The understanding of the halo current properties during disruptions is key to design and operate large scale tokamaks in view of the large thermal and electromagnetic loads that they entail. For the first time, we present a fully self-consistent model for halo current simulations including neutral particles and sheath boundary conditions. The model is used to simulate vertical displacement events (VDEs) occurring in the COMPASS tokamak. Recent COMPASS experiments have shown that the parallel halo current density at the plasma-wall interface is limited by the ion saturation current during VDE-induced disruptions. We show that usual magneto-hydrodynamic boundary conditions can lead to the violation of this physical limit and we implement this current density limitation through a boundary condition for the electrostatic potential. Sheath boundary conditions for the density, the heat flux, the parallel velocity and a realistic parameter choice (e.g. Spitzer’s resistivity and Spitzer–Hrm parallel thermal conductivity) extend present VDE simulations beyond the state of the art. Experimental measurements of the current density, temperature and heat flux profiles at the COMPASS divertor are compared with the results obtained from axisymmetric simulations. Since the ion saturation current density () is shown to be essential to determine the halo current profile, parametric scans are performed to study its dependence on different quantities such as the plasma resistivity and the particle and heat diffusion coefficients. In this respect, the plasma resistivity in the halo region broadens significantly the profile, increasing the halo width at a similar total halo current.

鉴于大型托卡马克所带来的巨大热负荷和电磁负荷，了解中断期间的晕流特性是设计和运行大型托卡马克的关键。我们首次提出了一个完全自洽的晕流模拟模型，包括中性粒子和鞘边界条件。该模型用于模拟 COMPASS 托卡马克中发生的垂直位移事件 (VDE)。最近的 COMPASS 实验表明，在 VDE 引起的破坏期间，等离子体-壁界面处的平行晕圈电流密度受到离子饱和电流的限制。我们表明，通常的磁流体动力学边界条件会导致违反此物理限制，并且我们通过静电势的边界条件来实现此电流密度限制。密度、热通量、平行速度和实际参数选择（例如斯皮策电阻率和斯皮策-Hrm 平行热导率）的护套边界条件使现有 VDE 模拟超出了现有技术水平。将 COMPASS 偏滤器处电流密度、温度和热通量分布的实验测量值与轴对称模拟获得的结果进行比较。由于离子饱和电流密度 ( COMPASS 偏滤器的温度和热通量分布与轴对称模拟获得的结果进行了比较。由于离子饱和电流密度 ( COMPASS 偏滤器的温度和热通量分布与轴对称模拟获得的结果进行了比较。由于离子饱和电流密度 () 被证明是确定光晕电流分布的必要条件，因此执行参数扫描以研究其对不同量的依赖性，例如等离子体电阻率以及粒子和热扩散系数。在这方面，晕区中的等离子体电阻率显着加宽了轮廓，在相似的总晕电流下增加了晕宽度。