Yatsuka Eiichi, Kinjo Kiyotake, Morikawa Junji, Ogawa Yuichi
Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8568, Japan.
Rev Sci Instrum. 2009 Feb;80(2):023505. doi: 10.1063/1.3082047.
To identify the mode-converted electron Bernstein wave (EBW) in a torus plasma directly, we have developed an interferometry system, in which a diagnostic microwave injected outside of the plasma column was directly detected with the probing antenna inserted into the plasma. In this work, plasma production and heating are achieved with 2.45 GHz, 2.5 kW electron cyclotron heating (ECH), whereas diagnostics are carried out with a lower power (10 W) separate frequency (1-2.1 GHz) microwave. Three components, i.e., two electromagnetic (toroidal and poloidal directions) and an electrostatic (if refractive index is sufficiently higher than unity, it corresponds to radial component), of ECRF electric field are simultaneously measured with three probing antennas, which are inserted into plasma. Selectivities of each component signal were checked experimentally. Excitation antennas have quite high selectivity of direction of linear polarization. As probing antennas for detecting electromagnetic components, we employed a monopole antenna with a length of 35 mm, and the separation of the poloidal (O-wave) and toroidal (X-wave) components of ECRF electric field could be available with this antenna. To detect EBW, which is an electrostatic wave, a small tip (1 mm) antenna was used. As the preliminary results, we detected signals that have three characteristics of EBW, i.e., short wavelength, backward propagation, and electrostatic.
为了直接识别托卡马克等离子体中的模式转换电子伯恩斯坦波（EBW），我们开发了一种干涉测量系统，在该系统中，注入等离子体柱外部的诊断微波通过插入等离子体中的探测天线直接进行检测。在这项工作中，等离子体的产生和加热通过2.45 GHz、2.5 kW的电子回旋加热（ECH）实现，而诊断则使用较低功率（10 W）的单独频率（1 - 2.1 GHz）微波进行。通过插入等离子体的三个探测天线同时测量电子回旋共振加热（ECRF）电场的三个分量，即两个电磁分量（环形和极向方向）和一个静电分量（如果折射率足够高于1，则对应于径向分量）。对每个分量信号的选择性进行了实验检验。激励天线对线偏振方向具有相当高的选择性。作为检测电磁分量的探测天线，我们使用了长度为35 mm的单极天线，利用该天线可以分辨ECRF电场的极向（O波）和环形（X波）分量。为了检测作为静电波的EBW，使用了一个小尖端（1 mm）天线。作为初步结果，我们检测到了具有EBW三个特征的信号，即短波长、反向传播和静电特性。
