基于电感耦合等离子体源的CO2色散干涉仪搭建和测试

在电感耦合等离子体源(ICP)装置上成功地搭建了一套没有减震系统的水平单道测量的CO₂色散干涉仪,用以测量等离子体的弦积分电子密度,并且与HCN干涉仪结果作对比,证明了CO₂色散干涉仪的可行性。     

HL-2M 装置 CO2 色散干涉仪研制

研制了一套新型 CO₂ 激光色散干涉仪用于 HL-2M 装置初始放电期间的电子密度测量。该系统采用 基于激光倍频的色散测量原理,能够消除机械振动产生的相位误差。该系统使用全新的调相式信号调制,研发了 相应的数据采集/处理/上传系统。根据实验测量结果表明,CO₂ 激光色散干涉仪和微波干涉仪测量曲线基本一致, 色散干涉仪系统的测量精度约为 2×10¹⁷m⁻³,密度测量上限能达到 10²¹m⁻³。     

易于数字化处理等离子体密度的微波干涉仪

一、引言 用微波干涉仪测量等离子体电子密度是一种常用的诊断手段,但通常不易于数字化,并且精度也不高。本文描述了用阶梯波调制的微波干涉仪原理,提出了用计算机直接处理干涉信号的方法,并实际测得了密度曲线。实验结果表明:这种干涉仪的原理及处理方法对于稳态长脉冲等离子体实验装置的密度测量是可行的。测量的相移量容易达到π/10。并且不需增加任何电子线路和微波器件。     

转镜调制二氧化碳激光干涉仪

耦合腔干涉仪是在激光器出现后才发展起来的新型干涉仪。由于其光路简单,易于调整,对等离子体无干扰等优点,已成为稠密等离子体密度测量的常用工具。如所周知,耦合腔激光干涉仪对等离子体电子密度测量的灵敏度为:     

HL-2A装置偏滤器中的微波干涉仪测量

微波干涉仪测量等离子体电子密度是一种常规监测工具，利用这种工具可以给出电子密度随时间变化的波形图。等离子体电子密度和微波干涉仪测出的相位差之间的关系为：     

剪切干涉测量电缆枪等离子体电子密度

用剪切干涉仪测量了电缆枪产生的等离子体电子密度分布.在实验中获得了激光波前通过等离子体后的干涉图样,测出等离子体沿轴向的平均运动速度约为2 cm/μs.对干涉图进行了二维波前重建,计算了电子线积分密度,给出了直观的等离子体分布图像,并计算了自由电子总数.根据等离子体的圆柱对称关系,利用Abel积分变换算出了局部电子密度沿径向的分布曲线.     

HL—1M装置电子密度测量及密度峰化分布研究

描述了ＨＯ－１Ｍ装置建造的远红外激光干涉仪系统，以及用该系统进行的等离子体电子密度分布测量。密度数据的采集与处理采用了计算机Ｗｉｎｄｏｗｓ界面，提高了采集效率和速度。     

HL-2M 装置固态亚毫米波干涉系统研制

发展了一套固态亚毫米波外差干涉系统和一种基于全相位快速傅里叶变换(apFFT)的相位处理方法用 于测量 HL-2M 初始等离子体电子密度。该系统采用平面型二极管倍频技术对低频的锁相微波源进行高次倍频以 产生功率大于 0.1MW、频率 306.9GHz 的探测波。基于 apFFT 的相位处理数值算法可以从原始信号中提取相位信 息,缓解由可能的高水平密度扰动导致的相位跳变。系统的固有时间分辨率为 5μs,电子密度测量范围在 10¹⁶~10²⁰m⁻³。在 HL-2M 装置首次实验期间,该系统被安装在中平面上,利用装置内壁反射实现干涉测量,成功 测量了线平均电子密度。      

多道HCN激光干涉仪在HL—1装置上的电子密度分布测量

本文描述了为测量ＨＬ－１装置电子密度分布而研制的多道远红外激光干涉仪系统及其特点，首次对装置在弹丸加料以及拉瓦尔超声分子束注入实验条件下的等离子体电子密度时－空分布进行了观测和初步分析，同时，介绍一种处理密度相移信号的新方法。     

干涉法诊断由纳秒激光诱导产生的大气等离子体的电子密度

通过改进的马赫-曾德尔干涉仪获得了高质量的Nd:YAG激光诱导大气等离子体干涉条纹图.利用快速傅里叶变换（FFT）分析法恢复了干涉图波面,通过Abel逆变换进行密度反演,重建了不同时刻激光等离子体电子密度的三维分布,并得到了激光等离子体膨胀速度与延迟时间的关系.结果显示,纳秒激光诱导大气击穿形成的等离子体具有等离子体通道结构,等离子体膨胀速度的迅速衰减,对等离子体通道的塌陷起到了促进作用,等离子体形状的离心率在大约48 ns时达到最大值,然后开始向圆形演变. 关键词： 激光等离子体电子密度 干涉测量 Abel逆变换     

七道远红外HCN激光干涉仪的数据处理和实验结果

本文用非对称Abel变换,研制了一套计算机程序,对七道远红外HCN激光干涉仪测量的信号进行数据处理,并在HT-6M托卡马克中获得了等离子体电子密度时空分布的实验结果。     

Determination of some transport properties of argon from transient arc behaviour

A new method is described which enables the electrical conductivity and electron mobility to be derived from the measurement of either the decay, following interruption, or response of a wall stabilized arc to a step change in current. This has been achieved by using a laser interferometer to record the corresponding change in electron density. The method has been applied to arcs of different radii and the derived transport properties are given in the range 8,800–12,200 °K for argon at atmospheric pressure.     

