基于静电探针测量对双潘宁离子源的弧特性研究

本文介绍了采用静电探针的逐点测量法和锯齿波扫描测量法来测量离子源放电中等离子体参数,在此基础上利用静电探针所测量的离子饱和流信号作为控制部分反馈变量,使用闭环控制对22厘米双潘宁离子源的等离子体进行调节,并且利用探针所测量的结果对弧特性进行了初步的分析.     

强流双潘宁离子源弧特性研究

针对22cm双潘宁离子源,研究了其弧流与放电调节参数的关系以及二次进气的效果,确定了拉长弧流脉宽、提高弧流强度与稳定性、达成离子源合适工作状态的措施,为获得高品质的弧流提供了依据.离子源弧特性测试研究结果对提高强流离子源的工作性能以实现NBI系统强流准稳态运行有重要的指导意义.     

火花氢离子源的等离子体特性研究

提出了氢离子源等离子体的一维动态CRAM（collisional radiative atomic and molecular）模型，计算了非平衡态（NTE）下等离子体中分子、电子、离子、基态原子、激发态原子共9种粒子浓度以及电场强度、气体温度和电子温度在一个脉冲内随时间和轴向空间的分布。计算表明：氢离子源中粒子分布在轴向极不均匀，阳极附近有很高的粒子浓度；氢原子离子占总离子数的93．9％，与文献值相符；巴耳末系谱线强度与文献值符合较好。     

电子回旋共振等离子体源的特性

简要描述了一台频率为２．４５ＧＨｚ的电子回旋共振（ＥＣＲ）等离子体源的特性测试,结果表明,放电室内的等离子体密度和电子温度与静态磁场、微波输入功率和真空度等参数均有着密切关系。当磁场达到共振条件８７．５ｍＴ时,等离子体很易产生,但等离子体密度的最大值却出现在９３ｍＴ处。ＥＣＲ源在真空度为０．１－１Ｐａ间均能运行。由石英、Ａｌ２Ｏ３陶瓷和ＢＮ构成的微波输入窗有良好的阻抗匹配,在微波功率为２００－７０     

中子管冷阴极潘宁离子源起弧特性测试

实验建立了中子管冷阴极潘宁离子源起弧特性的测试方法。该方法采用对比实验方法对中子管离子源起弧时刻进行研究,可得到离子源起弧规律,发现同步脉冲与中子脉冲之间的差异。通过改变变量,对存在的差异进行研究,得到中子脉冲时序关系,为脉冲中子类测井仪方法研究提供数据基础。     

阴极真空弧源磁过滤弯管偏压模式研究

为了改进阴极真空弧等离子体通过磁过滤弯管的传输效率，测定了磁过滤弯管出口离子电流与阴极弧流的关系，结果表明：磁过滤弯管内表面中，靠近大径中心一侧的表面（内侧面）和远离大径中心一侧的表面（外侧面）与等离子体的相互作用是独立的，存在两种向磁过滤弯等内表面运动的离子流：离子碰撞导致的横向扩散离子流和从阴极弧出来的较高能量的惯性离子流。两种离子流通过磁过滤管的传输过程有不同的机制。整个磁过滤弯管偏压较仅仅Bilek板偏压有更高的离子传输效率，Bilek板偏压对磁过滤弯管离子传输起主要作用。     

磁过滤真空弧沉积中过滤管道的第二阳极作用研究

利用一台磁过滤真空弧沉积装置,初步研究了磁过滤管道对系统弧放电的影响。实验证明,磁过滤管道在阴极真空弧沉积中不仅起到消除大颗粒的作用,还作为阴极真空弧放电的第二阳极对弧放电产生影响。给出了磁过滤阴极真空弧放电的等效电路,并用此电路对磁过滤阴极真空弧放电中的部分实验现象进行了解释。     

电弧等离子体煤粉燃烧器的研究

利用电弧等离子体温度高、单位体积热功率密度高、化学活性高等特点,设计出了结构简单、能稳定燃烧的电弧等离子体煤粉燃烧器;这种燃烧器只需提供一定的等离子体功率,对煤粉进行气化和活化后就能和主进风产生猛烈的燃烧。经初步实验研究,这种燃烧器能稳定地燃烧,主燃烧室出口处火焰中心温度约为1150-1260℃,输入的等离子体功率与所进煤粉燃烧的热功率之比约为1:25。     

磁驱动旋转电弧运动图像及弧电压脉动的实验研究

磁驱动旋转电弧产生扩散电弧等离子体过程中有许多有趣的物理现象。本文利用高速摄影技术研究了大气压条件下、非均匀磁场中、大尺度磁驱动旋转氩电弧的电弧结构；在一定的弧电流和外磁场条件下，电弧的平面形状表现为不断发展和增长的螺旋结构，电弧螺旋结构的破裂往往产生于阴极附近的等离子体射流。采用图像分析的方法计算了外部磁场作用下阳极斑点沿弧室内壁的移动频率，分析了磁驱动旋转电弧运动过程中的弧电压脉动现象。结合电弧图像分析和电弧电压脉动及其FFT分析得出：电弧电压的大幅波动与多层电弧螺旋结构破裂和重建相关，而电弧电压的小幅波动则是弧根小幅跳动引起电弧拉长和收缩的结果。     

