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一、引 言 微波法测量等离子体的电子密度通常采用 Wharton-Gardner条纹干涉仪,这种经典的条纹干涉仪对于大截面高密度的瞬变等离子体所产生的数十个2π相移变化特别是电子密度之空间分布的测量有一定的局限性。当相移超过10个2π弧度时,在示波器上读取这种干涉仪的条纹移动是很困难的。而大相移直读式微波相位测量系统能把瞬变等离子体引起的微波相移的2π弧度的数目转换成电脉冲。这些对应于密度上升和下降的2π弧度相移量的脉冲经过适当处理,既可供直读也可供计算机进行数据处理。目前该系统每500微秒可分辨2π弧度的相移。同时,它还可以利用波导桥网络的检波输出在示波器上观测条纹的移动,以便进行监测。所以它对于大型或中型托卡马克装置的测量是比较适合的。
I. INTRODUCTION The electron density of microwaves is usually measured by the Wharton-Gardner stripe interferometer. The classic stripe interferometer has many dozens of 2π phase-shift changes in large-area and high-density transient plasmas, especially the electron Density of the spatial distribution of the measurement has some limitations. When the phase shift exceeds 10 2π radians, it is difficult to read the stripe movement of this interferometer on the oscilloscope. The large phase shift direct reading microwave phase measurement system can transform the number of 2π radians caused by transient plasma microwave phase shift into electrical pulses. These pulses, corresponding to a 2π radian phase shift between rising and falling densities, are properly processed for both direct reading and computerized data processing. The system currently resolves 2π radians of phase shift every 500 microseconds. At the same time, it can also observe the movement of streaks on the oscilloscope with the detection output of the waveguide bridge network for monitoring purposes. So it is more suitable for the measurement of large or medium tokamak devices.