Development of the Q-band ECE imaging system in the large helical device
Development of the Q-band ECE imaging system in the large helical device
复制标题
大型螺旋装置Q波段ECE成像系统的研制
DOI：
10.1088/1748-0221/17/01/c01016
复制
发表时间：
2022
影响因子：
1.3
通讯作者：
Yamada I.
中科院分区：
文献类型：
--
作者：
Goto Y.;Tokuzawa T.;Kuwahara D.;Ichinose K.;Tsuchiya H.;Nishiura M.;Shimizu T.;Kubo S.;Yamada I.
在这项研究中，我们开发了大型螺旋装置(LHD)中Q波段的电子回旋发射成像(ECEI)系统。ECEI测量使获得高β等离子体中磁流体不稳定性的时空结构成为可能。虽然实现多信道化还存在一些困难，如本地振荡器(LO)光学器件和昂贵的高功率LO源，但我们已经解决了这些问题，我们开发了一种具有内部LO电源的本地集成天线阵列(LIA)，在每个通道上使用倍频集成电路，而不是传统的具有普通LO的喇叭天线混频阵列(HMA)。此外，我们还做了一些改进，以提高测量信号的质量。首先，我们开发并引入了陷波滤波器，以防止强电子回旋共振加热(ECRH)杂散信号混入测量电路。其次，重新考虑了内置在印刷电路板中的倍增器的位置，以防止高次谐波分量混合到混音器中。此外，我们还采用了对数探测器(LOG探测器)来处理宽动态范围的等离子体起伏。经过这些改进，首次成功地得到了铲运机内部二维温度分布及其涨落分布的初步结果。
In this study, we developed the Electron Cyclotron Emission Imaging (ECEI) system with the Q-band in the Large Helical Device (LHD). ECEI measurement makes it possible to obtain the spatiotemporal structure of magnetohydrodynamics (MHD) instabilities in the high-β plasma. Although there were several difficulties for realizing the multi-channelization, such as local oscillator (LO) optics and an expensive high-power LO source, we have solved these problems by developing a Local Integrated Antenna array (LIA) which has an internal LO supply, using a frequency doubler integrated circuit on each channel, instead of a conventional Horn-antenna Mixer Array (HMA) with common LOs. In addition, we have made some improvements to enhance the quality of the measurement signal. First, we developed and introduced notch filters that prevent the strong Electron Cyclotron Resonance Heating (ECRH) stray signal from being mixed into the measurement circuit. Second, the position of the doubler built in the printed circuit board was reconsidered to prevent the mixing of higher harmonic components into the mixer. Also, we have adopted the Logarithmic detector (LOG detector) to deal with the wide dynamic range of the plasma fluctuation. After these improvements, for the first time, we could successfully obtain the initial results of the two-dimensional temperature distribution and its fluctuation distribution in the LHD.