Effect of reflections on 2D tomographic reconstructions of filtered cameras and on interpreting spectroscopic measurements in the JET ITER-like wall divertor
Effect of reflections on 2D tomographic reconstructions of filtered cameras and on interpreting spectroscopic measurements in the JET ITER-like wall divertor
复制标题
反射对滤波相机的二维断层扫描重建以及对 JET ITER 类壁偏滤器中光谱测量结果解释的影响
DOI：
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发表时间：
2019
影响因子：
1.6
通讯作者：
S. Silburn
中科院分区：
文献类型：
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作者：
J. Karhunen;M. Carr;J. Harrison;B. Lomanowski;I. Balboa;P. Carvalho;M. Groth;A. Huber;G. Matthews;A. Meakins;S. Silburn
考虑到从金属壁表面的反射，在生成断层重建的切向观察，可见光范围内的光谱偏滤器相机在JET已被观察到产生增强的空间精度和显着减少的发射伪影在实验解决的2D线发射分布。在断层扫描过程中的反射被发现导致高估的发射附近的壁表面高达4倍，以及形成明亮的发射伪影之间的主要发射区域和壁表面，包括局部高达50%的发射。通过沿沿着垂直视线积分层析重建来模仿偏滤器光谱测量意味着反射包括所观察到的线积分发射峰的15%-25%。由于光谱视线通过的最亮发射区域的主导地位，不同视线之间的反射贡献的空间差异不如2D重建中明显。然而，后处理EDGE 2D-EIRENE模拟使用CHERAB代码和合成光谱表明，光谱推断偏滤器电子温度下降高达75%，当考虑到由于反射所观察到的光的重新分配。
Considering reflections from metallic wall surfaces in generation of tomographic reconstructions of the tangentially viewing, visible-range spectroscopic divertor cameras in JET has been observed to yield enhanced spatial accuracy and significant reduction of emission artifacts in experimentally resolved 2D line emission distributions. Neglection of reflections in the tomography process was found to lead to overestimation of the emission near the wall surfaces by up to a factor of 4, as well as to formation of bright emission artifacts between the main emission regions and the wall surfaces, comprising locally up to 50% of the emission. Mimicking divertor spectroscopy measurements by integrating the tomographic reconstructions along vertical lines-of-sight implies that reflections comprise 15%–25% of the observed line-integrated emission peaks. The spatial differences in the reflection contribution between the different lines-of-sight are less pronounced than in the 2D reconstructions due to the dominance of the brightest emission regions through which the spectroscopic lines-of-sight pass. However, postprocessing EDGE2D-EIRENE simulations using the CHERAB code and synthetic spectroscopy suggests a decrease of the spectroscopically inferred divertor electron temperature by up to 75%, when redistribution of the observed light due to reflections is considered.