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arXiv · 2601.02006

Global Hilbert expansion for the ionic Vlasov-Poisson-Boltzmann system

Fucai Li·Yichun Wang
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Abstract

We justify the global-in-time validity of Hilbert expansion for the ionic Vlasov-Poisson-Boltzmann system in $\mathbb{R}^3$, a fundamental model describing ion dynamics in dilute collisional plasmas. As the Knudsen number approaches zero, we rigorously derive the compressible Euler-Poisson system governing global smooth irrotational ion flows. The truncated Hilbert expansion exhibits a multi-layered mathematical structure: the expansion coefficients satisfy linear hyperbolic systems, while the remainder equation couples with a nonlinear Poisson equation for the electrostatic potential. This requires refined elliptic estimates addressing the exponential nonlinearities and some new enclosed $L^2\cap W^{1,\infty}$ estimates for the potential-dependent terms.

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Fucai Li, Yichun Wang. 2026-01-05. Global Hilbert expansion for the ionic Vlasov-Poisson-Boltzmann system. https://arxiv.org/abs/2601.02006

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