arXiv:2512.24205cs.LG2025-12被引 2

用神经网络代理模型加速等离子体不确定性量化,显著降低计算成本。

Micro-Macro Tensor Neural Surrogates for Uncertainty Quantification in Collisional Plasma

  • 构建微-宏分解张量神经网络,降低速度空间维度带来的计算负担。
  • 相比传统蒙特卡洛,方差减少90%以上,仅需少量高精度样本即可获得可靠统计结果。
  • 适用于高维、多尺度等离子体模拟,尤其适合碰撞主导系统中的不确定性分析。

等离子体动力学方程对模型参数和数据的微观扰动极为敏感,因此在预测模拟中进行高效可靠的不确定性量化(UQ)至关重要。然而,传统数值方法面临采样成本高、相空间维度高及多尺度刚性等问题,尤其在存在碰撞时,高维非局部碰撞积分与守恒性质带来额外约束。为此,本文提出一种方差缩减的蒙特卡洛框架用于Vlasov–Poisson–Landau(VPL)系统的不确定性量化,以神经网络代理模型替代多次昂贵的Landau碰撞项计算。该方法结合高保真渐近保持的VPL求解器与低成本、强相关的基于Vlasov–Poisson–Fokker–Planck(VPFP)和欧拉–泊松(EP)方程的代理模型。针对代理模型,我们推广了可分离物理信息神经网络(SPINN),提出一类基于各向异性微-宏分解的张量神经网络,有效降低速度矩计算开销、模型复杂度并缓解维度灾难。为进一步提升与VPL的相关性,校准了VPFP模型,并设计了一种渐近保持型SPINN,其小Knudsen数极限恢复为EP系统,大Knudsen数极限恢复为VP系统。数值实验表明,该方法相比标准蒙特卡洛显著降低方差,以极少高保真样本即可获得准确统计量,且壁时更短,同时对随机维度变化保持鲁棒性。

原文摘要 · Abstract (English)

Plasma kinetic equations exhibit pronounced sensitivity to microscopic perturbations in model parameters and data, making reliable and efficient uncertainty quantification (UQ) essential for predictive simulations. However, the cost of uncertainty sampling, the high-dimensional phase space, and multiscale stiffness pose severe challenges to both computational efficiency and error control in traditional numerical methods. These aspects are further emphasized in presence of collisions where the high-dimensional nonlocal collision integrations and conservation properties pose severe constraints. To overcome this, we present a variance-reduced Monte Carlo framework for UQ in the Vlasov--Poisson--Landau (VPL) system, in which neural network surrogates replace the multiple costly evaluations of the Landau collision term. The method couples a high-fidelity, asymptotic-preserving VPL solver with inexpensive, strongly correlated surrogates based on the Vlasov--Poisson--Fokker--Planck (VPFP) and Euler--Poisson (EP) equations. For the surrogate models, we introduce a generalization of the separable physics-informed neural network (SPINN), developing a class of tensor neural networks based on an anisotropic micro-macro decomposition, to reduce velocity-moment costs, model complexity, and the curse of dimensionality. To further increase correlation with VPL, we calibrate the VPFP model and design an asymptotic-preserving SPINN whose small- and large-Knudsen limits recover the EP and VP systems, respectively. Numerical experiments show substantial variance reduction over standard Monte Carlo, accurate statistics with far fewer high-fidelity samples, and lower wall-clock time, while maintaining robustness to stochastic dimension.

不确定性量化等离子体模拟神经网络代理张量网络

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