NBI双潘宁离子源参数的静电探针测量

介绍了静电探针在22cm双潘宁离子源中心等离子体参数测量中的应用.测出了探针的伏安特性曲线,由该曲线求出在弧流为200 A时,电子温度约为6.0 eV,密度约为2×1012 cm-3,这对于调整放电控制条件,获得高效率大功率的离子源有重要的参考价值,并且对于今后实现强而且均匀的中性束束流的引出也有着重要意义.     

离子灵敏探针及其在磁镜装置中的应用

使用离子灵敏探针对MM-2U简单磁镜装置中等离子体的离子温度和电子温度进行了测量。描述了这种静电离子探针的工作原理及主要的设计参数,对从探针特性曲线得到的离子温度及密度也予以讨论。     

离子灵敏探针及其在磁镜装置中的应用

使用离子灵敏探针对MM-2U简单磁镜装置中等离子体的离子温度和电子温度进行了测量。描述了这种静电离子探针的工作原理及主要的设计参数。对从探针特性曲线得到的离子温度及密度也予以讨论     

双等离子体源能量分散度的测量装置

本文介绍了一种静电减速透镜测量离子源能量分散度(简称能散度)的方法,给出了分辨率达10~4的减速透镜的主要参数,同时对双等离子体源能散度作了初步的实验研究。     

HL-1M装置边缘等离子体特性研究

边缘和芯部等离子体的同时控制对优化托卡马克等离子体性能是重要的。边缘等离子体密度、温度和空间电位等通常采用朗缪尔静电探针测量,而旋转速度可用马赫探针测量。好的加料技术对于获得高性能等离子体也很重要,在HL-1M装置上已开展了8发弹丸注入和分子束注入(MBI)加料实验,它能使等离子体产生中空的温度和电流密度分布,并容易获得高密度和良好的约束。本文主要介绍在低杂波电流驱动(LHCD)、多发弹丸注入和MBI三种典型放电中边缘等离子体参数的测量结果。     

基于微机电系统技术的薄膜离子源制备与实验研究

基于微机电系统技术的薄膜离子源是芯片型中子发生器的关键部件。本文通过在陶瓷基底上制备图形化钛膜并利用3层陶瓷重叠的方法获得了薄膜离子源样品,采用平板探针法和激光共聚焦显微镜得到了薄膜离子源的离子电流及其电极烧蚀特性,并进一步利用高速相机和光谱仪得到了薄膜离子源的放电发光演化图像和等离子体组分信息,最后基于实验结果分析揭示了薄膜离子源放电的工作机制。     

基于静电探针诊断下离子源调制放电

介绍了在静电探针测量下,离子源调制放电闭环控制系统设计要求,讨论了该系统的硬件设计、软件设计及其工作原理,给出了部分实验结果.系统成功地应用于实验并获得初步实验结果,为以后中性束注入开展相关物理实验提供可靠保障.     

基于微机电系统技术的薄膜离子源制备与实验研究

基于微机电系统技术的薄膜离子源是芯片型中子发生器的关键部件。本文通过在陶瓷基底上制备图形化钛膜并利用3层陶瓷重叠的方法获得了薄膜离子源样品,采用平板探针法和激光共聚焦显微镜得到了薄膜离子源的离子电流及其电极烧蚀特性,并进一步利用高速相机和光谱仪得到了薄膜离子源的放电发光演化图像和等离子体组分信息,最后基于实验结果分析揭示了薄膜离子源放电的工作机制。     

15cm双潘宁离子源等离子体产生器

介绍研制的１５ｃｍ双潘宁离子源等离子体产生器的结构和工作原理，研究了磁场、气压和弧功率等运行参数对源特性的影响，最后结合朗缪尔探针测量结果进行了讨论。该产生器的探针饱和离子流密度已达到２００ｍＡ／ｃｍ２以上，引出面附近的离子密度径向不均匀度＜±５％，噪声水平＜±１０％。     

离子源研究中的光谱诊断

在离子源研究中,光谱分析作为一种重要的实验手段具有不可替代的优越性和便利性.作为一种非接触式的等离子体诊断手段,光谱分析可以在不影响离子源放电工作状态的前提下,对离子源放电等离子体的有关参数迅速作出测量和判断.本文列举了光谱诊断方法在离子源研究中的几种典型应用.     

Discharge Characteristics of Large-Area High-Power RF Ion Source for Positive and Negative Neutral Beam Injectors

A large-area high-power radio-frequency(RF) driven ion source was developed for positive and negative neutral beam injectors at the Korea Atomic Energy Research Institute(KAERI). The RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of high-power RF discharge. Plasma ignition of the ion source is initiated by the injection of argongas without a starter-filament heating, and the argon-gas is then slowly exchanged by the injection of hydrogen-gas to produce pure hydrogen plasmas. The uniformities of the plasma parameter,such as a plasma density and an electron temperature, are measured at the lowest area of the driver region using two RF-compensated electrostatic probes along the direction of the shortand long-dimensions of the driver region. The plasma parameters will be compared with those obtained at the lowest area of the expansion bucket to analyze the plasma expansion properties from the driver region to the expansion region.     

