稀有气体原子电子碰撞速率系数的实验研究

发布时间：2018-06-26 10:56

本文选题：电子碰撞速率系数 + 等离子体模型　；参考：《清华大学》2016年博士论文

【摘要】：稀有气体放电被广泛应用于低温等离子体的基础研究和工业应用中。在混有稀有气体的放电中,电子碰撞过程是最主要的动力学过程之一。特别是电子与稀有气体原子第一激发态1s态碰撞发生的激发或转化过程,此类过程是稀有气体放电中活性粒子最重要的产生过程之一。因此,此类电子碰撞过程的速率系数是基础研究中必不可少的数据。然而,对于此类电子碰撞过程,仍缺乏准确的速率系数数据。为解决这一问题,本文提出了结合等离子体模型及实验诊断确定稀有气体放电中1s态粒子电子碰撞过程速率系数的方法。实验上,采用有自己特色的实验手段来调节放电状态,突出待测电子碰撞过程的重要性,并利用相应的实验诊断技术对该条件下的相关参数进行测量,再结合模型获得相关的电子碰撞速率系数。本文利用此方法确定了氩、氪等稀有气体放电中电子碰撞1s态粒子的激发或转化过程的速率系数。其创新之处体现在:一、建立了在稀有气体放电中测量电子碰撞速率系数的实验方法。首先利用脉冲放电的余辉阶段突出1s态电子碰撞过程的贡献;再者,通过设计变气压、变功率、混气等放电条件突出4个1s态中某些1s态的贡献;最后利用实验诊断确定放电参数从而获得该1s态粒子电子碰撞过程的速率系数。该实验方法能够测量多种稀有气体放电中1s态粒子的多种电子碰撞过程的速率系数。二、获得了氩、氪原子1s态粒子重要电子碰撞激发或转化过程的速率系数(58个),其中部分结果(35个)是首次在实验中获得。这些结果不但能为建立等离子体模型及发射光谱诊断的研究提供更多准确的基础数据,而且也可用于检验理论计算得到的电子碰撞速率系数。三、在对脉冲等离子体进行实验研究中,本文提出了两种在氩气脉冲放电中分别测量时间分辨电子温度和亚稳态密度的光谱诊断方法。新提出的光谱诊断方法能够适用于多种低温等离子体设备。尤其是对科学研究和工业应用等领域的许多放电设备而言,当其他诊断方法由于各种实际条件限制(如射频干扰、电离率低、设备复杂、无穿过等离子体中心的光通路等)而不能正常使用时,本文提出的方法仍能够有效地测量电子温度和氩原子亚稳态密度的时间演化。
[Abstract]:Rare gas discharge is widely used in basic research and industrial application of low temperature plasma. Electron collision is one of the most important dynamic processes in the discharge mixed with rare gases. In particular, the excitation or transformation of electrons into the first excited state 1s of a rare gas atom is one of the most important processes for the generation of active particles in rare gas discharge. Therefore, the rate coefficients of such electron collision processes are essential data in basic research. However, there is still a lack of accurate rate coefficient data for such electron collision processes. In order to solve this problem, a method for determining the electron collision rate coefficients of 1 s particles in rare gas discharge is proposed, which is based on plasma model and experimental diagnosis. In the experiment, the characteristic experimental means are used to adjust the discharge state, to highlight the importance of the electron collision process to be tested, and to measure the relevant parameters under the condition by using the corresponding experimental diagnostic technology. The relevant electron collision rate coefficients are obtained by combining the model. In this paper, the rate coefficients of the excitation or transformation of 1 s particles in the discharge of argon, krypton and other rare gases have been determined by using this method. The main innovations are as follows: first, an experimental method for measuring electron collision rate coefficient in rare gas discharge is established. Firstly, the contribution of 1s electron collision process is highlighted by the afterglow stage of pulse discharge, and the contribution of some 1s states in 4 1s states is highlighted by designing the discharge conditions such as variable pressure, variable power and gas mixture. Finally, the discharge parameters are determined by the experimental diagnosis and the rate coefficients of the electron collision process of the 1s particle are obtained. The experimental method can be used to measure the rate coefficients of various electron collision processes of 1s-state particles in a variety of rare gas discharges. Secondly, the rate coefficients (58) of the excitation or transformation process of the important 1 s particles of argon and krypton atoms have been obtained, and some of the results (35) have been obtained for the first time in the experiment. These results can not only provide more accurate basic data for the study of plasma model and emission spectrum diagnosis, but also can be used to test the electron collision rate coefficients calculated theoretically. Thirdly, in the experimental study of pulsed plasma, two spectral diagnostics methods for measuring time-resolved electron temperature and metastable density in argon pulse discharge are proposed. The new spectral diagnosis method can be used in many kinds of low temperature plasma equipments. Especially for many discharge devices in fields such as scientific research and industrial applications, when other diagnostic methods are limited by various practical conditions (such as radio frequency interference, low ionization rate, complex equipment, The proposed method can still effectively measure the time evolution of electron temperature and the metastable density of argon atoms.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O53;O461

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