论文标题
Iter Cold VDE在完美导致第一墙的极限
ITER cold VDEs in the limit of a perfectly conducting first wall
论文作者
论文摘要
最近,已经表明,即使壁是完美的导体,由于当前的淬火,迭代可能会发生垂直位移事件(VDE)[A. A. H. Boozer,等离子体物理学26 114501(2019)]。我们使用带有iTer样平衡的扩展MHD Code M3D-C1,并诱导电流淬火,以使用不同的壁几何形状在完美传导墙的极限探索冷VDE。在特定情况下,侧壁远离等离子体的矩形壁,我们与Boozer开发的分析模型达成了很好的一致性,该模型考虑了顶部/底部平板壁。我们表明,在使侧壁更接近等离子体时,血浆保持在初始平衡位置的解决方案将得到改善。当在完美导体的限制下使用ITER第一壁时,等离子体在初始平衡位置保持稳定,远远超出了平板壁极限所预测的值。另一方面,当考虑到iTer真空容器的内壳充当完美导体时,等离子体在当前淬火期间位移,但是与平板壁限制相比,边缘安全系数在当前衰减中保持更长的价格。在所有模拟情况下,都发现垂直位移很大程度上取决于等离子体电流,这与平板壁极限中的相似发现一致,显示出与通常的VDE有重要的差异,其中电流淬火不是必要的条件。
Recently, it has been shown that a vertical displacement event (VDE) can occur in ITER even when the walls are perfect conductors, as a consequence of the current quench [A. H. Boozer, Physics of Plasmas 26 114501 (2019)]. We used the extended-MHD code M3D-C1 with an ITER-like equilibrium and induced a current quench to explore cold VDEs in the limit of perfectly conducting walls, using different wall geometries. In the particular case of a rectangular wall with the side walls far away from the plasma, we obtained very good agreement with the analytical model developed by Boozer that considers a top/bottom flat-plates wall. We show that the solution in which the plasma stays at the initial equilibrium position is improved when bringing the side walls closer to the plasma. When using the ITER first wall in the limit of a perfect conductor, the plasma stays stable at the initial equilibrium position far beyond the value predicted by the flat-plates wall limit. On the other hand, when considering the limit in which the inner shell of the ITER vacuum vessel is acting as a perfect conductor, the plasma is displaced during the current quench but the edge safety factor stays above $2$ longer in the current decay compared to the flat-plates wall limit. In all the simulated cases, the vertical displacement is found to be strongly dependent on the plasma current, in agreement with a similar finding in the flat-plates wall limit, showing an important difference with usual VDEs in which the current quench is not a necessary condition.