受控核聚变托卡马克等离子体水平位移平衡反馈控制的物理研究

在理论上系统地分析了ＨＴ－６Ｍ托卡马克等离子体水平位移平衡控制器系统的结构及其控制方式，并采用大功率ＧＴＯ斩波器作为反馈场电源和Ｂａｎｇ－Ｂａｎｇ控制模式的技术，取得了较好的成果。     

Studies on fluid model for numerical simulation of gas discharges in color plasma displays

The fluid models of gas discharge in alternating current plasma display panel (AC PDP) cell are discussed.From the Boltzmann equation, the hydrodynamic equations are derived, but this model consumes much computational time for simulation. The drift-diffusion approximation model and the local field approximation model are obtained to simplify the numerical computation, and the approximation conditions of these two models are discussed in detail. The drift-diffusion approximation model gives more satisfactory result for PDP simulation, and the expression of energy balance equation is given completely in this model.     

磁驱动滑移电弧直径的研究

大气压非热电弧的直径是确定电弧电流密度、从而确定等离子体电子密度和电子温度的重要参数之一.采用CCD摄影方法对大气压磁驱动滑移电弧在运动中的形状和尺寸进行了观察和测量,将电弧在CCD上的影像转换成灰度(光强)分布数据,对电弧图片径向上的灰度分布数据进行曲线拟合来确定电弧径向边界和直径;分别测量了电弧在运动方向的投影直径(正向直径)和垂直于运动方向上的投影直径(侧向直径),分析了电弧直径与电弧电流以及外加磁场之间的变化关系,并对电弧正向直径和侧向直径进行了对比分析.     

A Study of Variation Patterns of Shock Wave Control by Different Plasma Aerodynamic Actuations

Demonstrative experiments on the variation patterns of the position, angle, and intensity of shock wave are presented. Different means of aerodynamic actuation, such as variations of the distance between discharge channels, the number of discharge channels, the DC discharge voltage, the angle of ramp, and the application of magnetic field, in a supersonic flow of M=2.2 are employed. Results of both the schlieren and pressure test indicated that when the plasma aerodynamic actuation is applied, the starting point of the shock wave was shifted 1 to 8mm upstream on average, the shock wave angle was reduced 4% to 8% on average, and the shock wave intensity was decreased by 8% to 26%. The local plasma aerodynamic actuation could generate an extrusive plasma layer with high temperature and pressure. This plasma layer caused an upstream-shift of the separating point of the boundary layer, which changed the structure of the original shock wave. Moreover, in a simulation study, the plasma aerodynamic actuation was simplified as a thermal source term added to the Navier–Stokes equations, after all, the results obtained showed consistency with the experimental results.     

Optical properties of titanium oxide films obtained by cathodic arc plasma deposition

Structural and optical properties of nanometric titanium oxide(TixOy) films obtained by cathodic arc plasma deposition were investigated. Phase analysis by x-ray diffraction and Fouriertransform infrared spectroscopy showed the presence of anatase, rutile, Ti_2O_3, Ti_4O_7 and amorphous phases. Scanning electron microscopy images showed well-developed surface morphology with nano-patterns. Spectroscopic ellipsometry revealed film thicknesses of 53 and50 nm, variable refractive indices dependent on the light wavelength and close to zero extinction coefficients for wavelengths higher than 500 nm. On the basis of ultraviolet–visible spectroscopy data and using the Tauc equation, band gap values for direct and indirect electron transitions were determined.     

Kinetic simulation study of one dimensional collisional bounded plasma

A self-consistent kinetic simulation study of one dimensional collisional bounded plasma is presented.The formation of stable of stable sheath potential is investigated.It is found that mass ratio of electron and ion not only affects the level of sheath potential.but also affects the ion temnperature of system.It is clarified that the effects of secondary emission electron on both the total potential drop and the temperature are not important.     

Propagation properties of broadband terahertz pulses through a bounded magnetized thermal plasma

An analysis of THz waves propagation in dense, collisional, thermal, magnetized and bounded plasma is presented. By introducing the dielectric constant of a warm magnetoplasma and using the method of impedance transformation with multiple dielectrics, the coefficients of power reflection (R) and absorption (A) are derived for a bounded plasma model by a lossless plate and a conductor plate. The effects of electron temperature, collision frequency, external magnetic field, electron density and thickness of the plasma slab on the absorption coefficient are analyzed numerically. It is found that these plasma parameters can cause significant change in the value of A. Some phenomena, for example negative power absorption, upper-hybrid resonance absorption and geometric resonances absorption, are observed and the behavior of the THz wave propagation inside the plasma model is explained numerically and physically.