857 research outputs found
Degenerate anisotropic elliptic problems and magnetized plasma simulations.
International audienceThis paper is devoted to the numerical approximation of a degen- erate anisotropic elliptic problem. The numerical method is designed for arbitrary space-dependent anisotropy directions and does not re- quire any specially adapted coordinate system. It is also designed to be equally accurate in the strongly and the mildly anisotropic cases. The method is applied to the Euler-Lorentz system, in the drift-fluid limit. This system provides a model for magnetized plasmas
Asymptotic-Preserving scheme for a bi-fluid Euler-Lorentz model
The present work is devoted to the simulation of a strongly magnetized plasma
considered as a mixture of an ion fluid and an electron fluid. For the sake of
simplicity, we assume that the model is isothermal and described by Euler
equations coupled with a term representing the Lorentz force. Moreover we
assume that both Euler systems are coupled through a quasi-neutrality
constraint. The numerical method which is described in the present document is
based on an Asymptotic-Preserving semi-discretization in time of a variant of
this two-fluid Euler-Lorentz model with a small perturbation of the
quasi-neutrality constraint. Firstly, we present the two-fluid model and the
motivations for introducing a small perturbation into the quasi-neutrality
equation, then we describe the time semi-discretization of the perturbed model
and a fully-discrete finite volume scheme based on it. Finally, we present some
numerical results which have been obtained with this method
Effcient numerical methods for strongly anisotropic elliptic equations
In this paper, we study an effcient numerical scheme for a strongly anisotropic elliptic problem which arises in the modeling of ionospheric plasma dynamics. A small parameter \varepsilon induces the anisotropy of the problem, which leads to severe numerical diffculties for 0 < \varepsilo
Asymptotic-Preserving methods and multiscale models for plasma physics
The purpose of the present paper is to provide an overview of As ymptotic- Preserving methods for multiscale plasma simulations by ad dressing three sin- gular perturbation problems. First, the quasi-neutral lim it of fluid and kinetic models is investigated in the framework of non magnetized as well as magne- tized plasmas. Second, the drift limit for fluid description s of thermal plasmas under large magnetic fields is addressed. Finally efficient nu merical resolutions of anisotropic elliptic or diffusion equations arising in ma gnetized plasma simu- lation are reviewed
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