arXiv:2606.15512cs.LGphysics.plasm-ph2026-06

用神经算子实现跨装置高效等离子体平衡重建,提升实时控制能力。

Towards Data-Efficient Cross-Device Generalization of Grad-Shafranov Equilibria via Transfer Learning Neural Operator

论文配图:Towards Data-Efficient Cross-Device Generalization of Grad-Shafranov Equilibria via Transfer Learning Neural Operator
图 1 · 摘自论文原文
  • 将平衡重建转为跨装置算子学习,直接从几何与参数预测磁通场。
  • 仅需100个目标数据即可达4%以下误差,全微调后低于2%。
  • 支持毫秒级推理,适合融合装置实时控制场景。

实时重构磁流体动力学平衡对磁约束聚变中的等离子体形状调控、稳定性评估和反馈控制至关重要。然而,传统的Grad-Shafranov平衡计算高度依赖设备且为迭代求解,难以用于时延敏感的控制场景。现有神经方法虽可加速单设备预测,但无法跨不同等离子体边界或托卡马克几何复用。本文提出将平衡重建建模为跨装置算子学习问题,构建专用神经算子框架,直接从几何与剖面参数映射至环向磁通场,替代反复求解。以解析可处理的Solov'ev族为测试基准,生成8种几何各异的托卡马克类构型的平衡态,对比五种神经算子架构在四种迁移学习策略下的表现。单设备预训练迁移效果差,多设备预训练则实现数据高效适配。小波神经算子表现最优,在100个标注目标平衡态下平均相对L2误差低于4%,全微调后低于2%。预测磁场满足数值精度下的无散度约束,四种架构推理时间达毫秒或亚毫秒级。结果表明,神经算子预训练是实现跨装置可复用、实时平衡推断的有效路径。

原文摘要 · Abstract (English)

Real-time reconstruction of magnetohydrodynamic equilibria is essential for plasma shaping, stability assessment and feedback control in magnetic confinement fusion. However, Grad-Shafranov equilibrium calculations remain largely device-specific and iterative, limiting their use in latency-constrained control settings. Existing neural approaches can accelerate individual equilibrium predictions, but they do not generally provide reusable models across changing plasma boundaries or tokamak geometries. Here we show that equilibrium reconstruction can be recast as a cross-device operator learning problem. We develop a domain-specific neural operator framework that maps geometry and profile parameters directly to the poloidal flux field, replacing repeated solve-on-demand computation with amortized operator inference. Using the analytically tractable Solov'ev family as a controlled Grad-Shafranov testbed, we generate equilibria across eight geometrically distinct tokamak-like configurations and benchmark five neural operator architectures under four transfer-learning strategies. Single-geometry pretraining gives poor transfer to unseen devices, whereas multi-geometry pretraining enables data-efficient adaptation. The Wavelet Neural Operator gives the strongest cross-geometry performance, reaching mean relative L2 errors below 4% with 100 labelled target equilibria and below 2% with full fine-tuning. The predicted magnetic fields satisfy the divergence-free constraint to numerical precision, and four architectures achieve millisecond or sub-millisecond inference. These results identify neural operator pretraining as a route towards reusable, real-time equilibrium inference across fusion device configurations.

神经算子等离子体迁移学习融合控制

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