Article title: A simulation study of a windowless gas stripping room in an E//B neutral particle analyzer

文章题目：E//B型中性粒子分析仪中无窗气体剥离室的模拟研究

DOI:10.1007/s41365-021-00909-8

One sentence summary:

一句话概要：

The performance of the neutral particle analyzer, a crucial diagnosis device in the potential nuclear fusion-based reactor, Tokamak, can be improved by constructing and optimizing a windowless gas stripping room.

中性粒子分析仪是托卡马克核聚变反应堆中的重要诊断设备，通过构造和优化无窗气体剥离室可以提高其性能。

http://www.nst.sinap.ac.cn/newsDetails/112/24750/en/

The Novelty (What)

This study constructed a windowless gas stripping room with two differential pipes in a neutral particle analyzer (NPA) with parallel electric and magnetic fields (E//B), a diagnosis device in Tokamak (toroidal device used in nuclear fusion research for magnetic confinement plasmas). The new design eliminated the replacement of stripping foils and eased the operation maintenance process. Moreover, multiple simulations, such as ANSYS Fluent, MolFlow+, and GEANT4, were applied to evaluate the design performance in terms of gas pressure distribution and stripping efficiency. It was identified that the optimum pressure for maximum global efficiency is 240 Pa. In the long run, the findings could improve the NPA diagnosis for the nuclear fusion study.

创新性（主要内容）

本研究在托卡马克装置（用于磁约束等离子体核聚变研究的环形装置）的诊断设备——具有平行电场和磁场（E//B）的中性粒子分析仪(NPA)中研制了一个具有两个差分管道的无窗气体剥离室。 这项新的设计省去了剥离膜的更换，简化了操作维护过程。 该研究利用ANSYS Fluent、MOLFLOW+、GEANT4等多种模拟软件，从气体压力分布和剥离效率两个方面对设计的剥离室性能进行了评价，得出获得最大综合效率的最佳气压为240 Pa。 从长远来看，这一研究结果可以改善核聚变研究中的NPA诊断。

The Background (Why)

研究背景（主要原因）

As a diagnosis device in the Tokamak, an NPA measures the charge exchange neutral particles escaping from plasma. Its functions include studying the energy distribution of fast ions and the isotopic ratio of the plasma. An NPA consists of a stripping unit that re-ionizes the neutral particles escaping from the Tokamak through charge exchange reactions. The stripping unit comprises stripping material in the form of either stripping foil or stripping gas. This study designs and simulates a windowless gas stripping room with two differential pipes in an E//B NPA to improve the device’s performance and maintenance, especially in terms of optimum pressure for maximum global efficiency. The simulation results would serve as a reliable reference for future practical applications.

NPA作为托卡马克装置中的诊断设备，测量从等离子体中发生电荷交换而逸出来的中性粒子。 它可用以研究等离子中的快离子能谱分布和同位素分布比例等。剥离单元是NPA的重要组成部分，通过电荷交换反应将从托卡马克中逸出来的中性粒子重新电离。 剥离单元的剥离介质通常有剥离膜和剥离气体两种。 这项研究为E//B NPA设计并模拟了具有两个差分管道的无窗气体剥离室，以改善装置的性能、简化装置的维护，特别是对剥离室获得最大综合效率的最佳气压进行了评估。 模拟结果可为今后的实际应用提供可靠的参考。

The SDG impact (Big Why)

At present, power plants generate electricity and energy through fossil fuels, nuclear fission, or renewable energy sources. A Tokamak is an experimental machine designed to harness the energy of nuclear fusion, potentially serving as an alternative to future energy generation. To turn such experimental design into reality, it is crucial for researchers to constantly explore new ways to improve and maintain the performance of the Tokamak facility. Therefore, the findings of this study contribute to the efforts of the understanding and the betterment of the device. It would eventually be beneficial to advance the future of energy production. (UNSDG 9: Industry, Innovation & Infrastructure)

SDG影响力（研究意义）

目前，发电厂主要通过化石燃料、核裂变，或可再生能源来发电。 托卡马克是实现核聚变能量利用的一种实验装置，有可能成为未来能源生产的替代方案。 要将这样的实验设计变为现实，关键是要不断探索新的方法来改善和保持托卡马克装置的性能。 因此，该研究有助于对该装置的理解和改进。 它最终将有利于推进未来能源的生产。 （联合国可持续发展目标9：工业、创新和基础设施）