The boundary conditions (BCs) involving a plasma-wall transition (PWT) are crucial when estimating the particle and heat fluxes at the wall, and when simulating the edge plasma with fluid, gyro-kinetic and gyro-fluid codes. The aim of this work was to derive time-dependent BCs at the PWT for ELM-free, Type-I ELM and post-ELM states based on a kinetic test simulation in the ITER tokamak without neutrals, so as to obtain the steady state. This contribution describes the first results of attempts to address this issue for ITER simulations under high-performance conditions using the 1D3V electrostatic parallel Particle-in-Cell code BIT1 (Tskhakaya in Plasma Phys Control Fusion 59(11401):19pp, 2017). The burning plasma conditions correspond to the ITER Q = 10, 15 MA baseline at $$q_{95}$$ q 95 = 3, for which the poloidal length of the 1D SOL is $$\sim$$ ∼ 20 m from the inner to the outer target, assuming typical upstream separatrix parameters of $$n_e$$ n e $$\sim$$ ∼ 3 to 5 $$\cdot 10^{19}$$ · 10 19 m $$^{-3}$$ - 3 , $$T_e$$ T e $$\sim$$ ∼ 100 to 150 eV and $$T_i$$ T i $$\sim$$ ∼ 200 to 300 eV. Inclined magnetic fields at targets of ( $$\sim 5^{\circ }$$ ∼ 5 ∘ ) are included, as are the particle collisions, with a total of 3.4 $$\cdot 10^{5}$$ · 10 5 poloidal grid cells, giving shortening factors of 20. The results show that for the ELM-free state the BCs relate to the classic one; in the phase of the Type-I ELM, the BCs are increasing; and in the post-ELM, the BCs are decreasing, reaching the classic values. Taking into account this kind of BC dependence, we can provide realistic ITER plasma profiles for subsequent investigations. As this is a time-consuming process, the simulations are first conducted without neutrals, while in order to obtain realistic values for the BCs, the neutrals are added to the system. At a later stage, these will be used as BCs for the calculations of the ELM target heat loads using the SOLPS-ITER (Bonnin in Plasma Fusion Res 11:1403102, 2016; Wiesen in J Nucl Mater 463:480–484, 2015) code.

中文翻译：

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ITER 等离子体中 ELM 期间的瞬态边界条件

在估计壁上的粒子和热通量以及使用流体、陀螺动力学和陀螺流体代码模拟边缘等离子体时，涉及等离子体壁转变 (PWT) 的边界条件 (BC) 至关重要。这项工作的目的是基于无中性点的 ITER 托卡马克中的动力学测试模拟，在无 ELM、I 型 ELM 和后 ELM 状态的 PWT 上推导时间相关的 BC，以获得稳态。本贡献描述了使用 1D3V 静电并行 Particle-in-Cell 代码 BIT1（Tskhakaya in Plasma Phys Control Fusion 59(11401):19pp, 2017）在高性能条件下尝试解决 ITER 模拟问题的第一个结果。燃烧等离子体条件对应于 ITER Q = 10, 15 MA 基线在 $$q_{95}$$ q 95 = 3，对于其中一维 SOL 的极向长度为 $$\sim$$ ∼ 20 m 从内部目标到外部目标，假设典型的上游分离线参数 $$n_e$$ ne $$\sim$$ ∼ 3 to 5 $ $\cdot 10^{19}$$ · 10 19 m $$^{-3}$$ - 3 , $$T_e$$ T e $$\sim$$ ∼ 100 到 150 eV 和 $$T_i$$ T i $$\sim$$ ~ 200 到 300 eV。包括 ( $$\sim 5^{\circ }$$ ∼ 5 ∘ ) 目标处的倾斜磁场，以及粒子碰撞，总共 3.4 $$\cdot 10^{5}$$ · 10 5 个极向网格单元，缩短因子为 20。结果表明，对于无 ELM 状态，BC 与经典状态相关；在 I 类 ELM 阶段，BC 正在增加；而在后ELM中，BCs正在减少，达到经典值。考虑到这种 BC 依赖性，我们可以为后续研究提供现实的 ITER 等离子体轮廓。由于这是一个耗时的过程，因此首先在没有中性点的情况下进行模拟，而为了获得 BC 的实际值，将中性点添加到系统中。在稍后阶段，这些将用作使用 SOLPS-ITER 计算 ELM 目标热负荷的 BC（Bonnin in Plasma Fusion Res 11:1403102, 2016; Wiesen in J Nucl Mater 463:480–484, 2015）代码。