具有持久磁场的ToreSupra中用D2ICRF锻炼清洗第一壁和控制 …

在超导磁聚变装置中持久磁场的应用障碍了用大多数脉冲装置中实际使用的辉光放电来进行锻炼，为此，在具有３．８Ｔ持久磁场ＴｏｒｅＳｕｐｒａ中研究了一种替代的方法，由离子回旋频率范围（ＩＣＲＦ）波注入产生放电，ＨｅＩＣＲＦ放电锻炼（ＩＣＲＦ－ＤＣ）已经证明，能有效地氘饱和和碳的第一壁去饱和，在本文，我们描述了Ｄ２ＩＣＲＦ－ＤＣ如何能用于清洗器壁，或改变其氢同位素比，这已通过抽走由ＩＣＲＦ等离子体粒子轰击产     

AVLIS离子引出收集过程的初步研究

通过理论计算研究了１－Ｄ无碰撞ＡＶＬＩＳ离子引出过程，比较了交变场与恒定场对离子引出特性的影响，计算和分析结果表明等离子体离子密度≥１０７ｃｍ（－３），屏蔽效应存在，离子的引出在振荡中完成；对相同离子密度，随电场的增加，离子引出时间有饱和趋势，比较了脉冲场与恒定场的引出效果，结论是两者的引出效果一样，而采用脉冲场可消除斯塔克效应的影响。     

静电场方法离子引出和收集特性分析

采用二维电子非平衡模型对几种静电场离子引出方法进行模拟,分析了电子非平衡模型对离子引出过程中电位的影响。模拟了不同外加电压下几种静电场收集模型的离子引出收集特性、引出时间与屏蔽剥离的关系,以及碰撞和溅射效应。改进M型电极法的离子引出时间和引出收集率均比平行板电极法的好。     

离子回旋频率范围的加热和电流驱动状态

在离子回旋频率范围（ＩＣＲＦ）发射的快声波是托卡马克等离子体的主要加热方案之一，这个加热和电流驱动方案可能有很大的灵活性，既可利用各种波－粒子相互作用机制，也可利用快波能经受到的模转换，如设计适当，ＩＣＲＦ系统能用于离子或电子加热的电流驱动，而且还有定域沉积分布的优点，几乎的有现在的托卡马克现都使用ＩＣＲＦ加热和电流驱动，而且正在为ＩＴＥＲ研究ＩＣＲＦ系统。     

引出负离子的永磁边引出PIG源

介绍了一个可引出Ｈ、Ｏ、Ｆ等负离子的永磁边引出ＰＩＧ源。在１５ｋＶ引出电压下，可获得Ｏ＾－离子１３０μＡ，Ｆ＾－，离子７５μＡ，功率消耗分别约为１１０、２８０Ｗ。     

永磁端引出溅射PIG源进展

介绍了永磁端引出溅射ＰＩＧ离子源的进展状况，通常它可用于引出气体的与金属的单或多电荷离子，在２０－３０ｋＶ的引出电压下，可引出ｍＡ级的气体离子和数十微安的金属离子，功耗小于５０Ｗ。同时也可用于直接引出某些电子亲合势料强的气体元素，如，Ｈ，Ｏ，Ｆ等的负离子。     

托卡马克电场漂移电子注入的物理分析研究

对电场漂移电子注入中的电子束物理,电子注入情况下手 马克等离子的平衡,电子注入器中的物理问题等进行了分析研究。结果表明,漂移电子束的稳定条件是外加电场必须大于电子束本身所产生的电场;为了保持等离子体环的平衡,外加电压愈低愈好;     

磁镜装置中等离子体加热的实验研究

给出了在简单磁镜装置MM-2及其改进装置MM-2U中电子回旋共振加热(ECRH)和离子回旋共振加热(ICRH)的实验结果。在电子回旋共振加热的实验中,使用一个频率为15GHz,功率约为30kW的微波源,建立了热电子温度为140～170kev的热电子环,这是半径为7～10cm,空间分布为一个非封闭的环。在离子回旋共振加热实验中,使用一个频率为4.81MHz,功率为40kW的射频源,对ECR等离子体进行离子回旋共振加热,观测到离子与电子受到了不同程度的加热,离子温度由原来的平均3eV升到8eV,电子温度由原来的平均20eV升到30eV,且等离子体电位及等离子体的约束特性均有所改变。     

聚变高功率RF技术在非聚变领域的应用

本文介绍了在几ＭＨｚ到几ＧＨｚ（微波频率）的频率范围内高功率射频技术应用的几个例子。所有例子都涉及到在用于许多重要的技术工艺时非聚变等离子体的ＲＦ产生。一些具体的项目是：用于此出离子束的感应驱动ＲＦ放电、射频板反应器以及最近发展起来的微波等离子体源。     

