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arXiv 2109.02425physics.plasm-ph
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Alcator C-Mod和ASDEX Upgrade托卡马克中的I型基座弛豫事件

I-mode pedestal relaxation events in the Alcator C-Mod and ASDEX Upgrade tokamaks

D. Silvagni, J. L. Terry, W. McCarthy, A. E. Hubbard, T. Eich, M. Faitsch, L. Gil, T. Golfinopoulos, G. Grenfell, M. Griener, T. Happel, J. W. Hughes, U. Stroth… 展开作者

D. Silvagni, J. L. Terry, W. McCarthy, A. E. Hubbard, T. Eich, M. Faitsch, L. Gil, T. Golfinopoulos, G. Grenfell, M. Griener, T. Happel, J. W. Hughes, U. Stroth, E. Viezzer, the ASDEX Upgrade team, the EUROfusion MST1 team

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摘要：

在某些条件下，I模式等离子体可以具有基座弛豫事件（PRE），其瞬时增强到达偏滤器靶板的能量。为了揭示它们的外观、特性和到达偏滤器靶的能量，对两台托卡马克装置$-$ Alcator C-Mod和ASDEX Upgrade $-$进行了对比研究。研究发现，PRE仅出现在I模放电的一个子集中，主要是当等离子体接近H模跃迁时。此外，触发不稳定性的性质进行了讨论，通过比较测量接近两个设备中的分界线。从受限区域的PRE相对能量损失随着基座顶部碰撞性$ν_{\mathrm{ped}}^*$的减小而增加。此外，在基座顶部的相对电子温度下降，这是有关的传导能量损失，增加与减少$ν_{\mathrm{ped}}^*$。最后，将两种装置中偏滤器上测量的PRE引起的峰值平行能量通量与[1]中介绍的I型ELM模型进行比较。该模型提供了一个上边界的PRE能量注量数据，而下边界被发现，通过将模型除以三。这两个边界用于预测未来的设备，如DEMO和ARC。

英文摘要：

In some conditions, I-mode plasmas can feature pedestal relaxation events (PREs) that transiently enhance the energy reaching the divertor target plates. To shed light into their appearance, characteristics and energy reaching the divertor targets, a comparative study between two tokamaks $-$ Alcator C-Mod and ASDEX Upgrade $-$ is carried out. It is found that PREs appear only in a subset of I-mode discharges, mainly when the plasma is close to the H-mode transition. Also, the nature of the triggering instability is discussed by comparing measurements close to the separatrix in both devices. The PRE relative energy loss from the confined region increases with decreasing pedestal top collisionality $ν_{\mathrm{ped}}^*$. In addition, the relative electron temperature drop at the pedestal top, which is related to the conductive energy loss, rises with decreasing $ν_{\mathrm{ped}}^*$. Finally, the peak parallel energy fluence due to the PRE measured on the divertor in both devices is compared to the model introduced in [1] for type-I ELMs. The model is shown to provide an upper boundary for PRE energy fluence data, while a lower boundary is found by dividing the model by three. These two boundaries are used to make projections to future devices such as DEMO and ARC.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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