摘要
本文介绍了在HL-2A装置上发展的多道微波干涉系统,该系统采用单边带频率调制技术和微波有源倍频驱动技术,实现了对等离子体电子密度的超外差测量。系统有四个测量通道,对应测量弦位置分别为r=5,11,18,24 cm,可在96.7~110 GHz范围内任一固定频率点工作,最大可测电子密度取决于设定的工作频率,最小可测量电子密度为1.05*10~(14)m~(-3)。系统最大的优点是可以同时实现等离子体电子密度分布测量和电子密度扰动测量。在HL-2A物理实验中,利用这套系统获得了与激光干涉和微波反射测量的结果具有很好一致性的电子密度分布;并对锯齿先兆以及高频反剪切阿尔芬本征模(RSAE)进行了初步研究.
A multi-channel microwave interferometer system for the line-averaged density and density fluctuation measurements has been developed on the HL-2A tokomak.The system consists of a microwave synthesizer,a single side band(SSB) mixer,a frequency multiplier,a frequency downconverter system and a quadrature system,that enable super-heterodyne measurement.This system has one launcher and four receivers,which located in r=5,11,18,and 24 cm,respectively.The working frequency varies from 96.7 GHz to llOGHz.The measured line-averaged densities agree well with that measured by FIR interferometer.The reconstructed density profile is in substantial agreement with that measured by FMCW reflectometer.Finally,the saw-tooth precursor and high frequency RSAE with down-chirping behavior observed by the system demonstrates the features:high temporal resolution and high frequency response,respectively.
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