Measurement of Plasma Density and Magnetic Fluctuations using Microwave Reflectometers and Probes

(1)研制了一种新的诊断仪器——微波反射计，用于测量磁化等离子体中激发的静电和电磁波动。利用振动金属板对频率范围为8-18 GHz的反射计进行了校准，并将其设置在HITOP设备上。反射计测得的密度波动与朗缪尔探测器的观测结果吻合得很好。(2)研究了电子回旋共振产生的磁化等离子体中与径向电场相关的低频波动。当通过偏置分段端板控制径向电位分布时，观察到在正电场范围内长笛模式波动主要被激发，而在电场几乎为零的情况下，观察到漂移模式波动持续存在。随着径向电场强度的增加，漂移模式的波动趋于稳定。

(1) A new diagnostic, a microwave reflectometer, is developed in order to measure the electrostatic and electromagnetic fluctuations excited in a magnetized plasma. The reflectometer in the frequency range of 8-18 GHz has calibrated by using a vibrating metal plate and set at the HITOP device. The density fluctuations measured by the reflectometer agree well with that observed by Langmuir probes.(2) Low-Frequency fluctuations related with a radial electric field are investigated in a magnetized plasma produced by the electron cyclotron resonance. When the radial potential profile is controlled by biasing a segmented endplate, flute mode fluctuations are observed to be predominantly excited in a range of positive electric fields, while drift mode fluctuations are observed to persist in the case where the electric field is almost zero. The drift mode fluctuations are stabilized with an increase in the radial electric-field strength.