EAST托卡马卡上利用共振磁扰动控制边界局域模实验中三维新经典输运效应研究

The application of Resonant Magnetic Perturbation (RMP) for Edge Localized Mode (ELM) control, which is currently a very active area of research in Fusion community, has been demonstrated as one of the most effective methods and it had minor influence on the overall plasma confinement. Therefore, it has been chosen for type-I ElM control on ITER to solve the problem in transient pulsed local particle and heat load induced by uncontrolled type-I ELM, which may significantly damage the surface of the divertor and the first wall and reduce the lifetime of them. However, the observations on different machines about ELM control with RMP were very different, and the mechanism is still not quite clear. EAST tokamak, similar to ITER aiming for long pulse steady state operation, has recently equipped with a new in-vessel RMP coil system for MHD instabilities control. It is a flexible system for ELM control. This proposal aims to understand the mechanism in ELM control with RMP in ITER-like configuration and low torque condition on EAST via detailed studies in the changes in three dimentional shaping of the field due to different RMP configuration including plasma response and the resultant neoclassical transport on the pedestal profiles and peeling-ballooning stability.

利用共振磁扰动控制边界局域模是目前国际聚变界的研究热点，并且被证明是最有效的方法之一，同时能够保证整体约束变化不大。 因此，ITER也计划采用这种方法以解决第一类边界局域模引起的巨大的瞬间粒子流和热流对偏滤器靶板和第一壁表面的损伤从而影响他们的寿命。然而,不同装置上这种方法的观察效果很不一致，这一控制过程的物理机制还很不清楚。作为类似ITER同样致力于稳态长脉冲运行的EAST托卡马克最近也在真空室内安装了一套共振磁扰动线圈系统，用于磁流体力学不稳定性的控制。对于ELM控制而言，这是一套非常灵活的系统。本项目申请的目的是在EAST上类似ITER的位型、共振磁扰动模式及低力矩注入的条件下的边界局域模主动控制中，通过细致地研究共振磁扰动对磁场位型三维形变影响，及由此导致的三维新经典输运对台基区分布及模的稳定性的影响，理解边界局域模的控制机制。

本项目致力于在EAST上开展类似ITER条件下，利用新发展的共振磁扰动线圈系统开展边界局域模控制的实验研究，通过细致地研究等离子对共振磁扰动的响应、共振磁扰动对边界等离子体约束输运以及台基稳定性的影响，理解边界局域模的控制机制。在本项目的支持下，我们成功地在EAST上实现了低动量注入条件下的边界局域模（ELM）的有效控制，这一手段不仅可以有降低边界局域模崩塌强度，还可以实现对其完全抑制作用。直接观察到了边界局域模抑制过程中的磁扰动非线性跳变，揭示了边界局域模抑制的关键机理。观察到了边界局域模的控制效果与谱型共振性的依赖关系，并与理论模拟结果一致。我们在EAST和DIII-D上提出并验证了混合扰动模式对边界局域模和靶板热负荷的有效控制。结合独立发展的数值模拟程序以及引进其它重要模拟程序，在控制机理相关的等离子体响应、新经典环向粘滞、磁扰动渗透、边界三维拓扑结构等等关键物理方面取得系列重要的研究成果。在Phys. Rev. Letts. 和 Nucl.Fusion等杂志上发表并标注支持的相关论文14篇，并获得美国的APS、国际原子能机构的IAEA-FEC等国际大会的邀请报告或口头报告数次。相关研究结果将增强将这一控制手段推广到未来聚变堆应用上的信心。