Transient analysis of high-Z impurity screening by additional injection of low-Z impurity using integrated divertor code SONIC
Transient analysis of high-Z impurity screening by additional injection of low-Z impurity using integrated divertor code SONIC
复制标题
使用集成偏滤器代码 SONIC 通过额外注入低 Z 杂质来进行高 Z 杂质筛选的瞬态分析
DOI：
10.1088/1741-4326/acd12c
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发表时间：
2023
期刊：
影响因子：
3.3
通讯作者：
Hayashi Nobuhiko
中科院分区：
文献类型：
--
作者：
Yamoto Shohei;Hoshino Kazuo;Homma Yuki;Nakano Tomohide;Hayashi Nobuhiko
通过使用集成偏滤器代码 SONIC 进行时间依赖性分析，研究了注入额外 Ne 的 Ar 杂质筛选效果的动态。在之前的研究中 (Yamoto et al 2020 Plasma Phys. Control. Fusion 62 045006)，SONIC 对 JT-60SA 等离子体的预测模拟表明，与仅 Ar 种子的情况相比，向 Ar 种子等离子体中注入额外的 Ne 会导致 SOL 和核心边缘中的 Ar 密度和辐射功率更低。结果表明，Ar 和 Ne 的混合杂质晶种可能有利于在低偏滤器热负荷下保持高核心等离子体性能。结果发现，在 Ar+ Ne 晶种情况下，SOL 中的高 D+ 流向内偏滤器 (ID) 区域产生的摩擦力将 Ar 杂质推向 ID。然而，在之前的研究中无法解释 D+ 流加速的动力学，因为 SONIC 是稳态代码。在这项研究中，我们开发了 SONIC 的时间相关版本，并将其应用于 JT-60SA 中向 Ar 种子等离子体中注入额外 Ne 的瞬态分析。当注入额外的 Ne 时，Ne 离子停留在 X 点附近的 ID 等离子体中。结果，Ne辐射功率在X点附近增加。然后，电子压力由于辐射冷却而降低，并且 D+ 流因电子压力梯度而加速。由于电子压力梯度加速的 D+ 流的对流，离子压力也会降低。由此产生的离子压力梯度进一步加速了 D+ 流向 ID 的速度。结果表明，Ar+Ne混合杂质引晶可以同时实现高性能核心等离子体和低偏滤器热负荷。
The dynamics of the screening effect of Ar impurity by the injection of additional Ne has been studied through time-dependent analysis with the integrated divertor code SONIC. In the preceding study (Yamoto et al 2020 Plasma Phys. Control. Fusion 62 045006), the predictive simulation of JT-60SA plasma by SONIC has shown that the injection of additional Ne into Ar-seeded plasma results in lower Ar density and radiation power in the SOL and core edge than in the Ar-only seeded case. The results have demonstrated that the mixed impurity seeding of Ar and Ne may be advantageous for maintaining a high core plasma performance with a low divertor heat load. It was found that the friction force induced by the high D+ flow in the SOL towards the inner divertor (ID) region in the Ar+ Ne seeded case pushes Ar impurities to the ID. However, the dynamics of D+ flow acceleration cannot be interpreted in the previous study because SONIC was a steady state code. In this study, we have developed the time-dependent version of SONIC and applied it to the transient analysis of the injection of additional Ne into Ar-seeded plasma in JT-60SA. When additional Ne is injected, Ne ions stay in the ID plasma near the X-point. As a result, the Ne radiation power increases near the X-point. The electron pressure then decreases due to the radiation cooling and the D+ flow is accelerated by the electron pressure gradient. The ion pressure also decreases due to the convection by the accelerated D+ flow by electron pressure gradient. The resulting ion pressure gradient further accelerates the D+ flow velocity towards the ID. The results suggest that both the high-performance core plasma and the low divertor heat load can be achieved by the Ar+ Ne mixed impurity seeding.