Microwave Imaging Diagnostics in LHD

LHD 中的微波成像诊断

• 批准号: 14208055
• 负责人: NAGAYAMA Yoshio
• 金额: $ 32.2万
• 依托单位: National Institute for Fusion Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14208055/
• 关键词: LHD; Imaging; Reflectometrv; Micro-instability; microwave; MIR; plasma; turbulence; IMPAT発振器; ECE; ダイクロイックプレート; 画像計測; 核融合

A new diagnostic tool for the plasma density fluctuations measurements was developed at National Institute for Fusion Science. For the first time the Microwave, Imaging Reflectometer was deployed for plasma measurements at heliotron (stellarator) class of the thermonuclear fusion devices. Based on main LHD plasma parameters (magnetic field strength and electron plasma density) MIR system operates at 66,69GHz with extra-ordinary orientation of the launching microwave radiation. To deliver very broad Gaussian beam and to pick-up reflected radiation from precisely localized spatial regions inside plasma a very sophisticated Quasi-optical system with combination of high-sensitive detectors was installed. To extend the ability of the MIR system to operate with Electron Cyclotron Emission Imaging diagnostic special quasi-optical splitter (dichroic plate) was used. Both the MIR and ECEI techniques take advantage of large aperture optics to form an image of the reflecting/emitting layer onto a … More n array of detectors located at the image plane, enabling localized sampling of small plasma areas. To obtain the information on plasma fluctuations in poloidal, toroidal and radial directions a multiple antenna system was used.Low frequency plasma density oscillation (2-3 kHz) was observed during NBI plasma heating for regime with low plasma electron density. Some partial correlation (with correlation time 2.5 ms) was shown for poloidally separated detection channels. However, there was no clear evidence of the toroidal correlation in the reflected signals. From those data the estimated value Vθ=44 m/s of poloidal rotation velocity was obtained. During the experiments it was found that due to the very complicated 3-D shape of the plasma in the LHD device the issue of reflected beams focusing becomes of great importance. To improve the quasi-optical antenna system new elliptical antenna with variable steering angle is proposed. This will be giving a better flexibility to optimize the beam-line of the reflected radiation in order to achieve the maximum power of the reflected microwaves. Less

国家核聚变科学研究所开发了一种用于等离子体密度波动测量的新诊断工具，首次在基于 LHD 等离子体的热核聚变装置的日光管（仿星器）级中部署微波成像反射计进行等离子体测量。参数（磁场强度和电子等离子体密度）MIR 系统在 66,69GHz 下运行，具有非凡的发射微波辐射方向，可提供非常宽的高斯光束并精确拾取反射辐射。为了扩展中红外系统与电子回旋发射成像诊断一起运行的能力，安装了非常复杂的准光学系统和高灵敏度探测器，并使用了特殊的准光学分光器（二向色板）。 MIR 和 ECEI 技术都利用大孔径光学器件将反射/发射层的图像形成到位于图像平面的探测器阵列上，从而实现小型等离子体的局部采样为了获得有关极向、环形和径向方向的等离子体波动的信息，使用了多天线系统。在NBI等离子体加热过程中，在某些部分的低等离子体电子密度区域中观察到了低频等离子体密度振荡（2-3 kHz）。对于极向分离的检测通道显示出相关性（相关时间为 2.5 ms），但是，从这些数据中没有明显的证据表明反射信号中存在环形相关性。 m/s 的极向旋转速度在实验过程中发现，由于 LHD 装置中等离子体的 3-D 形状非常复杂，反射光束聚焦问题对于改善准光学变得非常重要。所获得的天线系统提出了一种具有可变转向角的新型椭圆天线，这将提供更好的灵活性来优化反射辐射的波束线，以实现反射微波的最大功率。

项目成果

Electron Cyclotron Emission Diagnostics for Helical Plasma in the Large Helical Device

大型螺旋装置中螺旋等离子体的电子回旋发射诊断

• 发表时间: 2004
• 作者: Y.Nagayama; K.Kawahata; S.Inagaki; T.Morisaki; K.Narihara
• 通讯作者: K.Narihara

Electron Cyclotron Emission Diagnostics in Large Helical Device

大型螺旋装置中的电子回旋发射诊断

• 发表时间: 2003
• 作者: Y.Nagayama; et al.
• 通讯作者: et al.

Electron Cyclotron Emission Diagnostics in Large Helical Device

大型螺旋装置中的电子回旋发射诊断

• 发表时间: 2003
• 作者: Y.Nagayama; et al.
• 通讯作者: et al.

Sawtooth Oscillation in Helical Plasma with Beam Driven Current in Large Helical Device

大型螺旋装置中束流驱动电流螺旋等离子体的锯齿振荡

• 发表时间: 2003
• 作者: Y.Nagayama; et al.
• 通讯作者: et al.

Electron Cyclotron Emission Diagnostics for Helical Plasma in the Large Helical Device

大型螺旋装置中螺旋等离子体的电子回旋发射诊断

• 发表时间: 2004
• 作者: Y.Nagayama; et al.
• 通讯作者: et al.