Physics-Informed Latent Space Dynamics Identification for Time-Dependent NLTE Atomic Kinetics

Fuente: arXiv
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Main Authors: Nam, Jeongwoo, Anderson, William, Choi, Youngsoo, Le, Hai P., Foord, Mark E., Cho, Byoung Ick, Jeong, Haewon, Cho, Min Sang
Format: Preprint
Published: 2026
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_version_ 1866913041900109824
author Nam, Jeongwoo
Anderson, William
Choi, Youngsoo
Le, Hai P.
Foord, Mark E.
Cho, Byoung Ick
Jeong, Haewon
Cho, Min Sang
author_facet Nam, Jeongwoo
Anderson, William
Choi, Youngsoo
Le, Hai P.
Foord, Mark E.
Cho, Byoung Ick
Jeong, Haewon
Cho, Min Sang
contents Non-local thermodynamic equilibrium (NLTE) calculations remain a major computational bottleneck in radiation--hydrodynamics, while most existing machine-learning surrogates treat NLTE as a static input--output mapping rather than a kinetic evolution problem. Here, we present a physics-informed Latent Space Dynamics Identification (pLaSDI) framework specifically designed for NLTE atomic kinetics, which captures the time-dependent atomic kinetics of non-equilibrium plasmas through an explicit reduced governing equation. To ensure the physical reliability of the reduced model, we impose physics-informed loss terms that enforce macroscopic consistency, dynamical stability, and convergence to the correct steady state during long-time integration. Applied to tin NLTE population data generated along hydrodynamically modeled temperature--density trajectories relevant to extreme ultraviolet (EUV) lithography plasmas, the model accurately reproduces charge-state evolution and mean charge state with errors below 2\%, achieves speedups of approximately $5\times10^{4}$--$10^{5}$, and remains stable outside the training trajectories by converging toward physically admissible states and the correct steady-state solution under fixed plasma conditions. These results show that careful physics-informed design of the latent dynamics, rather than data fitting alone, is essential for constructing fast, stable, and physically reliable extrapolative surrogates for time-dependent NLTE kinetics.
format Preprint
id arxiv_https___arxiv_org_abs_2604_16664
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Physics-Informed Latent Space Dynamics Identification for Time-Dependent NLTE Atomic Kinetics
Nam, Jeongwoo
Anderson, William
Choi, Youngsoo
Le, Hai P.
Foord, Mark E.
Cho, Byoung Ick
Jeong, Haewon
Cho, Min Sang
Plasma Physics
Computational Physics
Non-local thermodynamic equilibrium (NLTE) calculations remain a major computational bottleneck in radiation--hydrodynamics, while most existing machine-learning surrogates treat NLTE as a static input--output mapping rather than a kinetic evolution problem. Here, we present a physics-informed Latent Space Dynamics Identification (pLaSDI) framework specifically designed for NLTE atomic kinetics, which captures the time-dependent atomic kinetics of non-equilibrium plasmas through an explicit reduced governing equation. To ensure the physical reliability of the reduced model, we impose physics-informed loss terms that enforce macroscopic consistency, dynamical stability, and convergence to the correct steady state during long-time integration. Applied to tin NLTE population data generated along hydrodynamically modeled temperature--density trajectories relevant to extreme ultraviolet (EUV) lithography plasmas, the model accurately reproduces charge-state evolution and mean charge state with errors below 2\%, achieves speedups of approximately $5\times10^{4}$--$10^{5}$, and remains stable outside the training trajectories by converging toward physically admissible states and the correct steady-state solution under fixed plasma conditions. These results show that careful physics-informed design of the latent dynamics, rather than data fitting alone, is essential for constructing fast, stable, and physically reliable extrapolative surrogates for time-dependent NLTE kinetics.
title Physics-Informed Latent Space Dynamics Identification for Time-Dependent NLTE Atomic Kinetics
topic Plasma Physics
Computational Physics
url https://arxiv.org/abs/2604.16664