Electron Energy Distribution and Optical Characteristics of a Hollow Cathode Discharge

A model is proposed for the formation of the electron energy distribution in a hollow cathode discharge. On the basis of this model, an integral equation has been derived to calculate the electron distribution function over the entire cathode cavity volume. The equation holds true for both the isotropic distribution, and the case when the local distribution function is anisotropic. Solutions of the kinetic equation obtained are presented, for electron energies over 2–3 eV and up to the cathode fall potential. It is shown that the electron energy distribution function in this interval determines the optical characteristics of the hollow cathode discharge. A comparison is given of the calculated and measured radiation powers for the cases of the hollow cathode discharge in xenon and carbon dioxide. The discrepancy between the theoretical and experimental data does not exceed 20%.     

Transition of Discharge Mode of a Local Hollow Cathode Discharge

The discharge characteristics of hollow cathode discharge in argon in a cylindrical cavity are investigated experi- mentally. The voltage-current （V - I） characteristics and the light emission are measured. It is found that the discharge plasma is localized inside the hollow cavity, with an extensive Faraday dark space between the cathode and the anode. The discharge develops from predischarge to abnormal glow discharge, the hollow cathode effect （HCE） and a hybrid mode as the discharge current increases. The onset of the HCE is found for the first time by the transition from abnormal glow discharge together with a significant decrease in the slope of the V - I curve which shows a positive differential resistivity. The voltage increases proportionally with the current when the HCE is reached.     

Electron Energy Function Distribution in Hollow Cathode Discharge at Resonant Irradiation

Abstract

The behaviour of electron energy function distribution in hollow cathode discharge at resonant light irradiation is analyzed. The function is calculated for energies near and higher than the energy excitation ?₁ of the hellium metastable levels. It turns out that the electron energy function distribution is essentially influenced in the vicinity of point ?₁.     

Influence of the Anode of a Non-Self-Sustained Glow Discharge with a Hollow Cathode on the Spatial Distribution of Plasma Concentration

Russian Physics Journal - The results of investigation of the influence of geometrical dimensions, shape and position of the anode of a high-current non-self-sustained glow discharge with a hollow...     

用于真空弧等离子体放电阴极温度场测量的多光谱高温计

阴极表面温度是真空弧等离子体放电过程中一个重要参数,对真空弧等离子体的形成、电极腐蚀预测、热传导以及离子源的寿命都有重要影响。真空弧离子源的阴极具有目标小,放电过程快等特点,其温度的测量,对于时间分辨率和空间分辨率要求都很高,阴极表面温度的测量技术的欠缺,使得仅靠理论解析获得的结果难以得到验证。并且等离子体放电过程中测量仪器极易受到弧光的影响,如何避免放电过程中等离子体的辐射也是采用辐射法测量阴极表面温度要考虑的问题。这无疑给其温度场的测试研究带来困难。针对脉冲真空弧等离子体开展阴极表面温度测试实验有着重要意义,在分析了真空弧等离子体放电特性以及背景辐射特性和等离子体放电阴极测温的实际需求,本文基于高速CCD相机研制了一种新型的多光谱高温计。该高温计采用单色高速CCD相机,主要避免RGB彩色相机不能完全滤除背景辐射的弧光。为使用单色CCD相机实现多光谱辐射测温,设计了高温计的光学系统,该系统采用4孔径分光系统。将4种不同波长的滤光片嵌入到1个滤光片中。该研究设计的高温计可用于2 000~6 000 K的等离子体温度测量。并在中国工程物理研究院电子工程研究所进行现场测试,测试过程中将研制的高温计,通过外部触发形式对等离子体放电过程进行跟踪拍摄,高温计完全拍摄到等离子体放电过程。利用真空弧等离子体金属电极阴极放电的实测数据对高温计进行了验证。实验结果表明,设计的新型多光谱高温计能够用于测量真空弧等离子体放电时阴极温度场信息,测量的温度值低于放电电极的沸点温度,与等离子体放电过程中出现气化现象相符,说明高温计测的是等离子体放电阴极的温度。     

Plasma Generation in a Pulsed Mode of a Non-Self-Sustained Arc Discharge with a Hybrid Hot-and-hollow Cathode

Russian Physics Journal - The results of investigation of pulsed burning modes of a non-self-sustained arc discharge with a combined hot-and-hollow cathode are presented. The principal discharge...     

Optical Probing of the Electron Energy Function Distribution in a Photoresonant Hollow Cathode Discharge

Optical probing of electron gas in photoresonant negative glow is considered. By monitoring the spectral line intensity it can be concluded that the transfer of excitation energy to the probe atoms is mainly due to the electron gas.     

Generation of Plasma with Increased Ionization Degree in a Pulsed High-Current Low-Pressure Hollow Cathode Discharge

Russian Physics Journal - The paper presents the results of research of the processes of generation of pulsed beam-plasma formations in a high-current non-self-sustained glow discharge with a...     

