Development of Magnetic Field Distribution Measurement in a Plasma by Means of Beam Probe/Laser Spectroscopy

研究了一种利用粒子束注入和激光诱导荧光相结合的塞曼效应提高等离子体磁场分布测量精度的方法。然而，得出的结论是，激光诱导荧光的强度是不够的，以实现良好的时间和空间分辨率。然后，我们已经将我们的努力转移到那些利用运动斯塔克效应（MSE）的精度的提高。本文编制了一个计算H_2原子均方误差谱的程序<alpha>，该程序考虑了有关的原子过程、束流注入几何和观测视线等因素，计算结果准确、精确。被认为是在等离子体中的电离和电荷交换和电子密度依赖的激发的光束衰减。离子束源的结构、束流的发散度、托卡马克的磁结构、观测的持续角和托卡马克的狭缝函数 ...更多信息 从模拟程序中得到的结果如下：对于MSE诊断的最佳设计，1）对于离子源配置，纵横比为2的椭圆是最佳的，以及2）诊断束应该从垂直方向倾斜25度，并且应该从位于与束相距70度的环形角的端口观察。2）等离子体中的极向磁场可以由具有0、45、90 °偏振方向的4个线偏振器的同时测量来确定，3）利用由于束流有限发散而引起的谱线红移和蓝移π线之间的不对称性，确定了JFT-2 M托卡马克上加热中性束的发散角为1.3 °。

A technique of improving the accuracy of magnetic field distribution measurement in a plasma utilizing the Zeeman effect with a combination of the particle beam injection and laser induced fluorescence method was investigated. It is, however, concluded that the intensity of laser-induced fluorescence is not enough to achieve good time-and space-resolution. Then, we have shifted our effort to the improvement of the accuracy of those which utilize the Motional Stark Effect (MSE). A code has been developed to simulate the MSE spectrum of H_<alpha>, taking accurately and precisely into account the related atomic processes as well as geometries of the beam injection and observation line of sight. A beam attenuation by ionization and charge exchange in the plasma and an electron density dependence of the excitation are regarded. Configuration of the ion beam source, divergence of the beam, magnetic configuration of the tokamak, sustaining angle of the observation, and a slit function of the … More spectrometer are also taken into account.The results obtained from the simulation code are as follows :As for the optimum design of MSE diagnostics, 1) an ellipse of aspect ratio 2 is optimum for the ion source configuration, and 2) the diagnostic beam should be tilted by 25 degrees from the perpendicular direction, and should be observed from a port located at the toroidal angle of 70 degrees apart from the beam.As applications of the MSE spectral calculation, it has been shown that 1) it will be possible to obtain the electron density from the MSE spectrum, 2) poloidal magnetic field in a plasma can be determined from a simultaneous measurement with 4 linear polarizers having the polarization direction of 0,45,90, and 135 degrees with respect to the horizontal direction, and 3) utilizing the fact that the spectrum shows an asymmetry between red-shifted pi line and blue-shifted one due to the finite divergence of the beam, a divergence angle of 1.3 deg.of the heating neutral beam on the JFT-2M tokamak at JAERI was determined Less