Assessment of magnetic smearing effects for the MAST-U beam emission spectroscopy system

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Fusion Engineering and Design Pub Date : 2025-04-26 DOI:10.1016/j.fusengdes.2025.115075

P. Balazs , O. Asztalos , M.S. Fonyi , S. Thomas , D. Dunai , G.I. Pokol , MAST-U Team

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引用次数: 0

Abstract

The MAST-U beam emission spectroscopy (BES) diagnostic measures D

_{α}

emission from the on-axis neutral deuterium heating beam. From the measured light intensity variations, the local density fluctuations can be characterized, which is a valuable method to study both core and edge plasma turbulence, as well as various MHD phenomena. The predecessor 2D turbulence imaging BES diagnostic system was installed on MAST in 2010, with the first mirror location optimized so that measurements had the best achievable poloidal and radial resolution at a specific observation location along the beam. This system was operational in the M8 and M9 campaigns and was successfully used in several physics programs. In the MAST Upgrade, the BES system was relocated due to technical constraints and installed in a dedicated port. The assessment of the new configuration’s spatial resolution was required so that the measurements could be interpreted correctly and consistently. The spatial resolution assessment was performed for multiple observation locations covering the minor radius of the device. Our study concentrated on the dominant smearing caused by the misalignment between the lines of sight and the magnetic field lines within the beam geometry. For comparison, the same analysis was also performed on pre-upgrade scenarios. The relocation of the observation system had a slightly negative effect on the poloidal resolution due to an increase in the misalignment between the lines of sight and the magnetic field lines at the beam location. However, the values in general remain in the region of the old setup, posing no obstacle to the continued utilization of the system for density fluctuation measurements.

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MAST-U光束发射光谱系统磁涂抹效应评估

MAST-U束发射光谱（BES）诊断测量了轴向中性氘加热束的Dα发射。从测量的光强变化可以表征局部密度波动，这是研究核心和边缘等离子体湍流以及各种MHD现象的一种有价值的方法。之前的2D湍流成像BES诊断系统于2010年安装在MAST上，第一个反射镜位置进行了优化，以便在光束的特定观测位置获得最佳的极向和径向分辨率。这个系统在M8和M9战役中运行，并成功地应用于几个物理项目中。在MAST升级中，由于技术限制，BES系统被重新定位并安装在专用端口上。需要对新结构的空间分辨率进行评估，以便能够正确和一致地解释测量结果。对覆盖设备小半径的多个观测位置进行空间分辨率评估。我们的研究主要集中在光束几何结构中由于视线与磁场线的不对准而引起的主要散射。为了进行比较，还对升级前的场景进行了相同的分析。观测系统的重新定位对极向分辨率有轻微的负面影响，因为在波束位置的视线和磁力线之间的不对准增加了。不过，这些数值总体上仍保持在旧设置的范围内，对继续利用该系统进行密度波动测量不构成障碍。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Fusion Engineering and Design 工程技术-核科学技术

CiteScore

3.50

自引率

23.50%

发文量

275

审稿时长

3.8 months

期刊介绍： The journal accepts papers about experiments (both plasma and technology), theory, models, methods, and designs in areas relating to technology, engineering, and applied science aspects of magnetic and inertial fusion energy. Specific areas of interest include: MFE and IFE design studies for experiments and reactors; fusion nuclear technologies and materials, including blankets and shields; analysis of reactor plasmas; plasma heating, fuelling, and vacuum systems; drivers, targets, and special technologies for IFE, controls and diagnostics; fuel cycle analysis and tritium reprocessing and handling; operations and remote maintenance of reactors; safety, decommissioning, and waste management; economic and environmental analysis of components and systems.