论文标题
通过在Elise测试设施中的发射光谱进行梁表征
Beam characterization by means of emission spectroscopy in the ELISE test facility
论文作者
论文摘要
IPP Garching的Elise测试设施设有RF H-/D-ION源和加速度系统。它的目标是通过提取的电流密度（H/d），共共提取电子和脉冲持续时间来证明ITER NBI系统的性能。 Elise提取区域的大小为ITER NBI的一半。本文介绍了Elise光束差异和均匀性的详细研究。特别是，可以将梁描述为截然不同的两个组件的总和：约2°比5°÷7°。作为测试用例，将梁特性作为两个源参数的函数测量。第一个是流经面向等离子体的等离子网格的电流，以生成磁过滤场。第二个是在等离子体网格和源壁之间流动的偏置电流。滤波场和偏置电流都会影响共提取电子的分数，但在提取系统和梁性质的前面也影响了等离子体的特性。梁的差异和均匀性已通过光束发射光谱（BES）诊断测量； BES收集的原始光谱的详细分析导致描述了两种不同差异成分的光束。该概念得到了诊断量热仪的热成像给出的信息。在加速系统和梁线组件中流动的电流的行为中发现了对所提出的梁模型的进一步支持。这些电流由梁的最不同（带电）颗粒给出。
The ELISE test facility at IPP Garching hosts a RF H-/D- ion source and an acceleration system. Its target is to demonstrate the performance foreseen for the ITER NBI system in terms of extracted current density (H/D), fraction of co-extracted electrons and pulse duration. The size of the ELISE extraction area is half that foreseen for the ITER NBI. This paper presents a detailed study of the ELISE beam divergence and uniformity. In particular, it was possible to describe the beam as the sum of two components at very different divergence: about 2° vs. 5°÷7°. As test cases, the beam properties have been measured as function of two source parameters. The first one is the current flowing through the grid facing the plasma, the Plasma Grid, in order to generate the magnetic filter field. The second one is the bias current flowing between the Plasma Grid and the source walls. Both the filter field and the bias current influence the fraction of co-extracted electrons, but also the properties of the plasma just in front of the extraction system and the beam properties. The divergence and the uniformity of the beam have been measured by a Beam Emission Spectroscopy (BES) diagnostic; the detailed analysis of the raw spectra collected by BES led to describing the beam with two components of different divergence. This concept has been supported by the information given by thermal imaging of the diagnostic calorimeter. Further support to the proposed beam model has been found in the behavior of the currents flowing in the acceleration system and beamline components; these currents are given by the most divergent (charged) particles of the beam.
