大型螺旋装置中用于微波成像反射测量的四种不同频率的同步投影与检测系统

Simultaneous projection and detection system of four different frequencies for microwave imaging reflectometry in Large Helical Device.

作者信息

Yoshinaga T, Nagayama Y, Kuwahara D, Tsuchiya H, Yamaguchi S, Kogi Y, Tsuji-Iio S, Mase A

机构信息

National Institute for Fusion Science, 322-6 Oroshi, Toki 509-5292, Japan.

出版信息

Rev Sci Instrum. 2010 Oct;81(10):10D915. doi: 10.1063/1.3491197.

DOI:10.1063/1.3491197

PMID:21033947

Abstract

A simultaneous projection/detection system of four different frequencies for microwave imaging reflectometry (MIR) was developed for three-dimensional observation of electron density fluctuations in the Large Helical Device (LHD). The microwave with four frequency components at 60.410, 61.808, 63.008, and 64.610 GHz is projected in a continuous-wave mode to illuminate the target LHD plasma. A two-dimensional horn-antenna mixer array (2D HMA) receives the reflected wave from the plasma as well as the wave from the local oscillator operating at 55.800 GHz. The first intermediate frequency (IF) signals at 4.610, 6.008, 7.208, and 8.810 GHz were confirmed to be obtained by downconversion of these microwaves using the 2D HMA. Each of these first IF components is filtered from each other and downconverted again for the superheterodyne detection. It was confirmed that both the amplitudes and the phases of the detected signals reflect the fluctuations in LHD plasmas.

摘要

为了对大型螺旋装置（LHD）中的电子密度涨落进行三维观测，开发了一种用于微波成像反射测量（MIR）的同时投影/检测系统，该系统具有四种不同频率。频率分别为60.410、61.808、63.008和64.610 GHz的四个微波分量以连续波模式投射，以照射目标LHD等离子体。二维喇叭天线混频器阵列（2D HMA）接收来自等离子体的反射波以及来自工作频率为55.800 GHz的本地振荡器的波。通过使用2D HMA对这些微波进行下变频，确认获得了频率为4.610、6.008、7.208和8.810 GHz的第一中频（IF）信号。这些第一中频分量中的每一个都相互滤波，并再次进行下变频以进行超外差检测。已确认检测信号的幅度和相位均反映了LHD等离子体中的涨落。