A Revisit to the Cercignani–Lampis Model: Langevin Picture and Its Numerical Simulation
A Revisit to the Cercignani–Lampis Model: Langevin Picture and Its Numerical Simulation
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重温 Cercignani-Lampis 模型：Langevin 图片及其数值模拟
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发表时间：
2021
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通讯作者：
Masanari Hattori
中科院分区：
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作者：
S. Takata;Shigenori Akasobe;Masanari Hattori
从朗之万动力学的角度重新讨论了气体-表面相互作用的Cercignani-Lampis(CL)模型。从Cercignani提出的与时间无关的Fokker-Planck形式出发，介绍了它的含时推广和相应的朗之万式。朗之万描述揭示了与CL模型相对应的随机过程的动力学特征。在朗之万描述的基础上进行了数值模拟，数值地再现了散射核和fl反射强度分布。虽然随机过程中的噪声显然很简单，但为了在时间离散上达到满意的数值收敛，必须采用Milstein格式而不是Euler-Maruyama格式。
The Cercignani–Lampis (CL) model for the gas–surface interaction is re-visited from the Langevin dynamics viewpoint. Starting from a time-independent Fokker–Planck formalism by Cercignani, its time-dependent extension and the corresponding Langevin description are introduced. The Langevin description sheds light on dynamical features of a stochastic process corresponding to the CL model. Numerical simulations on the basis of the Langevin description are performed as well to reproduce the scattering kernel and reflection intensity distribution numerically. Although the noise in the stochastic process is apparently simple, the Milstein scheme rather than the Euler–Maruyama scheme has to be adopted to achieve a satisfactory numerical convergence in time discretisation.