A revisit to the Cercignani–Lampis model: Langevin picture and its numerical simulation

Abstract

The Cercignani–Lampis (CL) model for the gas–surface interaction is revisited 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.