Analysis of the characteristics of the plasma of an RF driven ion source for a neutral beam injector

A radio frequency(RF)driven ion source is a very important component of a neutral beam injector for large magnetic confinement fusion devices.In order to study the key technology and physics of an RF driven ion source for a neutral beam injector in China,an RF ion source test facility was developed at the Institute of Plasma Physics,Chinese Academy of Sciences.In this paper,a two-dimensional fluid model is used to simulate the fundamental physical characteristics of RF plasma discharge.Simulation results show the relationship of the characteristics of plasma(such as electron density and electron temperature)and RF power and gas pressure.In order to verify the effectiveness of the model,the characteristics of the plasma are investigated using a Langmuir probe.In this paper,experimental and simulation results are presented,and the possible reasons for the discrepancies between them are given.This paper can help us understand the characteristics of RF plasma discharge,and give a basis for further R&D for an RF ion source.     

Gas pressure effect on plasma transport in a magnetic-filtered radio-frequency plasma source

Volume negative ion production relies on a magnetic filter(MF), where the plasma downstream of the MF is characterized by a strip-like pattern that consists of a bright and dense plasma region. In this work, we study, in a radio-frequency plasma source, the effects of operating pressure on this strip. This investigation, conducted using a Langmuir probe, shows that the plasma uniformity might be controlled through the gas pressure. Moreover, the operating pressure determines on which hemi-cylinder(side of magnetic field lines) the strip forms. This side inversion of the high-density plasma hemi-cylinder is due to an inversion of an ambipolar electric field that changes the E?×?B drift direction.     

Deuteron Beam Source Based on Mather Type Plasma Focus

A 3 kJ Mather type plasma focus system filled with deuterium gas is operated at pressure lower than 1 mbar. Operating the plasma focus in a low pressure regime gives a consistent ion beam which can make the plasma focus a reliable ion beam source. In our case, this makes a good deuteron beam source, which can be utilized for neutron generation by coupling a suitable target. This paper reports ion beam measurements obtained at the filling pressure of 0.05–0.5 mbar. Deuteron beam energy is measured by time of flight technique using three biased ion collectors. The ion beam energy variation with the filling pressure is investigated. Deuteron beam of up to 170 keV are obtained with the strongest deuteron beam measured at 0.1 mbar, with an average energy of 80 keV. The total number of deuterons per shot is in the order of 10¹⁸ cm^?2.     

Ion source plasma parameters measurement based on Langmuir probe with commercial frequency sweep

Langmuir probe is one of the main diagnostic tools to measure the plasma parameters in the ion source. In this article, the commercial frequency power, which is sine wave of 50 Hz, was supplied on the Langmuir probe to measure the plasma parameters. The best feature of this probe sweep voltage is that it does not need extra design. The probe I-V characteristic curve can be got in less than 5 ms and the plasma parameters, the electron temperature and the electron density, varying with the time can be got in one plasma discharge of 400 ms.     

Bended probe diagnostics of the plasma characteristics within an ECR ion source with a rectangular waveguide

To reveal the argon plasma characteristics within the entire region of an electron cyclotron resonance(ECR) ion source, the plasma parameters were diagnosed using a bended Langmuir probe with the filament axis perpendicular to the diagnosing plane. Experiments indicate that,with a gas volume flow rate and incident microwave power of 4 sccm and 8.8 W, respectively,the gas was ionized to form plasma with a luminous ring. When the incident microwave power was above 27 W, the luminous ring was converted to a bright column, the dark area near its axis was narrowed, and the microwave power absorbing efficiency was increased. This indicates that there was a mode transition phenomenon in this ECR ion source when the microwave power increased. The diagnosis shows that, at an incident microwave power of 17.4 W, the diagnosed electron temperature and ion density were below 8 eV and 3?×?10~(17) m~(-3), respectively, while at incident microwave power levels of 30 W and 40 W, the maximum electron temperature and ion density were above 11 eV and 6.8?×?10~(17) m~(-3), respectively. Confined by magnetic mirrors, the higher density plasma region had a bow shape, which coincided with the magnetic field lines but deviated from the ECR layer.     

Measurement of Ion Parameters by Ion Sensitive Probe in ECR Plasma

Ion parameters in electron cyclotron resonance (ECR) microwave plasma were measured by ion sensitive probe and were compared with the electron parameters obtained by double Langmuir probe. The effects of gas pressure and microwave power on the ion temperature and density were analyzed. The spatial distribution of the ion parameters was also investigated by the ion sensitive probes with a tunable radial depth installed on different probe windows along the chamber axis. Results showed that the ion density measured by the ion sensitive probe was in good agreement with the electron density measured by the double Langmuir probe. The influence of gas pressure on the ion parameters was stronger than that of microwave power. With the increase in working pressure, the ion temperature decreased monotonously with a decreasing rate larger than that at higher pressure. The ion density first increased to a peak (42.3?1010cm-3) at 1 Pa and then decreased. The ion temperature and density increased little with the increase in the microwave power from 400 W to 800 W. The plasma far away from the resonant point is found to be radially uniform.     

Study of axial double layer in helicon plasma by optical emission spectroscopy and simple probe

In this work we used a passive measurement method based on a high-impedance electrostatic probe and an optical emission spectroscope (OES) to investigate the characteristics of the double layer (DL) in an argon helicon plasma.The DL can be confirmed by a rapid change in the plasma potential along the axis.The axial potential variation of the passive measurement shows that the DL forms near a region of strong magnetic field gradient when the plasma is operated in wavecoupled mode,and the DL strength increases at higher powers in this experiment.The emission intensity of the argon atom line,which is strongly dependent on the metastable atom concentration,shows a similar spatial distribution to the plasma potential along the axis.The emission intensity of the argon atom line and the argon ion line in the DL suggests the existence of an energetic electron population upstream of the DL.The electron density upstream is much higher than that downstream,which is mainly caused by these energetic electrons.