The dynamics at the edge of fusion confinement devices is driven by interchange instabilities and involves the motion of plasma across two regions—the “core region” and the scrape-off layer (SOL)—distinguished by whether field lines are, respectively, closed or connected to the wall. Motivated by this phenomenon, we present an extensive linear stability analysis of a two-layer plasma model encompassing the coupled interactions between the region with closed field lines and the SOL. We focus on the effect of varying the particle diffusivity and ion viscosity, revealing the significant variation in the spatial structure of the critical modes. In addition, we have investigated the dependence of the stability threshold on the ratio of the width of the region with closed field lines to that of the SOL; this dependence is strong when the ratio is sufficiently small, but becomes insignificant once the ratio is of order unity.

中文翻译：

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耦合核心-SOL等离子体中的交换不稳定性开始

聚变约束装置边缘的动力学由交换不稳定性驱动，涉及等离子体跨越两个区域的运动——“核心区域”和刮除层 (SOL)——通过场线分别是闭合还是闭合来区分与墙壁相连。受这种现象的启发，我们对两层等离子体模型进行了广泛的线性稳定性分析，包括具有闭合场线的区域与 SOL 之间的耦合相互作用。我们专注于改变粒子扩散率和离子粘度的影响，揭示了临界模式空间结构的显着变化。此外，我们研究了稳定性阈值对具有闭合场线的区域的宽度与 SOL 的宽度之比的依赖性；