论文标题
在计算理论和实验中的边缘等离子湍流建模的物理学的机器学习技术
Physics-informed machine learning techniques for edge plasma turbulence modelling in computational theory and experiment
论文作者
论文摘要
边缘等离子体湍流对于磁限制融合设备的性能至关重要。为了更好地理解理论和实验中的边缘湍流，开发了一个由部分微分方程限制的定制物理知识的深度学习框架，可以准确地学习与电子压力的部分观察结果一致的与两流体理论一致的湍流场。使用常规平衡模型，不可能进行此计算。通过这种技术，在低归一化压力下，在磁化螺旋化等离子体中发现了良好的总体一致性，证明了静电两流体理论和电磁旋转旋转模型之间湍流场的第一个直接定量比较。 为了将这些计算技术转化为实验融合等离子体，通过新创建的深度学习框架将HEI线辐射测量亮度测量转化为局部等离子体波动的新型方法，该框架将中性的传输物理学和碰撞辐射理论整合了$ 3^3^3 D -2^3 D -2^3 d -2^3 p $过渡。本文使用壁c-mod tokamak上的快速摄像机数据，介绍了使用单个光谱线在融合等离子体中的湍流电子密度，电子温度和中性密度的第一个二维实验测量。通过该实验推断的数据，计算了与纯净的纯融合等离子体的框架下，二维湍流电场的初始估计与纯粹的环形场一致。发现原子氦对粒子和能源的影响可以增强电场和电子压力之间的相关性，同时扩大影响$ {\ bf e \ times b} $流和剪切速率的湍流场振幅。
Edge plasma turbulence is critical to the performance of magnetic confinement fusion devices. Towards better understanding edge turbulence in both theory and experiment, a custom-built physics-informed deep learning framework constrained by partial differential equations is developed to accurately learn turbulent fields consistent with the two-fluid theory from partial observations of electron pressure. This calculation is not otherwise possible using conventional equilibrium models. With this technique, the first direct quantitative comparisons of turbulent fields between electrostatic two-fluid theory and electromagnetic gyrokinetic modelling are demonstrated with good overall agreement found in magnetized helical plasmas at low normalized pressure. To translate these computational techniques to experimental fusion plasmas, a novel method to translate brightness measurements of HeI line radiation into local plasma fluctuations is demonstrated via a newly created deep learning framework that integrates neutral transport physics and collisional radiative theory for the $3^3 D - 2^3 P$ transition in atomic helium. Using fast camera data on the Alcator C-Mod tokamak, this thesis presents the first 2-dimensional time-dependent experimental measurements of the turbulent electron density, electron temperature, and neutral density in a fusion plasma using a single spectral line. With this experimentally inferred data, initial estimates of the 2-dimensional turbulent electric field consistent with drift-reduced Braginskii theory under the framework of an axisymmetric fusion plasma with purely toroidal field are calculated. The inclusion of atomic helium effects on particle and energy sources are found to strengthen correlations between the electric field and electron pressure while broadening turbulent field amplitudes which impact ${\bf E \times B}$ flows and shearing rates.
