Beam emission spectroscopy measurement for density fluctuations in compact helical system
Beam emission spectroscopy measurement for density fluctuations in compact helical system
复制标题
紧凑螺旋系统中密度波动的束发射光谱测量
DOI：
10.1063/1.1794846
复制
发表时间：
2004
影响因子：
1.6
通讯作者：
S. Okamura
中科院分区：
文献类型：
--
作者：
T. Oishi;S. Tanaka;S. Kado;M. Yoshinuma;K. Ida;S. Okamura
光束发射光谱（BES）系统被提出作为测量长波长等离子体密度波动的方法，已应用于紧凑螺旋系统（CHS）。 BES 的空间通道由 16 根光纤组成，物镜聚焦在 CHS 中的等离子体短半径上。与成像表面上的视线宽度和视线之间的空间间距相对应的空间分辨率分别为1.0和1.1cm。探测束使用加速电压约为28keV的加热用氢中性束。雪崩光电二极管探测器与 100kHz 低通滤波器相结合用作光子探测器。在光束衰减可忽略不计的边缘区域同时测量逆密度尺度长度 Ln−1 的时间演化和密度涨落。初步结果是，等离子体边缘附近的局部等离子体密度梯度迅速增加，并伴随着类似相干的密度涨落……
A system of beam emission spectroscopy (BES) which has been proposed as a method for the measurement of long wavelength plasma density fluctuations has been applied to compact helical system (CHS). Spatial channels of BES consist of 16 optical fibers with object lenses focused on the plasma minor radius in CHS. Spatial resolution which corresponds to the width of a sightline and the spatial pitch between sightlines are 1.0 and 1.1 cm on the imaging surface, respectively. The hydrogen neutral beam for heating with the acceleration voltage of about 28 keV is used for the probe beam. The avalanche photodiode detectors combined with a 100 kHz low-pass filter are used as photon detectors. The temporal evolution of the inverse density scale length Ln−1 and the density fluctuation were measured simultaneously at the edge region where the beam attenuation was negligible. As an initial result, the rapid increase of the local plasma density gradient near the plasma edge accompanied by a coherent-like density fluctu...