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In this paper, we present a high order finite difference solver for anisotropic diffusion problems based on the first-order hyperbolic system method. In particular, we demonstrate that the construction of a uniformly accurate fifth-order…

Computational Physics · Physics 2019-07-30 Amareshwara Sainadh Chamarthi , Hiroaki Nishikawa , Kimiya Komurasaki

In partially ionised plasmas, the magnetic field can become decoupled from the neutral gas and diffuse through it in a process known as ambipolar diffusion. Although ambipolar diffusion has been implemented in several grid codes, we here…

Solar and Stellar Astrophysics · Physics 2015-06-22 James Wurster , Daniel J. Price , Ben A. Ayliffe

Collisionless electron-ion shocks are fundamental to astrophysical plasmas, yet their behavior in strong magnetic fields remains poorly understood. Using Particle-in-Cell (PIC) simulations with the SHARP-1D3V code, we investigate the role…

Solar and Stellar Astrophysics · Physics 2025-11-17 Mohamad Shalaby , Antoine Bret , Federico Fraschetti

Simple finite differencing of the anisotropic diffusion equation, where diffusion is only along a given direction, does not ensure that the numerically calculated heat fluxes are in the correct direction. This can lead to negative…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Prateek Sharma , Gregory W. Hammett

The present paper introduces an efficient and accurate numerical scheme for the solution of a highly anisotropic elliptic equation, the anisotropy direction being given by a variable vector field. This scheme is based on an asymptotic…

Numerical Analysis · Mathematics 2014-04-08 Pierre Degond , Fabrice Deluzet , Alexei Lozinski , Jacek Narski , Claudia Negulescu

We briefly review the recent developments in magnetohydrodynamics, which in particular deal with the evolution of magnetic fields in turbulent plasmas. We especially emphasize (i) the necessity of renormalizing equations of motion in…

Plasma Physics · Physics 2025-05-01 Amir Jafari

A new regime of fast magnetic reconnection with an out-of-plane (guide) magnetic field is reported in which the key role is played by an electron pressure anisotropy described by the Chew-Goldberger-Low gyrotropic equations of state in the…

The energy production through thermo-nuclear fusion requires the confinement of the plasma into a bounded domain. In most of the cases, such configurations are obtained by using strong magnetic fields. Several models exist for describing…

Analysis of PDEs · Mathematics 2012-07-11 Mihai Bostan

Two-fluid relativistic plasma flow equations combine the equations of relativistic hydrodynamics with Maxwell's equations for electromagnetic fields, which involve divergence constraints for the magnetic and electric fields. When developing…

Numerical Analysis · Mathematics 2025-03-27 Jaya Agnihotri , Deepak Bhoriya , Harish Kumar , Praveen Chandrashekar , Dinshaw S. Balsara

This paper is devoted to the complete convergence study of the finite-element approximation of Maxwell's equations in the case where the magnetic permeability is constant. Standard linear finite elements for the space discretization are…

Numerical Analysis · Mathematics 2020-07-06 Larisa Beilina , Vitoriano Ruas

The purpose of the present paper is to provide an overview of Asymptotic-Preserving methods for multiscale plasma simulations by addressing three singular perturbation problems. First, the quasi-neutral limit of fluid and kinetic models is…

Plasma Physics · Physics 2017-04-05 Pierre Degond , Fabrice Deluzet

Diffusive transport processes in magnetized plasmas are highly anisotropic, with fast parallel transport along the magnetic field lines sometimes faster than perpendicular transport by orders of magnitude. This constitutes a major challenge…

Plasma Physics · Physics 2024-12-04 Federico D. Halpern , Min-Gu Yoo , Brendan Lyons , Juan Diego Colmenares

The Discrete Particle Method (DPM) is used to model granular flows down an inclined chute. We observe three major regimes: static piles, steady uniform flows and accelerating flows. For flows over a smooth base, other (quasi-steady) regimes…

Soft Condensed Matter · Physics 2011-08-26 Thomas Weinhart , Anthony Thornton , Stefan Luding , Onno Bokhove

Solutions of the linearized Vlasov-Poisson equations for the electric field radiated by a time varying point charge in a three-dimensional, unbounded, spatially homogeneous plasma with a uniform background magnetic field and a uniform…

Plasma Physics · Physics 2015-06-04 John J. Podesta

A one-dimensional chain of elongated anisotropic magnetic islands on a nonmagnetic substrate with dipolar interactions and an applied magnetic field transverse to the chain is considered. With the long axes of the islands perpendicular to…

Mesoscale and Nanoscale Physics · Physics 2026-03-20 G. M. Wysin

We propose and analyze a class of particle methods for the Vlasov equation with a strong external magnetic field in a torus configuration. In this regime, the time step can be subject to stability constraints related to the smallness of…

Numerical Analysis · Mathematics 2023-05-16 Francis Filbet , Luis Miguel Miguel Rodrigues

We construct fully three-dimensional (3D) equilibria with pressure anisotropy and closed, nested toroidal magnetic surfaces that are strongly asymmetric in the toroidal direction by applying a sinusoidal perturbation to the axisymmetric…

Plasma Physics · Physics 2026-03-24 D. A. Kaltsas , A. I. Kuiroukidis , G. N. Throumoulopoulos

We examine the effect of uniform ambient magnetic fields on the evolution of supernova-driven blast waves into a homogeneous ambient ISM in thermal equilibrium. Using the Pencil Code we simulate high resolution nonideal magnetohydrodynamic…

High Energy Astrophysical Phenomena · Physics 2019-09-24 Cetin Can Evirgen , Frederick Gent

We show that in a neutral magnetized plasma there exist microscopic oscillatory modes, with wavelengths of the order of magnitude of the mean interparticle distance, which become unstable when the electron density exceeds a limit…

Plasma Physics · Physics 2010-06-24 M. Marino , M. Zuin , A. Carati , E. Martines , L. Galgani

We consider various sets of Vlasov-Fokker-Planck equations modeling the dynamics of charged particles in a plasma under the effect of a strong magnetic field. For each of them in a regime where the strength of the magnetic field is…

Analysis of PDEs · Mathematics 2020-06-30 Maxime Herda , Luis Miguel Rodrigues