Neutron Spectroscopy of Deuterium-deuterium Reactions in Neutral Beam-heated Plasmas on the Large Helical Device

IF 2.3 4区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Journal of Fusion Energy Pub Date : 2026-03-13 DOI:10.1007/s10894-026-00564-0

Siriyaporn Sangaroon, Kunihiro Ogawa, Longyong Liao, Guoqiang Zhong, Mitsutaka Isobe

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Abstract

The compact neutron emission spectrometers (CNES) system has enabled detailed and comprehensive characterization of fast ion confinement during the neutral beam injection heating in the Large Helical Device (LHD). Using high resolution neutron spectroscopy along both tangential and perpendicular lines-of-sight, CNES provides direct experimental access to deuterium–deuterium (D–D) reaction dynamics in velocity space, reflecting the behavior of fast ions injected by neutral beam injections. Significant Doppler shifts in D-D neutron energy were observed during intense tangential neutral beam injection, revealing the impact of the relative motion of the D-D reaction center-of-mass (CoM) with respect to the CNES sightline. An upshift in neutron energy was detected when the CoM moved toward the sightline, while a downshift occurred when it move away from the sighline. In plasmas heated by perpendicular neutral beam injection, a distinct double-humped neutron energy spectrum was observed, corresponding to the Larmor motion of helically trapped beam ions within the LHD’s magnetic ripple structure. The results demonstrate the capability of CNES to detect Doppler shifts in neutron energy associated with the direction and confinement of fast ions. By comparing experimental results with numerical simulations, the study confirms the reliability of both tangential and perpendicular CNESs sightline configuration in D-D neutron emission spectroscopy in LHD. The results improve our understanding of how fast ions generated by neutral beam injection affect D-D reaction.

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大型螺旋装置上中性束加热等离子体中氘-氘反应的中子光谱

紧凑中子发射光谱仪（CNES）系统能够详细和全面地表征大螺旋装置（LHD）中性束注入加热过程中的快离子约束。CNES利用沿切向和垂直视线的高分辨率中子光谱学，提供了在速度空间中直接实验氘-氘（D-D）反应动力学的途径，反映了中性束注入的快离子的行为。在强切向中性束注入过程中观察到D-D中子能量的显著多普勒频移，揭示了D-D反应质心（CoM）相对于CNES视线的相对运动的影响。当质心向视线移动时，检测到中子能量上升，而当质心远离视线时，中子能量下降。在垂直中性束注入加热的等离子体中，观察到明显的双驼峰中子能谱，对应于LHD磁纹波结构中螺旋俘获束离子的拉莫尔运动。结果表明，CNES能够探测到与快离子方向和约束有关的中子能量的多普勒频移。将实验结果与数值模拟结果进行比较，证实了LHD中D-D中子发射光谱中切向和垂直CNESs视线配置的可靠性。结果提高了我们对中性束注入产生的快速离子如何影响D-D反应的理解。

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来源期刊

Journal of Fusion Energy 工程技术-核科学技术

CiteScore

2.20

自引率

0.00%

发文量

审稿时长

2.3 months

期刊介绍： The Journal of Fusion Energy features original research contributions and review papers examining and the development and enhancing the knowledge base of thermonuclear fusion as a potential power source. It is designed to serve as a journal of record for the publication of original research results in fundamental and applied physics, applied science and technological development. The journal publishes qualified papers based on peer reviews. This journal also provides a forum for discussing broader policies and strategies that have played, and will continue to play, a crucial role in fusion programs. In keeping with this theme, readers will find articles covering an array of important matters concerning strategy and program direction.