DⅢ—D托卡马克的初步振荡通量电流驱动实验

在ＤⅢ－Ｄ托卡马克上作了振荡通量螺旋性注入的初步实验。环向通量受编程等离子体拉长的调制。不直接编程表面电压，而是用在一定相移下的周期调制将等离子体电流编程。从螺旋性注入的角度讨论了，并且也通过调制等离子体横越场的运动引入了这种调制的理论原理。由于初级绕组与等离子体电流充分耦合，所以拉长的幅度和相位受等离子体电流变化的影响，其行为与编程的不一样。由于这个原因，螺旋性注入感应的电压较低，故本实验没有试     

Ion Extraction Characteristics from Photoionized Plasma by Radio-Frequency Resonance Method

In order to raise ion extraction efficiency in laser isotope separation, we have developed a radio-frequency (rf) resonance method. Then, to confirm feasibility of this method to a photoionized plasma, we experimentally studied the ion extraction characteristics.

When the rf frequency was swept under a weak magnetic field (5mT), the plasma-sheath resonance was found to occur at about 12MHz which was almost the same value as the theoretical one. Moreover, it was confirmed that the ion extraction time at the resonance frequency became the minimum.

When the magnetic field strength decreased from 5mT to zero, the ion extraction time became long. From the simulation results, this was because the plasma potential decreased with the magnetic field strength. Therefore, a magnetic field strength of more than 1mT was required to obtain a sufficient ion extraction efficiency.

To obtain the same extraction time as when applying a ?3kV dc voltage in the electrostatic method, the rf resonance method needed a voltage more than 70V_rms, in which the dc bias was ?1kV. Therefore, we confirmed that this method is feasible for the ion extraction from the photoionized plasma.     

Observation of low-frequency oscillation in argon helicon discharge

We present here a kind of low-frequency oscillation in argon helicon discharge with a half helical antenna. This time-dependent instability shows a global quasi-periodic oscillation of plasma density and electron temperature, with a typical frequency of a few tens of Hz which increases with external magnetic field as well as radiofrequency(RF) power. The relative oscillation amplitude decreases with magnetic field and RF power, but the rising time and pulse width do not change significantly unde...     

Progress of the RF negative hydrogen ion source for fusion at HUST

Huazhong University of Science and Technology has developed an experimental setup of a radio frequency (RF) driven negative hydrogen ion source, to investigate the physics of production and extraction of the H− ions for neutral beam injection in nuclear fusion reactors. The main design parameters of the ion source are: RF power ≤40 kW; extraction voltage ≤10 kV; accelerator voltage ≤20 kV. This paper gives an overview of the progress of the ion source with particular emphasis on some issues. The RF driver and source plasma are analyzed and optimized in terms of impedance matching, plasma characteristics and power coupling. In regard to the simulation analysis, a plasma model based on the particle-in-cell method and a beam trajectory model considering beam stripping loss are developed to investigate the plasma and negative ions transport inside the ion source. Furthermore, a collisional radiative model of H and H2 is built for plasma optical diagnosis.     

Estimation of the sheath power dissipation induced by ion cyclotron resonance heating

During ion cyclotron resonance heating, the sheath power dissipation caused by ion acceleration in the radio frequency(RF) sheath is one of the main causes of RF power loss in the tokamak edge region. To estimate the power dissipation of an RF sheath in the ion cyclotron range of frequency(ICRF), a 1 D fluid model for the multi-component plasma sheath driven by a sinusoidal disturbance current in the ICRF is presented. By investigation of the sheath potential and ion flux at the wall, it is shown that the larger frequency and lower amplitude of the disturbance current can cause smaller sheath power dissipation. The effect of the energetic ion on the sheath power dissipation depends on the disturbance current. For large amplitude of disturbance current, the increase in the concentration and energy of the energetic ion leads to a decrease in sheath power dissipation. While for a small disturbance current, the sheath power dissipation demonstrates non-monotonic variation with the concentration and energy of the energetic ion. In addition, the sheath power dissipation is found to have a small increase in the presence of light impurity ions with low valence.     

Effect of gas pressure on ion energy at substrate side of Ag target radio-frequency and very-high-frequency magnetron sputtering discharge

The effect of gas pressure on ion energy distribution at the substrate side of Ag target radio-frequency (RF) and very-high-frequency (VHF) magnetron sputtering discharge was investigated. At lower pressure, the evolution of maximum ion energy (E) with discharge voltage (V) varied with the excitation frequency, due to the joint contribution of the ion generation in the bulk plasma and the ion movement across the sheath related to the ion transit sheath time τi and RF period τ_RF. At higher pressure, the evolution of E–V relationships did not vary with the excitation frequency, due to the balance between the energy lost through collisions and the energy gained by acceleration in the electric field. Therefore, for RF and VHF magnetron discharge, lower gas pressure can have a clear influence on the E–V relationship.     

