EAST中性束穿透损失分析

Analysis of shine-through of EAST neutral beam

中性束注入(NBI)是托卡马克装置四种辅助加热手段(中性束注入、低杂波、离子回旋段波、电子回旋段波)中加热效率最高、物理机制最清楚的一种等离子体加热技术,是国际聚变界公认的最有效的辅助加热手段之一。为了探究EAST-NBI的穿透损失,通过对穿透损失率产生原理的理论分析,设计了具体硬件电路框图和实验方案,并通过实验验证了理论推导的正确性。具体做法首先通过对离子源束斑内中心点热电偶进行定量标定的方法作为穿透损失计算的标准。通过石墨瓦上热电偶单位能量下的温升与标定热电偶的温升之比来对穿透损失率进行计算。实验结果表明在一定的束能范围内,穿透损失率随着注入束能的增加而线性增长,穿透损失率随着等离子体密度增长呈指数衰减。

High-energy neutral beam injection（NBI） is one of the four Tokamak auxiliary heating methods（The four meth-ods are the neutral beam injection, lower hybrid, ion cyclotron waves paragraph, and the section electron cyclotron waves）. Due tothe highest heating efficiency, and the clearly physical mechanism, NBI is regarded as the most effective heating method by international fusion community. In order to explore shine through of EAST（Experimental Advanced Superconducting Tokamak）-NBI,specific hardware circuit block diagram and experimental scheme are designed based on the theoretical analysis of the principle ofshine through, and the correctness of the theoretical deduction is verified by experiments. The method of quantitative calibrationof the thermocouple in the center point of the ion source beam spot is the standard for the calculation of the shine through. Thevalue of shine-through is calculated by the ratio of the armor tile thermocouple unit energy of temperature rise to that of calibratedone. The experimental results show that, in a certain range, the shine through increases linearly with the increase of the injectionbeam energy, and decreases exponentially with the increase of the plasma density.