等离子体湍流中相干结构的非线性过程机制研究

相干结构是湍流中自发产生的一种高度有序的结构，对湍流的发展演化有着重要影响。在磁约束核聚变研究领域，相干结构能够引起显著的粒子和能量输运，并且通过改变湍流性质影响运行模式。因而，对其深入研究对湍流非线性过程的充分认知以及为约束的改善和聚变点火的实现起促进作用。受诊断手段、数据分析方法和理论模型的限制，相干结构的高度非线性相互作用机制仍不十分清楚。本项目将围绕等离子体相干结构的非线性相互作用机制，采用理论辅助实验的方法，开展以下工作：1.升级等离子体实验平台，基于相干结构特性研发多通道诊断技术和先进数据分析方法，研究相干模式非线性演化特征；2.基于本征模表象，建立相干模式相互作用的物理模型；3.结合理论模型和实验结果，定量分析相干结非线性演化机制。项目的创新性结果将有助于揭示湍流及相干结构中复杂的非线性相互作用机制和不同约束模式下的输运过程特性，为优化等离子体运行模式参数提供坚实的物理基础。

Coherent structures are highly ordered self-consistent forms in turbulence, playing important roles in turbulence evolution and development. In magnetic confinement fusion, such structures can cause particle and energy transports, and affect operation scenarios by manipulating turbulence properties. Therefore, study of coherent modes is beneficial to improving confinement and realizing ignition conditions. Limited by existing diagnostic technique, data analyzing method, and theoretical model, the mechanism of the highly non-linear interactions between coherent modes still remains unclear. In this project, focusing on the nonlinear interaction mechanism of plasma coherent structures, following three tasks will be carried out by theory aided experiments: 1. to upgrade the plasma experimental platform, develop a multi-channel diagnostic technique and advanced data analyzing method considering the properties of coherent structures, for investigating non-linear evolution characteristics of the coherent structure; 2. to establish a theretical physics model describing the nonlinear interaction of coherent modes based on the eigenmode representation. 3. to analyze the nonlinear evolution mechanism of the amplitude and phase of coherent structures quantitatively by combining the theoretical model and experimental results. The innovative results will help to reveal the complex nonlinear interaction mechanism in turbulence and coherent structures as well as the transport mechanism under different confinement modes, for providing a solid physical basis for optimizing operation scenarios and plasma parameters.