SOLPS5.1 analysis of detachment with drifts and gas pumping effects in EAST
SOLPS5.1 analysis of detachment with drifts and gas pumping effects in EAST
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DOI：
10.1088/0741-3335/58/8/085006
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发表时间：
2016-07
影响因子：
2.2
通讯作者：
H. Du;C. Sang;Liang Wang;X. Bonnin;Houyang Y Guo;Ji-zhong Sun;Dezhen Wang
中科院分区：
文献类型：
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作者：
H. Du;C. Sang;Liang Wang;X. Bonnin;Houyang Y Guo;Ji-zhong Sun;Dezhen Wang
利用边缘等离子体程序包SOLPS5.1计算了实验先进超导托卡马克（EAST）装置中常见漂移和吹气/抽气位置对偏滤器分离和Ar离子输运的影响。模拟结果表明，哪个靶板首先分离强烈地取决于通常的漂移，但不取决于杂质气体抽吸的位置，这可能是对实验观察到的现象（Chen等人2013 Phys. Plasmas 20 022311）的可能解释之一，即与具有较低外部气体抽吸的较低外部靶相比，较低内部靶首先分离。这一现象背后的物理原因是漂移不仅可以引起背景离子通量、等离子体密度和温度在刮除层（SOL）和偏滤器区域的重新分布，而且可以改变Ar杂质力平衡，导致Ar离子从底部被拖到顶部。此外，模拟结果还表明，在部分脱离前，包括偏滤器区和上游区在内的不同吹气位置下，Ar离子在SOL和偏滤器区的输运是相似的。然而，Ar离子更容易渗透到核心中，在完全分离期间，上游气体抽吸比偏滤器区域抽吸引起更多的放电中断。最后，我们还估算了在EAST实现长脉冲部分脱离所需的抽气对脱离的影响。结果表明，在EAST部分分离过程中，当等离子体中积累了过量Ar原子时，通过提高抽运速度使之与吹气速度相匹配，可以实现长脉冲部分分离。
The aim of this paper is to estimate the effects of usual drifts and gas puffing/pumping locations on divertor detachment and Ar ion transport in the Experimental Advanced Superconducting Tokamak (EAST) by using the edge plasma code package SOLPS5.1. The simulated results reveal that which target plate first detaches depends strongly on the usual drifts, but not on the location of impurity gas puffing, which could be one of the possible explanations for the experimentally observed phenomenon (Chen et al 2013 Phys. Plasmas 20 022311) that the lower inner target first detached compared to the lower outer target with the lower outer gas puffing. The physics behind this phenomenon is that drifts not only can induce background ion flux, plasma density and temperature redistribution in the scrape-off layer (SOL) and divertor region, but also can change the Ar impurity force balance leading to Ar ions being dragged from bottom to top. Furthermore, the simulated results illustrate that the Ar ion transport in the SOL and divertor region is similar for different gas puffing locations including upstream and divertor region before partial detachment. However, the Ar ions penetrate into the core more easily, giving rise to more discharge disruption during complete detachment with upstream gas puffing than with divertor region puffing. Finally, we also estimate the effect of gas pumping on the detachment in order to realize long-pulse partial detachment in EAST. The results indicate that long-pulse partial detachment could be obtained by improving the pumping speed to match the puffing speed in case the excess Ar atoms accumulate in the core plasma during partial detachment in EAST.