Spatial distribution of Ne ions in detached divertor plasmas of JT-60U
Spatial distribution of Ne ions in detached divertor plasmas of JT-60U
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DOI：
10.1016/j.nme.2019.01.020
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发表时间：
2019
影响因子：
2.6
通讯作者：
T. Nakano;N. Asakura
中科院分区：
文献类型：
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作者：
T. Nakano;N. Asakura
计算并合成了氖离子的可见光谱，与真空紫外光谱一致，并与实验光谱进行了比较。没有从高电荷的Ne离子的光谱线被识别，但Ne III（Ne 2+）离子是最高的电荷，产生光谱线在可见光范围内具有足够高的强度被观察到。用计算机层析技术测量了Ne Ⅲ 4f-5g线和C Ⅳ 3s-3 p线的二维可见光谱，重建了发射率分布。发射率分布的比较表明，Ne III发射率在X点的高场侧达到峰值，并且在内部偏滤器分离的情况下，C IV沿着外部偏滤器腿分布，这表明Ne III对X点周围的辐射贡献更大。相反，在附着的情况下，Ne III发射率在X点的高场侧达到峰值，类似于在分离的情况下，但具有较低的强度，而C IV发射率在X点达到峰值，有助于X点辐射。然而，考虑到偏滤器等离子体是附着的，碳辐射不足以使分离开始。
Ne ion visible spectrum, which is consistent with spectra in VUV ranges, is calculated and synthesised for comparison with experimental spectrum. No spectral lines from highly charged Ne ions are identified but Ne III (Ne 2+) ion is the highest charge which yields spectral lines in the visible range with sufficiently high intensity to be observed. Two-dimensional visible spectroscopic measurement of Ne III 4f-5g line and C IV 3s-3p line with an aid of computer tomography technique provides reconstructed emissivity distributions. Comparison of the emissivity distributions reveals that Ne III emissivity is peaked at the high field side of the X-point and C IV is distributed along the outer divertor leg in the case of inner divertor detachment, showing that Ne III contributes more to radiation around the X-point. In contrast, in the case of attachment, Ne III emissivity is peaked at the high field side of the X-point similarly in the detached case but with lower intensity while C IV emissivity is peaked at the X-point, contributing to the X-point radiation. However, given that the divertor plasma is attached, the cabon radiation is not sufficient for detachment onset.