
| 英文摘要 | 超强超短脉冲激光技术是近三十年来激光技术领域的科学前沿，其中飞秒激光及其非线性光学效应是强场激光物理领域的一个研究热点。飞秒激光成丝现象源于独特的非线性克尔光学效应，能够在光学透明的气体、液体和固体介质中形成等离子体通道，其形成的主要机制是非线性光学中的克尔自聚焦效应和等离子体散焦效应之间的动态平衡。飞秒激光成丝科学凭借其复杂神秘的物理机制和广阔的应用前景，不断引发科研人员的研究兴趣，并且已经在人工影响天气、物质检测分析、THz辐射技术等许多领域产生突破性的研究成果。 飞秒激光光丝可以在空气中保持较高的强度长距离传输，同时借助能库效应，光丝能够越过障碍传输，因此能够在恶劣环境中传输较长的距离。另外，光丝等离子体通道内具有大量的电子和离子，电子密度较高，因此具有良好的导电能力。基于这些特性，科研人员希望通过成丝技术在空气中形成一条连续的等离子体通道，来实现远距离传输电能的目的，并据此提出了许多新的概念，例如激光引雷技术、远程电能传输技术等。电晕放电是一种发生在导体尖端、边缘等局部电场强度较高处的自持放电现象，目前已广泛应用于许多领域，例如工业除尘、臭氧生成等等。飞秒激光光丝技术可以与电晕放电进行巧妙结合，是实现远距离传输电能的基础，同时也为电晕放电技术的进一步扩展提供了许多新的思路。 本论文主要对空气中飞秒激光光丝与负电晕之间相互作用的现象、特性和物理机制进行了研究。首先介绍了飞秒激光成丝和电晕放电等物理现象，并对飞秒激光在空气中成丝现象及相应的性质和物理机制进行了简要介绍。之后通过数值模拟对激光光丝与负电晕之间相互作用过程中的三维空间电场分布进行了计算分析，模拟结果表明，在飞秒激光光丝与负电晕的相互作用过程中，光丝通道末端出现了极强的电场分布，能够在局部区域引发强烈的电子雪崩效应，产生电晕放电现象。最后在数值模拟的基础上介绍了飞秒激光光丝诱导正/负高压电晕放电的实验结果，并对其区别进行了解释。重点研究了飞秒激光光丝与负电晕之间在强、弱耦合情况下的实验现象及其差异，给出了飞秒激光光丝与负电晕放电之间相互作用的理论解释，并且提出了通过改变光丝通道长度的方式来实现对负电晕作用区域进行调节控制的方法，这为实现全光调控诱导电晕放电的应用扩展提供了全新的思路。; The ultra-intense and ultra-short laser technology is one of advanced research topics. The development of femtosecond laser and its applications on nonlinear optics are the research frontiers of high-field laser physics. Femtosecond laser filamentation is a unique nonlinear optical effect, which can produce a plasma channel in various transparent medias such as solids, liquids and gases. The main mechanism of filamentation is a dynamic balance between self-focusing based on the optical Kerr effect and defocusing based on the laser-ionized plasma. Femtosecond laser filamentation attracts great research interests because of its mysterious physical mechanism and broad application prospects. Laser filamentation has found many potential applications including weather modification, substances detection and THz radiation. Femtosecond laser filamentation can deliver high intensity over long distance. Because of energy-reservoir effect, laser filament can propagate in the complex environment by bypassing obstacles. Moreover, filament has excellent conductivity due to a large number of free electrons within. Based on the above-mentioned characteristics, the concept efficiently delivering electricity power over a large distance by laser filament with long successive plasma channel in air is proposed. Many potential applications are proposed including artificially triggered lightning, electric power transmission and so on. Corona discharge is a self-sustained discharge phenomenon which generally happens at high electric field location with small curvatures such as sharp tip and edges. Corona technology has found practical applications such as on electrostatic precipitation, ozone production and so on. Therefore, it is interesting and worth to study the coupling between femtosecond laser filament and corona discharge, which is the base of delivering electricity power over a distance using filament. New applications will be expected based laser guided coronas. In this thesis, a systematic study on the interaction between femtosecond laser filament and negative corona was investigated. First of all, the fundamental physics and characteristics of the femtosecond laser filamentation and corona discharges were briefly introduced, respectively. After that, the electric field spatial distributions of the interaction between filaments and negative corona discharge were simulated. The simulated results show that by coupling the laser filament with negative corona, the electric field at around the end of laser filament is high enough to generate negative corona. And then, experimental results of femtosecond laser filament guided positive/negative corona discharge were reported after a comparatively experimental study. The phenomena of laser guided negative corona discharge differs significantly from that of a positive corona. And a physical explanation was proposed to understand this difference. Finally, the phenomena of strong/weak coupling of filaments with negative corona were reported and analyzed. And negative corona area can be altered through the control of filament length, which provides a novel method to optically guide negative corona. |
| 学科主题 | 光学工程 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/31106]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 张健浩. 飞秒激光诱导负高压电晕放的研究[D]. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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