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在先进实验超导托卡马克(experimental advanced superconducting Tokamak,EAST)装置上研制多道极向相关反射仪诊断,使系统可同时测量8(径向)×2(极向)个位置的电子密度涨落.该系统选用8个固定输出频率(12.5、13.5、14.5、15.0、15.5、16.0、17.0和18.0 GHz)的介质振荡器作为信号源,源输出的信号通过4倍频器倍频至V波段,通过多个3 d B定向耦合器耦合成一路,入射波通过一个20 d B定向耦合器分为2路,其中,主路微波通过一个角锥天线入射进入等离子体,副路微波作为参考信号.接收天线阵列由2个极向间隔为6 cm的角锥天线组成.参考信号和反射信号与频率为14.2 GHz的介质振荡器4倍频之后的输出信号进行混频,混频后的中频信号分别通过放大器、带通滤波器组件和同相正交解调器进行解调.通过该诊断系统,初步观察到了由低约束模式向高约束模式转换的现象,且在ELMfree阶段,台基梯度区域,出现了持续时间在毫秒量级、频率在40~50 k Hz的相干模.
In the advanced experimental superconducting Tokamak (EAST) device to develop a multi-polar correlation reflectometer diagnostic, so that the system can simultaneously measure the 8 (radial) × 2 (polar) position electron density up The system uses eight fixed-frequency (12.5,13.5,14.5,15.0,15.5,16.0,17.0 and 18.0 GHz) media oscillator as the signal source, the source output signal multiplied by the 4 frequency multiplier to the V band , Coupled through a plurality of 3 d B directional couple all the way into the incident wave through a 20 d B directional coupler is divided into 2, wherein the main road microwave through a pyramid antenna into the plasma, the sub-road microwave as a reference signal The receive antenna array consists of two pyramidal antennas spaced 6 cm apart and the reference and reflected signals are mixed with the output signal after multiplication by 4 times the frequency of 14.2 GHz dielectric oscillator. The mixed IF signal Respectively, through the amplifier, band-pass filter components and in-phase quadrature demodulator for demodulation.Through the diagnostic system, initially observed from the low constraint mode to high constraint mode conversion phenomenon, and in the ELMfree stage, the base gradient region, Now milliseconds in duration, frequency coherent mode of 40 ~ 50 k Hz.