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A three-channel far-infrared (FIR) HCN laser interferometer has been developed to measure the line averaged electron density on EAST tokamak. Detectors with the properties of high sensitivity, high signal-to-noise ratio, small volume and stability are needed in interferometer device. The application of new Schottky barrier diode (SBD) detector has made the density signal and the signal-to-noise ratio greatly improved. The disturbance caused by the lower hybrid wave can be eliminated by using double copper foil shield and narrow band pass filter. The improved detectors have worked well during the long pulse discharge and H mode discharge.     

A Fast Interferometer Using a Nitrogen Laser for Dense Plasmas

A Mach-Zehnder interferometer utilizing a short pulse (5 ns FWHM) nitrogen laser has been built and successfully operated. This system is capable of measuring plasma electron densities higher than 1020 cm-3 and is simple as well as inexpensive. The same system can be used for schlieren and shadow photography. Examples of an interferogram and a shadowgraph of a high density plasma are presented.     

New data processing for multichannel FIR laser interferometer

Usually, both the probing and reference signals received by LATGS detectors of FIR interferometer pass through hardware phase discriminator and the output phase difference--hence the electron line densities is collected for analysis and display with a computerized data acquisition system(DAS). In this paper, a new numerical method for computing the phase difference in software has been developed instead of hardware phase discriminator, the temporal resolution and stability is improved. An asymmetrical Abel inversion is applied to processing the data from a seven-channel FIR HCN laser interferometer and the space-time distributions of plasma electron density in the HT-6M tokamak are derived.     

利用x射线激光干涉诊断等离子体电子密度

x射线激光探针干涉方法是诊断高温高密度激光等离子体电子密度等信息的重要工具.利用神光Ⅱ装置输出激光驱动的类镍-银x射线激光作为探针，成功地进行了马赫-曾德尔干涉法诊断实验，获得了清晰的包含等离子体信息的动态干涉条纹图像，并据此给出了待测C8H8等离子体临界面附近电子密度的空间分布. 关键词： 等离子体电子密度诊断 x射线激光 马赫-曾德尔干涉仪     

Multi-Channel FIR HCN Laser Interferometer on HT-7 Tokamak

A Five-channel far-infrared (FIR) hydrogen cyanide (HCN) laser interferometer was developed to measure plasma electron density profile on the HT-7 superconducting tokamak. The structure of the five-channel FIR laser interferometer is described. The laser source used in the interferometer was a continuous wave glow discharge HCN laser with 3.4 m cavity length and 100 mW power output at 337 m wavelength. The temporal resolution was 0.1 ms and the detection sensitivity was 1/12 fringe. Preliminary experimental results measured by the interferometer on HT-7 tokamak are reported.     

Development of a two-color interferometer for observing wide range electron density profiles with a femtosecond time resolution

A two-color interferometer for preformed plasma characterization is developed. We observe the electron density distribution of preformed plasmas on a 5 μm-thick copper target irradiated with a high-intensity Ti:sapphire laser. The two-color interferometer extended the observable electron density region using a fundamental (800 nm) probe beam to cover the lower density region and a second harmonic (400 nm) probe beam to cover the higher density region, simultaneously. This characterization of the electron density distribution of preformed plasmas with femtosecond time resolution significantly contributes to the understanding of high-intensity laser–thin-foil interactions during high-energy electron, ion, and X-ray generation. PACS 52.38.-r; 52.50.Jm; 52.70.-m     

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利用多道远红外HCN激光干涉仪实时测量了等离子体中的粒子数增量,首次得到了HL-2A等离子体偏滤器位形和孔栏位形下强场侧和弱场侧SMBI的加料效率,结果与法国Tore Supra装置的SMBI加料效率的范围相一致。     

Two-dimensional interferogram of an exploding selenium foil using asoft X-ray laser interferometer

We have developed a soft X-ray interferometer capable of probing large high-density plasmas with micron spatial resolutions. A neon-like yttrium X-ray laser operating at 155 Å was combined with the Mach-Zehnder interferometer to obtain electron density profiles of a laser-produced exploding selenium foil plasma. The plasma was produced with one Nova laser beam using a 120-μm line focus, the same conditions used to create a selenium X-ray laser. The interferogram of the selenium plasma was obtained from an end-on perspective