Titus J B, Griswold M E, Granstedt E M, Magee R M, Charkhesht N, Schroeder J H, Meekins M, Allfrey I
TAE Technologies, Inc., 19631 Pauling, Foothill Ranch, Lake Forest, California 92610, USA.
Rev Sci Instrum. 2022 Aug 1;93(8):083504. doi: 10.1063/5.0100498.
In TAE Technologies' current experimental device, C-2W (also called "Norman"), record-breaking, advanced beam-driven field-reversed configuration plasmas are produced and sustained in steady state utilizing variable energy neutral beams, advanced divertors, edge-biasing electrodes, and an active plasma control system [Gota et al., Nucl. Fusion 61, 106039 (2021)]. A novel diagnostic has been developed by TAE Technologies to leverage an industrial fiber Bragg grating (FBG) sensor array to detect heat flux along the wall of the vacuum vessel from a plasma discharge. The system consists of an optical fiber with FBG sensors distributed along its length, housed in a pressurized steel sheath. Each FBG sensor is constructed to reflect a different wavelength, the exact value of which is sensitive to the strain and temperature at the location of the grating in the fiber. The fiber is illuminated with broadband light, and the data acquisition system analyzes the spectrum of reflected light to determine the temperature at the location of each FBG. We have installed four of these vacuum-rated FBG sensor arrays on the C-2W experiment, each with 30 individual FBG sensors spaced at 0.15 m intervals along the 5 m fiber, with a 100 Hz acquisition rate. The measurement of temperature change due to a plasma discharge provides a single data point at each sensor location, creating a 120-point heat map of the vacuum vessel.
在TAE技术公司目前的实验装置C-2W（也称为“诺曼”）中，利用可变能量中性束、先进的偏滤器、边缘偏置电极和有源等离子体控制系统，产生并稳定维持了破纪录的先进束驱动场反转配置等离子体[戈塔等人，《核聚变》61, 106039 (2021)]。TAE技术公司开发了一种新型诊断方法，利用工业光纤布拉格光栅（FBG）传感器阵列来检测等离子体放电时沿真空容器壁的热通量。该系统由一根光纤组成，光纤上沿其长度分布着FBG传感器，封装在一个加压钢护套中。每个FBG传感器被设计用来反射不同的波长，其确切值对光纤中光栅位置处的应变和温度敏感。用宽带光照射光纤，数据采集系统分析反射光的光谱，以确定每个FBG位置处的温度。我们在C-2W实验中安装了四个这种真空额定的FBG传感器阵列，每个阵列有30个单独的FBG传感器，沿5米长的光纤以0.15米的间隔排列，采集速率为100赫兹。对等离子体放电引起的温度变化的测量在每个传感器位置提供一个数据点，从而创建真空容器的120点热图。
