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The diffusion limit of the linear Boltzmann equation with a strong magnetic field is performed. The giration period of particles around the magnetic field is assumed to be much smaller than the collision relaxation time which is supposed to…

Analysis of PDEs · Mathematics 2010-05-31 Naoufel Ben Abdallah , Raymond El Hajj

We consider a stochastic differential equation for a charged particle in a stochastic magnetic field, known as A-Langevin equation. The solution of the equation is found, and the Lagrange velocity correlation function is calculated in…

Chaotic Dynamics · Physics 2007-05-23 D. Lesnik , S. Gordienko , M. Neuer , K. -H. Spatschek

A moving mesh finite difference method based on the moving mesh partial differential equation is proposed for the numerical solution of the 2T model for multi-material, non-equilibrium radiation diffusion equations. The model involves…

Numerical Analysis · Mathematics 2020-04-20 Xiaobo Yang , Weizhang Huang , Jianxian Qiu

We solve the anisotropic diffusion equation in 2D, where the dominant direction of diffusion is defined by a vector field which does not conform to a Cartesian grid. Our method uses operator splitting to separate the diffusion perpendicular…

Numerical Analysis · Mathematics 2023-03-29 Dean Muir , Kenneth Duru , Matthew Hole , Stuart Hudson

A probabilistic method is derived for solution of ohmic circuit problems. It is compared to the standard approach, which is construction and solution of a set of coupled, linear equations manifesting Kirchhoff's laws. An example is made of…

Statistical Mechanics · Physics 2019-06-26 Clinton DeW. Van Siclen

We consider the long time behavior of solutions to the magnetohydrodynamics equations in two and three spatial dimensions. It is shown that in the absence of magnetic diffusion, if strong bounded solutions were to exist their energy cannot…

Analysis of PDEs · Mathematics 2007-05-23 Ruben Agapito , Maria Schonbek

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

We present a robust and accurate numerical method for the anisotropic diffusion equation in curvilinear coordinates. This study extends the recent work [Muir et al., Computer Physics Communications, 2025] for solving the anisotropic…

Numerical Analysis · Mathematics 2026-04-23 Dean Muir , Kenneth Duru , Stuart Hudson , Matthew Hole

We present a novel numerical method for solving the anisotropic diffusion equation in magnetic fields confined to a periodic box which is accurate and provably stable. We derive energy estimates of the solution of the continuous initial…

Numerical Analysis · Mathematics 2025-02-13 Dean Muir , Kenneth Duru , Matthew Hole , Stuart Hudson

We provide a stochastic fractional diffusion equation description of energy transport through a finite one-dimensional chain of harmonic oscillators with stochastic momentum exchange and connected to Langevian type heat baths at the…

Statistical Mechanics · Physics 2019-05-22 Aritra Kundu , Cédric Bernardin , Keji Saito , Anupam Kundu , Abhishek Dhar

We expand the off-resonant scattering theory for particle diffusion in magnetized current filaments that can be typically compared to astrophysical jets, including active galactic nucleus jets. In a high plasma beta region where the…

Astrophysics · Physics 2009-11-13 Mitsuru Honda , Yasuko S. Honda

MIF approaches, such as the MagLIF experiment, use magnetic fields in dense plasma to suppress cross-field thermal conduction, attempting to reduce heat losses and trap alpha particles to achieve ignition. However, the magnetic field can…

Plasma Physics · Physics 2022-04-06 G. Farrow , G. Kagan , J. P. Chittenden

We present a novel artificial diffusion method to circumvent the instabilities associated with the standard finite element approximation of convection-diffusion equations. Motivated by the micromorphic approach, we introduce an auxiliary…

Numerical Analysis · Mathematics 2025-06-19 Soheil Firooz , B. Daya Reddy , Paul Steinmann

A photon or neutrino gas--semi-contained by a baryonic species through scattering--comprises a rather peculiar MHD fluid where the magnetic field is truly frozen only to the co-moving volume associated with the mass density. Although…

Astrophysics · Physics 2007-05-23 Rafael A. Araya-Gochez , Ethan Vishniac

Nonlinear diffusion equations of spectral transfer are systematically derived for anisotropic magnetohydrodynamics in the regime of wave turbulence. The background of the analysis is the asymptotic Alfv\'en wave turbulence equations from…

Solar and Stellar Astrophysics · Physics 2015-05-19 Sebastien Galtier , Eric Buchlin

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

Convection-diffusion equations arise in a variety of applications such as particle transport, electromagnetics, and magnetohydrodynamics. Simulation of the convection-dominated regime for these problems, even with high-fidelity techniques,…

Numerical Analysis · Mathematics 2023-05-24 James H. Adler , Casey Cavanaugh , Xiaozhe Hu , Andy Huang , Nathaniel Trask

We derive an explicit representation of the fundamental solution to the heat equation in a half-space of ${\mathbb R}^N$ with a diffusive dynamical boundary condition, and establish sharp pointwise upper and lower bounds. We also…

Analysis of PDEs · Mathematics 2026-04-02 Kazuhiro Ishige , Sho Katayama , Tatsuki Kawakami

Stochasticity of magnetic field lines is important for particle transport properties. Magnetic field lines separate faster than diffusively in turbulent plasma, which is called superdiffusion. We discovered that this superdiffusion is…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Andrey Beresnyak

Astrophysical plasmas are subject to a tight connection between magnetic fields and the diffusion of particles, which leads to an anisotropic transport of energy. Under the fluid assumption, this effect can be reduced to an…

Astrophysics of Galaxies · Physics 2016-01-13 Yohan Dubois , Benoît Commerçon
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