arXiv:2511.19114physics.plasm-phcs.AI2025-11被引 3

用物理约束神经算子快速求解核聚变中的非线性格拉德-沙弗兰方程。

Physics-informed Neural Operator Learning for Nonlinear Grad-Shafranov Equation

  • 构建物理信息神经算子,直接学习等离子体平衡解的映射关系。
  • 半监督训练下误差仅0.48%,外推性能比纯数据模型提升8.9倍。
  • 无需大量标注数据,结合物理规律损失函数实现高精度与强泛化。

随着人工智能成为推动核聚变能源商业化的重要力量,快速精准的求解器变得愈发关键。在磁约束核聚变中,快速准确求解非线性格拉德-沙弗兰方程(GSE)对实时等离子体控制与分析至关重要。传统数值求解器虽精度高但计算成本巨大,而数据驱动的代理模型推理快却难以遵守物理定律且泛化能力差。为此,我们提出一种物理信息神经算子(PINO),直接学习从最后一闭合磁面形状参数到平衡解的映射关系。五种神经架构的全面对比表明,新型Transformer-KAN神经算子(TKNO)在监督训练下达到0.25%的均方相对误差,但所有数据驱动模型存在较大物理残差。通过无监督训练引入物理损失项,残差降低近四个数量级,无需标签数据。关键的是,半监督学习——融合稀疏标签数据(100个内点)与物理约束——实现了最佳平衡:插值误差0.48%,外推误差4.76%,退化因子仅为39.8倍的1/8.9。经TensorRT优化后,推理速度达毫秒级,确立PINO作为下一代聚变控制系统有前景的路径。

原文摘要 · Abstract (English)

As artificial intelligence emerges as a transformative enabler for fusion energy commercialization, fast and accurate solvers become increasingly critical. In magnetic confinement nuclear fusion, rapid and accurate solution of the Grad-Shafranov equation (GSE) is essential for real-time plasma control and analysis. Traditional numerical solvers achieve high precision but are computationally prohibitive, while data-driven surrogates infer quickly but fail to enforce physical laws and generalize poorly beyond training distributions. To address this challenge, we present a Physics-Informed Neural Operator (PINO) that directly learns the GSE solution operator, mapping shape parameters of last closed flux surface to equilibrium solutions for realistic nonlinear current profiles. Comprehensive benchmarking of five neural architectures identifies the novel Transformer-KAN (Kolmogorov-Arnold Network) Neural Operator (TKNO) as achieving highest accuracy (0.25% mean L2 relative error) under supervised training (only data-driven). However, all data-driven models exhibit large physics residuals, indicating poor physical consistency. Our unsupervised training can reduce the residuals by nearly four orders of magnitude through embedding physics-based loss terms without labeled data. Critically, semi-supervised learning--integrating sparse labeled data (100 interior points) with physics constraints--achieves optimal balance: 0.48% interpolation error and the most robust extrapolation performance (4.76% error, 8.9x degradation factor vs 39.8x for supervised models). Accelerated by TensorRT optimization, our models enable millisecond-level inference, establishing PINO as a promising pathway for next-generation fusion control systems.

核聚变神经算子物理信息等离子体

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