Ko Jinseok, Scott Steve, Levinton Fred, Galante Matthew, Sabbagh Steve, Hahn Sang-Hee, Jeon YoungMu
Korea Institute of Fusion Energy, Daejeon 34133, South Korea.
Commonwealth Fusion Systems, Cambridge, Massachusetts 02139, USA.
Rev Sci Instrum. 2021 Mar 1;92(3):033513. doi: 10.1063/5.0040823.
A polychrometer-type motional Stark effect (MSE) diagnostic technique, originally developed for the Alcator C-Mod tokamak, has been extended and applied to the Korea Superconducting Advanced Tokamak Research (KSTAR) device, the long-pulse superconducting tokamak, for the first time. It demonstrates a successful in situ subtraction of the polarized reflections off the vacuum vessel wall, sometimes up to half the total signal in some sightlines. To avoid the secondary neutral beam emission that may contaminate conventional beam-into-gas calibrations, a new approach, where the beam-into-gas measurements are made at various torus pressures with fixed vacuum fields, has been devised, which is possible with the stable superconducting coil systems of KSTAR. The validity of this new calibration scheme has been checked via plasma jog experiments. The experimental evidence of the polarized background light and the necessity of its correction in the MSE measurements made in KSTAR are presented as well.
一种最初为阿尔卡特C-Mod托卡马克开发的多色计型运动斯塔克效应（MSE）诊断技术，首次得到扩展并应用于长脉冲超导托卡马克——韩国超导先进托卡马克研究（KSTAR）装置。它成功地原位减去了来自真空容器壁的偏振反射，在某些视线方向上，这种反射有时高达总信号的一半。为避免可能污染传统束流进气体校准的二次中性束发射，已设计出一种新方法，即在固定真空场下于各种环面压力下进行束流进气体测量，这在KSTAR稳定的超导线圈系统中是可行的。通过等离子体慢跑实验检验了这种新校准方案的有效性。还给出了KSTAR中MSE测量中偏振背景光的实验证据及其校正的必要性。
