Establishment of Cross-Polarization Scattering Method for Measurement of Internal Magnetic-Field Fluctuations in Plasmas

1)在本研究项目期间，一个交叉极化散射诊断系统的频率为8-18 GHz的已被制作和应用到中心单元等离子体的伽马10串列镜，以测量内部磁场起伏。该系统利用双极化喇叭作为发射器和接收器，能够同时测量CPS和反射计，2）将CPS诊断系统和反射计应用于离子回旋频率范围（ICRF）和低频漂移波模式下的电磁等离子体波测量。通过对离子回旋加速器（ICRF）波的涨落进行观测，研究了RF加热功率的波吸收和Alfven离子回旋（AIC）不稳定性激发的物理机制。由端部损失通量和 ...更多信息 ii）随着等离子体β和温度各向异性的增加。AIC模式的振幅变大。出现了离散模态。相邻的MG模式耦合激发另一个低频波，导致等离子体β的饱和。iii）小波变换被施加到CPS和反射计信号的分析。小波时频谱和互相关函数使我们能够估计低频波的旋转速度（-3km/s）。s），以及AIC模式从中心向磁塞的传播速度（~ 1000 km/s）。iv）从散射波的角分布获得低频波（< 40 kHz）的k -ω谱。从k -Ω谱的脊线上首次证实了电磁漂移波的色散关系。4）对磁涨落产生的电磁波的CPS进行了计算研究。结果表明，模式转换波的光谱信号中的峰值频率由入射波、散射波和相对短波长的局部磁波动的磁波动之间的波数中的布拉格共振条件确定。少

1)During the period of this research project, a cross-polarization scattering diagnostic system with frequency of 8-18 GHz has been fabricated and applied to the central-cell plasma of the GAMMA 10 tandem mirror in order to measure internal magnetic-field fluctuations. The system utilized dual-polarized horns as a transmitter and a receiver that enabled the simultaneous measurement of the CPS and reflectometry, The density and magnetic fluctuations of the waves were evaluated from both the CPS and reflectometry.2)The CPS diagnostic system and reflectometer were applied to the measurement of electromagnetic plasma waves in the ion cyclotron range of frequencies (ICRF) and low-frequency drift-wave mode.i)The fluctuations associated with ICRF waves were observed to investigate the physics of the wave absorption of RF heating power and the excitation of an Alfven ion cyclotron (AIC) instability. The fluctuation-induced transport due to the AIC mode was evaluated from the end-loss flux and … More temperature of electrons during the excitation of the AIC mode.ii)As the plasma beta and temperature anisotropy increased. the amplitude of the AIC mode became large . and the discrete modes appeared. The adjacent MG modes coupled to excite another low-frequency wave that caused the saturation of the plasma beta.iii)The wavelet transform was applied to the analyses of the CPS and reflectometry signals. The wavelet time-frequency spectrum and cross-correlation function allowed us to estimate the rotation speed of the low-frequency waves (-3 km./s) in the ExB direction, and the propagation speed (-1000 km/s) of the AIC modes from the center towards the magnetic plugs.iv)The k -omega) spectra of the low-frequency wave (< 40 kHz) were obtained from the angular distribution of the scattered waves. From the ridge of the k -omega spectra the.dispersion relation of the electromagnetic drift wave was confirmed for the first time.4)Computational study on the CPS of electromagnetic waves produced by magnetic fluctuations was performed. It was shown that the peak frequencies in the spectral signals of the mode-converted waves were determined from the Bragg resonance condition in the wave number between the incident wave, scattered wave, and magnetic fluctuations for relatively short-wavelength localized magnetic fluctuations. Less