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arXiv 2311.05967physics.plasm-phcs.LG
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基于傅里叶神经算子的等离子体代理建模

Plasma Surrogate Modelling using Fourier Neural Operators

Caltech(加州理工学院)
Vignesh Gopakumar, Stanislas Pamela, Lorenzo Zanisi, Zongyi Li, Ander Gray, Daniel Brennand, Nitesh Bhatia, Gregory Stathopoulos, Matt Kusner, Marc Peter Deisen… 展开作者

Vignesh Gopakumar, Stanislas Pamela, Lorenzo Zanisi, Zongyi Li, Ander Gray, Daniel Brennand, Nitesh Bhatia, Gregory Stathopoulos, Matt Kusner, Marc Peter Deisenroth, Anima Anandkumar, JOREK Team, MAST Team

AI总结:

针对托卡马克等离子体演化数值求解成本高的问题,提出基于改进傅里叶神经算子的代理模型,速度较传统求解器快6个数量级,可用于仿真与真实实验数据的等离子体演化预测及实时监测。

摘要:

预测托卡马克反应堆内的等离子体演化对于实现可持续聚变目标至关重要。快速、准确地预测等离子体时空演化的能力,使我们能够在现有托卡马克装置和未来反应堆上快速迭代设计与控制策略。使用数值求解器对等离子体演化建模通常计算成本极高,需要在超级计算机上耗费数小时,因此我们需要成本更低的替代代理模型。\n我们利用基于深度学习的代理建模工具,即傅里叶神经算子(Fourier Neural Operators,FNO),在仿真和实验两个领域均实现了等离子体演化的准确预测。研究表明,在预测由磁流体动力学模型仿真得到的等离子体动力学行为时,FNO的速度比传统求解器快6个数量级,同时保持了高精度(归一化域内的均方误差MSE约为$10^{-5}$)。我们改进后的FNO版本能够求解多变量偏微分方程(Partial Differential Equations,PDE),且可在单个模型中捕捉不同变量之间的依赖关系。\nFNO还能基于MAST托卡马克内部摄像机(即观测托卡马克中心螺线管和偏滤器的摄像机)采集的真实实验数据,预测等离子体演化。我们证实FNO能够准确预测等离子体的演化过程,具备部署用于实时监测的潜力。此外,我们还展示了FNO在预测等离子体形状、等离子体与中心螺线管及偏滤器的相互作用位置方面的能力,覆盖MAST中等离子体放电的全部(可用)持续时间。FNO训练和推理速度快、所需数据点更少,还能实现零样本超分辨率并得到高保真解,是代理建模的可行替代方案。

英文摘要:

Predicting plasma evolution within a Tokamak reactor is crucial to realizing the goal of sustainable fusion. Capabilities in forecasting the spatio-temporal evolution of plasma rapidly and accurately allow us to quickly iterate over design and control strategies on current Tokamak devices and future reactors. Modelling plasma evolution using numerical solvers is often expensive, consuming many hours on supercomputers, and hence, we need alternative inexpensive surrogate models. We demonstrate accurate predictions of plasma evolution both in simulation and experimental domains using deep learning-based surrogate modelling tools, viz., Fourier Neural Operators (FNO). We show that FNO has a speedup of six orders of magnitude over traditional solvers in predicting the plasma dynamics simulated from magnetohydrodynamic models, while maintaining a high accuracy (MSE in the normalised domain $\approx$ $10^{-5}$). Our modified version of the FNO is capable of solving multi-variable Partial Differential Equations (PDE), and can capture the dependence among the different variables in a single model. FNOs can also predict plasma evolution on real-world experimental data observed by the cameras positioned within the MAST Tokamak, i.e., cameras looking across the central solenoid and the divertor in the Tokamak. We show that FNOs are able to accurately forecast the evolution of plasma and have the potential to be deployed for real-time monitoring. We also illustrate their capability in forecasting the plasma shape, the locations of interactions of the plasma with the central solenoid and the divertor for the full (available) duration of the plasma shot within MAST. The FNO offers a viable alternative for surrogate modelling as it is quick to train and infer, and requires fewer data points, while being able to do zero-shot super-resolution and getting high-fidelity solutions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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