高性能全永磁ECR离子源LAPECR2的研制

研制了一台体积和重量都较大、设计性能较高的全永磁电子回旋共振(Electron cyclotron resonance,ECR)离子源LAPECR2(Lanzhou all permanent magnetic ECRion source No.2 ).该离子源将用于中国科学院近代物理研究所320 kV高压平台,为其提供强流高电荷态离子束流.LAPECR2的研制采用全新的全永磁磁体结构设计,通过采用高性能的NdFeB永磁材料、优化的磁结构设计以及精确的计算,实测源体的磁场参数能达到高性能ECR离子源的设计要求.离子源采用较高频率的14.5 GHz微波馈入加热等离子体,波导直接馈入离子源以增强馈入微波的稳定性与效率.此外,还大量采用了一些有利于提高离子源高电荷态离子产额的关键技术,如铝内衬等离子体弧腔、负偏压盘、铝制等离子体电极、三电极引出系统、辅助掺气等.     

Hefei utility negative ions test equipment with RF source: commissioning and first results

In order to study the key technology and physics of RF driven negative ion source for neutral beam injector in China, the Hefei utility negative ions test equipment with RF source was developed at Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). Its negative ion source can be equipped with single or double RF drivers. There is a plasma expansion chamber with depth of 19 mm and an enhanced filter field. A three electrodes negative ion accelerator was employed to extract and accelerate the negative ions, which are plasma grid, extraction grid and ground grid. And there are several diagnostic tools for the plasma and beam parameters measurement. The characteristics of plasma generation, negative ion production and extraction were studied on the test equipment. The negative ion beam was extracted from the RF driven negative ion source for the first time. The detailed structure and main results are presented in this article.     

Discharge instability in a plasma contactor

Like the hollow cathode, discharge instability also occurs during the operation of a plasma contactor.Voltage and current probes were employed to test the change of keeper voltage, keeper current,anode voltage, and anode current parameters with time under different working conditions. The anode current range corresponding to the discharge instability phenomenon is about 0.4 A to 1.2 A,and the emission characteristic curve in this area appears to bulge wherein the four parameters all produce different degrees of oscillation, the anode current oscillation being the greatest. Its waveform is considered to consist of a small-amplitude, high-frequency triangular wave and a large-amplitude,low-frequency sawtooth wave, and we have explained the shape of the wave. Each parameter shows hundreds of Hz in oscillation frequency and the phases of the four parameters appear to be regular.After fast Fourier transform processing, the frequency and amplitude of the main peak of the anode current oscillation tend to change with changes of the anode current, and there are differences in the trends under different keeper currents and xenon flows.     

GeV/mA量级高功率圆形加速器中整数共振的抑制与利用

固定场交变梯度加速器（FFAG）是下一代GeV/mA量级高功率加速器的可能性方案,有潜力产生平均功率高达数个兆瓦的质子束。GeV量级等时性FFAG属于圆形加速器,目前主要面临整数共振穿越和高功率束流的高效率引出两个瓶颈问题。为了解决这两项瓶颈问题,本文提出了整数共振抑制器（IRS）的概念。IRS不仅对整数共振有显著的抑制作用,还可以利用整数共振激发可控的径向振荡,扩大引出圈间距,提高引出效率。以中国原子能科学研究院提出的等时性FFAG（CYCIAE-FFAG）方案为例,IRS不仅可有效抑制整数共振引起的束流包络增长（小于5%）,还可以用作引出圈间距优化（扩大至3 cm以上）。理论分析与数值模拟表明,基于IRS的设计方案有潜力成为下一代GeV/mA量级高功率圆形加速器的解决方案。     

Results of ICRF Heating Experiments from the EAST 2010 Campaign

Radio frequency(RF) plasma heating in ion cyclotron range of frequencies(ICRF)was successfully performed on the Experimental Advanced Superconducting Tokamak(EAST).This is mainly because lithium wall conditioning was routinely used to reduce both impurity and hydrogen(H) recycling and to improve the ICRF power absorption.Mainly ICRF heating of the H minority regime at 27 MHz has been applied in deuterium plasmas.The ion cyclotron resonance heating(ICRH) is found to depend strongly on plasma preheating.The ICRH efficiency can be much improved in conjunction with the lower hybrid wave(LHW).Effective ion and electron heating was observed with the H minority heating mode.The increase of the stored energy reached30 kJ in L-mode plasma by using the ICRF power of 1.0 MW alone when the H cyclotron resonance layer was at plasma center.