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A hyperbolic system approach is proposed for robust computation of anisotropic diffusion equations that appear in quasineutral plasmas. Though the approach exhibits merits of high extensibility and accurate flux computation, the…

Numerical Analysis · Mathematics 2025-09-12 Tokuhiro Eto , Rei Kawashima

We develop an asymptotic preserving scheme for the gray radiative transfer equation. Two asymptotic regimes are considered: one is a diffusive regime described by a nonlinear diffusion equation for the material temperature; the other is a…

Numerical Analysis · Mathematics 2019-09-17 Min Tang , Li Wang , Xiaojiang Zhang

An asymptotic model based on a reductive perturbative expansion of the drift kinetic and the Maxwell equations is used to demonstrate that, near the instability threshold, the nonlinear dynamics of mirror modes in a magnetized plasma with…

Plasma Physics · Physics 2015-05-13 E. A. Kuznetsov , T. Passot , P. L. Sulem

This paper deals with the numerical resolution of the Vlasov-Poissonsystem with a strong external magnetic field by Particle-In-Cell(PIC) methods. In this regime, classical PIC methods are subject tostability constraints on the time and…

Numerical Analysis · Mathematics 2015-11-24 Francis Filbet , Luis Miguel Rodrigues

In this article, we design Asymptotic-Preserving Particle-In-Cell methods for the Vlasov-Maxwell system in the quasi-neutral limit, this limit being characterized by a Debye length negligible compared to the space scale of the problem.…

Plasma Physics · Physics 2015-09-15 Pierre Degond , Fabrice Deluzet , David Doyen

A new set of nonlinear coupled equations is derived in the context of small amplitude limit of the general wave equations in a fluid type warm electrons/cold ions plasma irradiated by a continuous laser beam. This limit is proved to be…

Exactly Solvable and Integrable Systems · Physics 2016-06-22 A. Latifi

We investigate the fractional diffusion approximation of a kinetic equation in the upper-half plane with diffusive reflection conditions at the boundary. In an appropriate singular limit corresponding to small Knudsen number and long time…

Analysis of PDEs · Mathematics 2019-09-04 Ludovic Cesbron , Antoine Mellet , Marjolaine Puel

We consider a class of multiscale parabolic problems with diffusion coefficients oscillating in space at a possibly small scale $\varepsilon$. Numerical homogenization methods are popular for such problems, because they capture efficiently…

Numerical Analysis · Mathematics 2016-08-18 Nicolas Crouseilles , Mohammed Lemou , Gilles Vilmart

In this work, high order asymptotic preserving schemes are constructed and analysed for kinetic equations under a diffusive scaling. The framework enables to consider different cases: the diffusion equation, the advection-diffusion equation…

Numerical Analysis · Mathematics 2023-05-24 Megala Anandan , Benjamin Boutin , Nicolas Crouseilles

We investigate the properties of natural two-dimensional (2D) magnetoplasma modes in laterally confined electron systems, such as 2D materials, quantum wells, or inversion layers in semiconductors, with an elliptic Fermi surface. The…

Mesoscale and Nanoscale Physics · Physics 2025-11-18 D. A. Rodionov , I. V. Zagorodnev

The concern of this work is the generalization of an Asymptotic Preserving method for the highly anisotropic elliptic equations presented in [P. Degond, A. Lozinski, J. Narski, and C. Negulescu. An asymptotic-preserving method for highly…

Numerical Analysis · Mathematics 2013-02-19 Jacek Narski

We study the effect of the non-linear process of ambipolar diffusion (joint transport of magnetic flux and charged particles relative to neutral particles) on the long-term behavior of a non-uniform magnetic field in a one-dimensional…

Solar and Stellar Astrophysics · Physics 2015-05-18 Jaime Hoyos , Andreas Reisenegger , Juan Valdivia

Astrophysical fluids under the influence of magnetic fields are often subjected to single-fluid or two-fluid approximations. In the case of weakly ionized plasmas however, this can be inappropriate due to distinct responses from the…

Astrophysics · Physics 2008-11-26 S. O'Sullivan , T. P. Downes

We consider anisotropic heat flow with extreme anisotropy, as arises in magnetized plasmas for fusion applications. Such problems pose significant challenges in both obtaining an accurate approximation as well in the construction of an…

Numerical Analysis · Mathematics 2024-12-12 Maria Vasilyeva , Golo A. Wimmer , Ben S. Southworth

Diffuse domain methods (DDMs) have garnered significant attention for approximating solutions to partial differential equations on complex geometries. These methods implicitly represent the geometry by replacing the sharp boundary interface…

Analysis of PDEs · Mathematics 2025-04-25 Toai Luong , Tadele Mengesha , Steven M. Wise , Ming Hei Wong

This work is devoted to the numerical simulation of a Vlasov-Poisson model describing a charged particle beam under the action of a rapidly oscillating external electric field. We construct an Asymptotic Preserving numerical scheme for this…

Numerical Analysis · Mathematics 2015-06-11 Nicolas Crouseilles , Mohammed Lemou , Florian Méhats

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…

Mathematical Physics · Physics 2014-04-08 Stéphane Brull , Pierre Degond , Fabrice Deluzet , Alexandre Mouton

In this paper we study a reaction diffusion problem with anisotropic diffusion and mixed Dirichlet-Neumann boundary conditions on the boundary of the domain. First, we prove that the parabolic problem has a unique positive, bounded…

Analysis of PDEs · Mathematics 2025-04-11 Serena Benigno

For static reductions of isotropic and anisotropic Magnetohydrodynamics plasma equilibrium models, a complete classification of admitted point symmetries and conservation laws up to first order is presented. It is shown that the symmetry…

Mathematical Physics · Physics 2009-11-13 Alexei F. Cheviakov , Stephen C. Anco

We present a novel solver technique for the anisotropic heat flux equation, aimed at the high level of anisotropy seen in magnetic confinement fusion plasmas. Such problems pose two major challenges: (i) discretization accuracy and (ii)…

Numerical Analysis · Mathematics 2024-03-15 Golo A. Wimmer , Ben S. Southworth , Thomas J. Gregory , Xian-Zhu Tang