Moon Chanho, Yamasaki Kotaro, Nagashima Yoshihiko, Inagaki Shigeru, Ido Takeshi, Yamada Takuma, Kasuya Naohiro, Kosuga Yusuke, Sasaki Makoto, Kawachi Yuichi, Nishimura Daiki, Kobayashi Taiki, Fujisawa Akihide
Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Koen, Kasuga-City, Fukuoka, 816-8580, Japan.
Department of Mechanical Engineering, Graduate School of Engineering, Hiroshima University, Higashihiroshima, Hiroshima, 739-8527, Japan.
Sci Rep. 2021 Feb 19;11(1):3720. doi: 10.1038/s41598-021-83191-3.
A tomography system is installed as one of the diagnostics of new age to examine the three-dimensional characteristics of structure and dynamics including fluctuations of a linear magnetized helicon plasma. The system is composed of three sets of tomography components located at different axial positions. Each tomography component can measure the two-dimensional emission profile over the entire cross-section of plasma at different axial positions in a sufficient temporal scale to detect the fluctuations. The four-dimensional measurement including time and space successfully obtains the following three results that have never been found without three-dimensional measurement: (1) in the production phase, the plasma front propagates from the antenna toward the end plate with an ion acoustic velocity. (2) In the steady state, the plasma emission profile is inhomogeneous, and decreases along the axial direction in the presence of the azimuthal asymmetry. Furthermore, (3) in the steady state, the fluctuations should originate from a particular axial position located downward from the helicon antenna.
作为新时代的诊断手段之一，安装了一台断层扫描系统，用于检测线性磁化螺旋波等离子体的结构和动力学的三维特征，包括其涨落。该系统由位于不同轴向位置的三组断层扫描组件组成。每个断层扫描组件能够在足够的时间尺度上测量等离子体在不同轴向位置的整个横截面上的二维发射轮廓，以检测涨落。包括时间和空间的四维测量成功获得了以下三个在没有三维测量时从未发现的结果：（1）在产生阶段，等离子体前沿以离子声速从天线向端板传播。（2）在稳态下，等离子体发射轮廓是不均匀的，并且在存在方位不对称的情况下沿轴向减小。此外，（3）在稳态下，涨落应起源于螺旋波天线下方的特定轴向位置。
