J-TEXT相关电子回旋辐射测量系统的研制

Development of correlation electron cyclotron emission system on J-TEXT

为了更好地研究反常输运,J-TEXT发展了一套相关电子回旋辐射(CECE)系统来测量电子温度涨落。该系统采用频率去相关的结构,通过八道窄带滤波器进行频率选择,其中两道采用带宽为100MHz的定频滤波器,其余六道采用带宽为100~240MHz的钇铁石榴石(YIG)滤波器,YIG滤波器的中心频率为数字可调,增加了系统的灵活性。通过光路的优化,系统的极向分辨率最高可达2.5cm-1。实验结果表明系统性能良好,通过互相关技术可以消除热噪声的影响得到电子温度涨落,并且观测到靠近等离子体芯部的电子温度涨落要小于靠近边缘的电子温度涨落。

To study anomalous transport, a correlation electron cyclotron emission(CECE) system has been developed on J-TEXT for electron temperature fluctuations measurement. The spectral decorrelation method is employed for the CECE system. Frequency selection is performed by eight narrow band filters, two of them are fixed frequency band-pass filters with bandwidth of 100 MHz, and the others are yttrium iron garnet(YIG) filters with bandwidth of 100~240 MHz. The YIG filters with center frequency adjustable make the CECE system more flexible. Optical optimization of the transmission line is used to achieve a poloidal resolution up to 2.5 cm^-1. The experimental results show good performance of the system. Cross-correlation analysis on the two adjacent channel separated by 200 MHz can eliminate the influence of the thermal noise and obtain the electron temperature fluctuations, moreover, the electron temperature fluctuations near the core of plasma less than that near the edge of the plasma is observed.