A novel double-peaked emission profile has been observed by the visible light imaging system in EAST. In the upper divertor region, two emission peaks in the high-field side (HFS) scrape-off layer (SOL) and near the X-point are identified by tomographic reconstruction. In our previous SOLPS-ITER simulation work, the emission peaks in the HFS SOL and near the X-point are attributed to the carbon deposition on the HFS baffle and the dome of the upper tungsten divertor, respectively. The appearance of the emission peak near the X-point when the outer target is attached was understood by analysing the carbon transport in the private flux region (PFR). However, the simulated intensity of the emission peak in the HFS SOL is lower by one order of magnitude than that in the PFR, while they are at the similar level in the experiment. In this work, the influence of the drifts is further studied by SOLPS-ITER simulations. Under the favourable toroidal field condition, the HFS SOL plasma transits to the detachment regime. The chemical sputtering of the carbon deposited on the inner baffle increases significantly, as well as the emission intensity of the peak in the HFS SOL. Meanwhile, the C²⁺ density peak in the PFR decreases due to the E × B drift towards inner target. The emission intensity in the PFR near the X-point, therefore, decreases moderately. As a result, the intensities of the two emission peaks become comparable, which matches better with the experiment.

中文翻译：

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漂移对EAST上偏滤器区可见光双峰发射剖面的影响

EAST 的可见光成像系统观察到了一种新的双峰发射曲线。在偏滤器上部区域，通过断层重建识别高场侧 (HFS) 刮除层 (SOL) 和 X 点附近的两个发射峰。在我们之前的 SOLPS-ITER 模拟工作中，HFS SOL 中和 X 点附近的发射峰分别归因于 HFS 挡板和上钨偏滤器圆顶上的碳沉积。通过分析私有通量区域 (PFR) 中的碳传输，了解了当附加外部目标时 X 点附近的排放峰的出现。然而，HFS SOL 中发射峰的模拟强度比 PFR 中的低一个数量级，而它们在实验中处于相似的水平。在这项工作中，SOLPS-ITER 模拟进一步研究了漂移的影响。在有利的环形场条件下，HFS SOL 等离子体转变为脱离状态。沉积在内挡板上的碳的化学溅射显着增加，以及 HFS SOL 中峰的发射强度。同时，C由于E  ×  B向内部目标漂移， PFR 中的^{2+密度峰降低。}因此，X 点附近的 PFR 中的发射强度适度降低。结果，两个发射峰的强度变得可比，这与实验更好地匹配。