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In many astrophysical plasmas, the Coulomb collision is insufficient to maintain an isotropic temperature, and the system is driven to the anisotropic regime. In this case, magnetohydrodynamic (MHD) models with anisotropic pressure are…

Plasma Physics · Physics 2023-08-09 Hongyang Luo , John G. Lyon , Binzheng Zhang

This work aims to describe a mathematical model and a numerical method to simulate a thin anisotropic composite membrane moving and deforming in 3D space under a dynamic load of an arbitrary time and space profile. The model and the method…

Numerical Analysis · Mathematics 2020-07-24 Vitalii Aksenov , Alexey Vasyukov , Igor Petrov

The aim is to justify rigorously the so-called reduced magnetohydrodynamic model (abbreviated as RMHD), which is widely used in fusion, space and astrophysical plasmas. Motivated by physics, the focus is on plasmas that are simultaneously…

Analysis of PDEs · Mathematics 2025-06-30 Nicolas Besse , Christophe Cheverry

We describe a new theoretical and numerical framework of the magnetohydrodynamic simulation incorporated with an anisotropic pressure tensor, which can play an important role in a collisionless plasma. A classical approach to handle the…

Plasma Physics · Physics 2016-11-23 Kota Hirabayashi , Masahiro Hoshino , Takanobu Amano

We study the problem $-\Delta u = \gamma$, where $\gamma$ is a singular measure, with support on a curve or a point. We prove that optimal rates of convergence for the finite element method can be obtained using properly graded meshes. In…

Numerical Analysis · Mathematics 2017-06-29 Ignacio Ojea

A 2D nonlinear model for the electrical potential in the edge plasma in a tokamak generates a stiff problem due to the low resistivity in the direction parallel to the magnetic field lines. An asymptotic-preserving method based on a…

Numerical Analysis · Mathematics 2014-07-07 Philippe Angot , Thomas Auphan , Olivier Guès

This paper concerns the reconstruction of an anisotropic conductivity tensor in an elliptic second-order equation from knowledge of the so-called power density functionals. This problem finds applications in several coupled-physics medical…

Analysis of PDEs · Mathematics 2013-02-15 Guillaume Bal , Chenxi Guo , Francois Monard

A new anisotropic mesh adaptation strategy for finite element solution of elliptic differential equations is presented. It generates anisotropic adaptive meshes as quasi-uniform ones in some metric space, with the metric tensor being…

Numerical Analysis · Mathematics 2015-03-19 Xiaobo Yin , Hehu Xie

Non-ideal fluids are likely to be affected by the occurrence of pressure anisotropy effects, whose understanding for relativistic systems requires knowledge of the energy-momentum tensor. In this paper the case of magnetized jet plasmas at…

Plasma Physics · Physics 2023-06-22 Claudio Cremaschini

The aim of this work is to show an abstract framework to analyze the numerical approximation by using a finite element method in space and a Backward-Euler scheme in time of a family of degenerate parabolic problems. We deduce sufficient…

Numerical Analysis · Mathematics 2020-06-01 Ramiro Acevedo , Chrisitan Gómez , Bibiana López-Rodríguez

The paper presents a system of nonlinear Lorentz-invariant equations. The behavior of their localized solutions is analogous to the processes of formation of azimuthal-anisotropic elliptical flows of quark-gluon plasma and hadron jets. In…

High Energy Physics - Phenomenology · Physics 2020-12-15 R. K. Salimov , T. R. Salimov

We present a method to compute the magnetic moment of a bulk, finite-size, three-dimensional, anisotropic superconductor. Our numerically implemented perturbative procedure is based on a solution of the nonlinear Maxwell- London equations,…

Superconductivity · Physics 2009-10-30 Igor Zutic , Oriol T. Valls

We propose an adaptive finite element algorithm to approximate solutions of elliptic problems whose forcing data is locally defined and is approximated by regularization (or mollification). We show that the energy error decay is…

Numerical Analysis · Mathematics 2022-07-26 Luca Heltai , Wenyu Lei

The plasma of quarks and gluons created in ultrarelativistic heavy-ion collisions turns out to be paramagnetic. In the presence of a background magnetic field, this paramagnetism thus leads to a pressure anisotropy, similar to anisotropies…

Nuclear Theory · Physics 2019-10-02 N. Sadooghi , S. M. A. Tabatabaee

Adaptive multilevel finite element methods are developed and analyzed for certain elliptic systems arising in geometric analysis and general relativity. This class of nonlinear elliptic systems of tensor equations on manifolds is first…

Numerical Analysis · Mathematics 2010-01-12 Michael Holst

We present and analyse a numerical framework for the approximation of nonlinear degenerate elliptic equations of the Stefan or porous medium types. This framework is based on piecewise constant approximations for the functions, which we…

Numerical Analysis · Mathematics 2019-12-20 Jerome Droniou , Robert Eymard

We are concerned with the well-posedness of linear elliptic systems posed on $\mathbb{R}^d$. The concrete problem of interest, for which we require this theory, arises from the linearization of the equations of anisotropic finite…

Analysis of PDEs · Mathematics 2012-04-16 Christoph Ortner , Endre Suli

We consider the numerical approximation of the inertial Landau-Lifshitz-Gilbert equation (iLLG), which describes the dynamics of the magnetization in ferromagnetic materials at subpicosecond time scales. We propose and analyze two fully…

Numerical Analysis · Mathematics 2021-10-07 Michele Ruggeri

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 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