同轴空心阴极氦等离子体的电子激发温度研究

利用同轴空心阴极放电装置,产生氦低温等离子体。通过对等离子体的发射光谱进行测量和计算,研究放电功率以及氦气压强对等离子体的电子激发温度的影响。结果表明:氦低温等离子体的发射光谱主要由连续谱和原子谱线构成,放电功率和压强对谱线的强度具有明显影响。压强的变化不仅影响电子从电场中获得的能量,还会影响电子与原子的碰撞频率,从而导致电子激发温度随着氦气压强的增大,出现先上升后下降的变化趋势。     

Atom and Ion Temperatures in a Hollow Cathode Discharge

Abstract

The excitation temperatures of atoms and ions /Ar I, Ar II, V I, V II, Cr I, Cr II, Cu I, and Si I/ have been measured in the hollow cathode discharge. The Ar I high energy levels have been found to be overpopulated. The electron density has been estimated. The ionization-excitation mechanism has been discussed.     

On the Populations of Neon Levels in the Low Temperature Plasma of a Hollow Cathode Discharge

Atomic levels population measurements constitute an essential contribution to various aspects of plasma research: balance and cross-section of inelastic processes, admixtures effects on level excitation mechanism, purposeful optimisation of plasma parameters etc. Atomic level populations in the negative glow of a hollow cathode discharge are of utmost interest in view of the peculiarities of the spectral source: a rich spectrum consisting of gas lines, lines of the cathode material and also lines of the substances introduced in the discharge; intensive atomic and ionic lines of high excitation potentials; small spectral linewidth, convenient for analytical purposes.     

Plasma Parameters Near a Hollow Rectangular Cathode

Journal of Applied Spectroscopy - A single probe method is used to obtain the electron density and electron energy distribution function in a short discharge gap between a rectangular hollow...     

Magneto-Galvanic Resonances in Hollow Cathode Discharge Lamps

The galvanic behavior of a hollow cathode discharge versus an external weak magnetic field is investigated. The application of this field leads to disordering of the self-aligned states, which is detected as a resonance in the discharge current, named the magneto-galvanic signal. A correlation magneto-galvanic signal–operating voltage-current point is established and attributed to Penning ionization. The contribution of the metastable Ne I 1 s₅ to the magneto-galvanic resonance is also verified.     

Microstructure and Deuterium Retention of Tungsten Deposited by Hollow Cathode Discharge in Deuterium Plasma

Tungsten has been chosen as one of the most promising candidates as the plasma-facing material in future fusion reactors. Although tungsten has numerous advantages compared with other materials, issues including dust are rather difficult to deal with. Dust is produced in fusion devices by energetic plasma-surface interaction. The re-deposition of dust particles could cause the retention of fuel atoms. In this work, tungsten is deposited with deuterium plasma by hollow cathode discharge to simulate the dust production in a tokamak. The morphology of the deposited tungsten can be described as a film with spherical particles on it. Thermal desorption spectra of the deposited tungsten show extremely high desorption of the peak positions. It is also found that there is a maximum retention of deuterium in the deposited tungsten samples due to the dynamic equilibrium of the deposition and sputtering process on the substrates.     

The Hollow Cathode Discharge as a Spectrochemical Emission Source

Abstract

The hollow cathode discharge (HCD), a specialized type of glow discharge, has been the subject of investigations by physicists (in particular) and chemists for over a half century. Several hundred literature reports may be found concerning various aspects of the HCD. Despite this, many analytical chemists today would consider the HCD as merely a sharp line source for atomic absorption spectrometry (AAS). While this is certainly its most important present application, the HCD has a long history as a spectrochemical emission source allowing direct excitation and analysis of samples. Excellent sensitivities have been reported, but experimental difficulties, including construction of a demountable hollow cathode tube, have limited overall past acceptance of the HCD as an analytical emission technique. However, the current interest by analytical spectroscopists in new methods of atomization and excitation has revived interest in glow discharges. Also, the commercial availability of two demountable hollow cathode tubes and associated vacuum systems now allows easy accessibility to the technique.     

空心阴极光源在原子发射光谱分析中的应用

本文介绍了空心阴极光源发射光谱分析中用地测定痕量元素的特点,供电电源的种类,阴极灯及电极,载气的选择等。并介绍了空心阴极光源在痕量分析上的应用。     

Influence of the Discharge Burning Conditions on Distributions of the Parameters of Plasma Generated in a Non-Self-Sustaining Glow Discharge Inside a Hollow Cathode

Russian Physics Journal - The parameters of the plasma of a non-self-sustaining glow discharge generated inside a metal hollow cathode 300 mm long and 25 mm in inner diameter are investigated. A...     

Synthesis of Nano-Crystalline Graphite Films in Hollow Cathode Discharge

The results of experiments on the production of nano-crystalline graphite films in the hollow cathode discharge on Ni(111)/sapphire substrate are presented. The characteristics of the discharge for different gases and pressures are given. The emission spectra of the plasma have been measured. The layers of the deposited graphite have been characterized by the methods of Raman scattering and atomic force microscopy. The field emission of nano-crystalline graphite was also measured. The produced layers have good homogeneity and high value of the electron field emission. The presence of vertically growing graphene is revealed.     

Pulsed Non-Self-Sustained Arc Discharge in Extended Hollow Anode

Russian Physics Journal - The paper investigates physical properties of a pulsed arc discharge of low (≈1 Pa) pressure created in argon by a plasma source with the thermionic and hollow...