Some examples of kinetic scheme whose diffusion limit is Il'in's exponential-fitting

Laurent Gosse (1) , Nicolas Vauchelet (2)

1 IAC - Istituto per le Applicazioni del Calcolo "Mauro Picone"
2 LAGA - Laboratoire Analyse, Géométrie et Applications

This paper is concerned with diffusive approximations of peculiar numerical schemes for several linear (or weakly nonlinear) kinetic models which are motivated by wide-range applications, including radiative transfer or neutron transport, run-and-tumble models of chemotaxis dynamics, and Vlasov-Fokker-Planck plasma modeling. The well-balanced method applied to such kinetic equations leads to time-marching schemes involving a " scattering S-matrix " , itself derived from a normal modes decomposition of the stationary solution. One common feature these models share is the type of diffusive approximation: their macroscopic densities solve drift-diffusion systems, for which a distinguished numerical scheme is Il'in/Scharfetter-Gummel's " exponential fitting " discretization. We prove that the well-balanced schemes relax, within a parabolic rescaling, towards the Il'in exponential-fitting discretization by means of an appropriate decomposition of the S-matrix. This is the so-called asymptotic preserving (or uniformly accurate) property.

Mots clés: Run-and-Tumble; Kinetic well-balanced scheme; Discrete-Ordinates (DO); Diffusive approximation; Exponential fitting scheme; Vlasov-Fokker-Planck; Uniformly accurate scheme

Domaines: Equations aux dérivées partielles [math.AP]

Laurent Gosse, Nicolas Vauchelet. Some examples of kinetic scheme whose diffusion limit is Il'in's exponential-fitting. Numerische Mathematik, 2019, 141 (3), pp.627-680. ⟨hal-01590822v2⟩