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题名	飞秒激光诱导电晕放电及离子风的研究
作者	杜盛喆
文献子类	硕士
导师	王铁军
关键词	飞秒激光 femtosecond laser pulse 光丝 filamentation 电晕放电 corona discharge 有限元计算 finite element analysis 离子风 ionic wind
其他题名	Research on the femtosecond laser guided corona discharge and ionic wind
英文摘要	飞秒激光具有脉宽短、峰值功率高的特点，自诞生以来一直备受广大科研工作者的关注，其中，关于强飞秒激光脉冲在空气中的传输的课题也一直是强场激光物理领域的热点之一。强飞秒激光脉冲在空气中传输会出现成丝现象，主要是由于克尔自聚焦效应和等离子体散焦效应之间的动态平衡，从而可以形成一条连续的等离子通道。 许多研究工作均表明飞秒光丝通道内有大量的自由电子和离子，具有良好的导电性，因此科学家提出激光引雷的概念，试图用强的飞秒激光在空气中形成一条较长的、连续性好的等离子体通道，用以引导闪电中巨大的电流沿通道安全地导入地面。此外，飞秒光丝还被建议应用于人工影响天气、LIBS技术、THz辐射等领域，因此飞秒激光成丝具有重要的研究意义。 本论文首先介绍了飞秒激光成丝和电晕放电等物理现象，并分析了飞秒激光在空气中成丝的物理过程和飞秒光丝的一些基本性质。随后重点介绍了飞秒光丝诱导电晕放电实验，并提出了一种新颖的电极设计方法，新设计的球形电极能够解决之前实验中的一些弊端，例如在电极表面产生额外电晕区。此外还通过理论模拟和实验两种方式分析了新电极和传统电极中飞秒光丝尖端诱导电晕放电空间电场的不同分布情况，并对比了两种情形下飞秒光丝尖端附近电晕放电的起晕电场阈值的不同。最后重点介绍了一种利用飞秒光丝诱导电晕放电产生离子风的新方法，类比金属电极的电晕放电过程给出了飞秒光丝诱导产生离子风的理论解释，并实验研究了飞秒光丝诱导产生离子风的流速值和分布。; The ultrashort duration and extremely high peak power of femtosecond lasers have attracted great interests of scientists since the technology was invented. And the issue of the propagation of femtosecond pulses in the air was one of the hotspots in the field of high field laser physics. When high peak-power femtosecond pulses were propagated in air, a long plasma channel called femtosecond laser filament would form due to the dynamic equilibrium between self-focusing from Kerr effect and defocusing from self-generated plasma. A number of nonlinear effects, such as intensity clamping, conical emission, self-phase modulation and so on, can also be observed during the formation of femtosecond laser filament. Many studies have shown that femtosecond laser filament has excellent conductivity because of a huge bulk of freely moving electrons and charged ions inside the filament. Femtosecond laser pulses triggered lightning was proposed. The idea was to guide the lightning current into ground by a plasma channel, which was formed by focusing femtosecond laser pulses in the atmospheric air. Beside this, femtosecond laser filament was also found many applications such as artificial weather modification, laser induced breakdown spectroscopy and so on. Therefore it is worth to study the physics of laser filament and explore its new applications. In this thesis, the physical phenomenon of the filament and corona discharges were introduced at the very beginning. Then the mechanism and characters of filamentation were summarized, respectively. It is followed by the experiments on the laser filament guided corona discharge. A brand new design of the electrode was proposed for efficiently coupling with plasma filament. The difference between the newly designed spherical electrode and traditional cone electrode are investigated by performing numerical analysis and conducting a series of experiments. The corona discharge threshold and the special distributions of electric field are systematically investigated. At last, a new method that to generate ionic wind by laser-induced positive corona discharge was presented. Systematical investigation of the ionic wind was performed both experimentally and theoretically. In analogy with metal electrode generated ionic wind, a possible explanation of the ionic wind induced by filament-guided corona discharge was proposed.
学科主题	光学工程
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/30923]
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	杜盛喆. 飞秒激光诱导电晕放电及离子风的研究[D].

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