Dorris J R, Rost J C, Porkolab M
Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Rev Sci Instrum. 2009 Feb;80(2):023503. doi: 10.1063/1.3065094.
A novel rotating mask system has been designed and implemented on the DIII-D phase contrast imaging (PCI) diagnostic to produce the first spatially localized PCI measurements of a tokamak plasma. The localization technique makes use of the variation in the magnetic field component perpendicular to the viewing chord as a function of chord height. This new capability provides measurements in the range of 2<k<30 cm(-1), 10 kHz<f<10 MHz, and 0.7<r/a<1. This technique provides a spatial resolution of 10 cm at k=15 cm(-1) and can realistically provide measurements at a rate of 10 profiles/s. Calibration measurements show accurate characterization of the system transfer function making feasible a time dependent analysis that results in improved localization. Initial measurements show turbulence to peak near the plasma edge. This upgrade is part of a broader program to operate the DIII-D PCI at wave numbers up to 40 cm(-1) to probe electron scale turbulence in the plasma core.
一种新型旋转掩膜系统已在DIII-D相衬成像（PCI）诊断装置上设计并实现，用于对托卡马克等离子体进行首次空间局部化的PCI测量。该定位技术利用垂直于观测弦的磁场分量随弦高度的变化。这项新功能可在2<k<30 cm⁻¹、10 kHz<f<10 MHz和0.7<r/a<1的范围内进行测量。该技术在k = 15 cm⁻¹时提供10 cm的空间分辨率，并且实际能够以每秒10个剖面的速率进行测量。校准测量表明系统传递函数得到了准确表征，使得进行时间相关分析成为可能，从而改进了定位。初步测量显示湍流在等离子体边缘附近达到峰值。此次升级是一项更广泛计划的一部分，该计划旨在使DIII-D PCI在高达40 cm⁻¹的波数下运行，以探测等离子体核心中的电子尺度湍流。
