非平衡态Ti-H等离子体发射光谱的双温度诊断研究

Two-Temperature Diagnostic Studies by Emission Spectra for Nonequilibrium Ti-H Plasma

单次脉冲工作的真空弧离子源,采用金属钛吸附氢形成的Ti-H固溶体作阴极,生成的等离子体同时包含金属钛和氢的成分,且在径向、横向以及时间尺度上都存在梯度,整个体系处于非平衡状态,不能用一个统一的温度来描述。假设由电子组成的子系统和由其他重粒子组成的子系统分别达到平衡,即Ti-H等离子体由电子温度和重粒子温度两个温度来描述,为双温度等离子体。采用Culdberg-Waage解离方程和Saha电离方程分别对系统中的分子解离和原子电离过程进行描述,结合等离子体电荷准中性条件,同时引入原子发射光谱这一无干扰的等离子体诊断方法,对Ti-H等离子体的温度和粒子数密度进行诊断。在MATLAB环境下,同时考虑金属Ti原子和一价Ti离子的电离,计算结果显示:根据谱线的斯塔克展宽确定的电子密度进行计算,除重粒子温度和氢气分子的数密度之外,其他的参数均可得到较准确的诊断结果;电子密度数值的准确性对计算结果有很大的影响;如果能够在计算之前确定重粒子温度,则可对Ti-H等离子体的温度和粒子数密度进行准确的定量分析。

Using the T-H solid solution made by titanium absorbed hydrogen as the cathode,the Ti-H plasma produced by the pulsed vacuum arc ion source was nonequilibrium：it contained both the component of titanium and hydrogen;there existed gradient in the radiaL,the horizontal and the time.As a result,it could not be described by a single temperature.The present paper assumed that the subsystem consisting of electrons and the subsystem consisting of other heavy particles reached equilibrium respectively,meaning that the Ti-H plasma was described by the two temperatures as electron temperature and heavy ion temperature,it was non-equilibrium two-temperature plasma.Using Culdberg-Waage dissociation equation to describe the molecular dissociation process in the system,using Saha ionization equation to describe the atomic ionization process,combining plasma＇s charge quasi-neutral condition and introducing atomic emission spectroscopy as a plasma diagnostic method which would not interfere the plasma at the same time;the temperature and the particle number density of the Ti-H plasma were diagnosed.Using MATLAB as a tool,both the titanium atoms and monovalent titanium ions＇ ionization were considered,and the calculated results showed that with the electtron density determined by the Stark broadening of spectral lines in advance,except the heavy particle temperature and the hydrogen number density,the Ti-H plasma＇s parameters could be diagnosed fairly accurately;the accuracy of the electron density values had a great effect on the calculation results;if the heavy particle temperature could be determined in advance,the temperature and the particle number density of the Ti-H plasma could be accurately analyzed quantitatively.