近日，德国马克斯普朗克等离子体物理研究所的Matthias Willensdorfer及其研究团队取得一项新进展。经过不懈努力，他们成功观测到边缘局域模式抑制过程托卡马克等离子体中的磁岛。相关研究成果已于2024年10月28日在国际知名学术期刊《自然—物理学》上发表。

本研究表明，这些磁场扰动能够改变等离子体边缘陡峭梯度区域内侧的磁场拓扑结构。研究人员发现了磁岛的特征，其观测结果与边缘局域模的抑制相关联。研究人员将扰动磁面的高分辨率测量结果与理想磁流体动力学理论的预测进行了比较，该理论假设磁场拓扑结构保持不变。

虽然理想磁流体动力学能够充分描述出现边缘局域模的等离子体中的测量结果，但对于这些模式被抑制的等离子体则显得不足。非线性电阻磁流体动力学模型支持了这一观测结果。本研究通过实验证实了磁岛在抑制边缘局域模发生中的预测作用。这将有助于在未来聚变装置中基于物理原理对这些模式进行控制预测。

据悉，在作为聚变能源主要平台的托卡马克装置中，等离子体边缘具有高能量约束和陡峭压力分布时，会出现周期性的丝状等离子体爆发，即边缘局域模。这些边缘局域模可能损坏托卡马克装置的内壁，但可以通过施加小的三维磁场扰动来抑制它们。

附：英文原文

Title: Observation of magnetic islands in tokamak plasmas during the suppression of edge-localized modes

Author: Willensdorfer, Matthias, Mitterauer, Verena, Hoelzl, Matthias, Suttrop, Wolfgang, Cianciosa, Mark, Dunne, Mike, Fischer, Rainer, Leuthold, Nils, Puchmayr, Jonas, Samoylov, Oleg, Surez Lpez, Guillermo, Wendler, Daniel

Issue&Volume: 2024-10-28

Abstract: In tokamaks, a leading platform for fusion energy, periodic filamentary plasma eruptions known as edge-localized modes occur in plasmas with high-energy confinement and steep pressure profiles at the plasma edge. These edge-localized modes could damage the tokamak wall but can be suppressed using small three-dimensional magnetic perturbations. Here we demonstrate that these magnetic perturbations can change the magnetic topology just inside the steep gradient region of the plasma edge. We identify signatures of a magnetic island, and their observation is linked to the suppression of edge-localized modes. We compare high-resolution measurements of perturbed magnetic surfaces with predictions from ideal magnetohydrodynamic theory where the magnetic topology is preserved. Although ideal magnetohydrodynamics adequately describes the measurements in plasmas exhibiting edge-localized modes, it proves insufficient for plasmas where these modes are suppressed. Nonlinear resistive magnetohydrodynamic modelling supports this observation. Our study experimentally confirms the predicted role of magnetic islands in inhibiting the occurrence of edge-localized modes. This will be beneficial for physics-based predictions in future fusion devices to control these modes.

DOI: 10.1038/s41567-024-02666-y

Source: https://www.nature.com/articles/s41567-024-02666-y