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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 find two families of analytic solutions to the ideal magnetohydrodynamics (iMHD) equations, in a class of 4-dimensional (4D) curved spacetimes. The plasma current is null, and as a result, the stress-energy tensor of the plasma itself…

General Relativity and Quantum Cosmology · Physics 2016-05-31 Yi-Zen Chu , Vitaly Vanchurin

We study a 1D geometry of a plasma confined between two conducting floating walls with applications to laboratory plasmas. These plasmas are characterized by a quasi-neutral bulk that is joined to the wall by a thin boundary layer called…

Numerical Analysis · Mathematics 2023-01-02 Louis Reboul , Marc Massot , Alejandro Alvarez Laguna

Many important problems in astrophysics, space physics, and geophysics involve flows of (possibly ionized) gases in the vicinity of a spherical object, such as a star or planet. The geometry of such a system naturally favors numerical…

Computational Physics · Physics 2020-04-01 V. Florinski , D. S. Balsara , S. Garain , K. F. Gurski

Four different approximate approaches used to model the stressing of coronal magnetic fields due to an imposed photospheric motion are compared with each other and the results from a full time-dependent magnetohydrodynamic (MHD) code. The…

Solar and Stellar Astrophysics · Physics 2018-02-28 E. E. Goldstraw , A. W. Hood , P. K. Browning , P. J. Cargill

This paper formulates a new particle-in-cell method for the Vlasov-Maxwell system. Under the Lorenz gauge condition, Maxwell's equations for the electromagnetic fields can be written as a collection of scalar and vector wave equations. The…

Plasma Physics · Physics 2024-01-18 Andrew J. Christlieb , William A. Sands , Stephen White

The accurate modelling of astrophysical scenarios involving compact objects and magnetic fields, such as the collapse of rotating magnetized stars to black holes or the phenomenology of gamma-ray bursts, requires the solution of the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 B. Giacomazzo , L. Rezzolla

In toroidally confined plasmas, the Grad-Shafranov equation, in general a non-linear PDE, describes the hydromagnetic equilibrium of the system. This equation becomes linear when the kinetic pressure is proportional to the poloidal magnetic…

Plasma Physics · Physics 2015-06-22 D. Ciro , I. L. Caldas

Coulomb collisions in particle simulations for weakly coupled plasmas are modeled by the Landau-Fokker-Planck equation, which is typically solved by Monte-Carlo (MC) methods. One of the main disadvantages of MC is the timestep accuracy…

Computational Physics · Physics 2025-01-03 G. Chen , A. J. Stanier , L. Chacón , S. E. Anderson , B. Philip

We present an improved version of the ECHO-QGP numerical code, which self-consistently includes for the first time the effects of electromagnetic fields within the framework of relativistic magnetohydrodynamics (RMHD). We discuss results of…

High Energy Physics - Phenomenology · Physics 2017-01-12 Gabriele Inghirami , Luca Del Zanna , Andrea Beraudo , Mohsen Haddadi Moghaddam , Francesco Becattini , Marcus Bleicher

The equations of general relativistic magnetohydrodynamics (GRMHD) have become the standard mathematical framework for modeling high-energy plasmas in curved spacetimes. However, the fragility of the primitive variable reconstruction…

General Relativity and Quantum Cosmology · Physics 2025-10-31 Jonathan Gorard , James Juno , Ammar Hakim

By means of magnetohydrodynamic equations in a non relativistic multi fluid framework, we study the behavior of small amplitude perturbations in cold Quark Gluon Plasmas (QGP). Magnetohydrodynamic equations, along with the QGP equation of…

High Energy Physics - Theory · Physics 2018-01-01 Azam Ghaani , Kurosh Javidan

The paper presents the solutions for the two-beam reduction of the dense soliton gas equations (or Born-Infeld equation) obtained by analytical and numerical methods. The method proposed by the authors is used. This method allows to reduce…

Fluid Dynamics · Physics 2015-12-22 E. V. Shiryaeva , M. Yu. Zhukov

We present three-dimensional solutions of the magnetohydrostatic equations in the co-rotating frame of reference outside a magnetized rigidly rotating cylinder. We make no symmetry assumption for the magnetic field, but to be able to make…

Earth and Planetary Astrophysics · Physics 2009-11-30 Thomas Neukirch

This paper is devoted to the numerical approximation of a degenerate anisotropic elliptic problem. The numerical method is designed for arbitrary space-dependent anisotropy directions and does not require any specially adapted coordinate…

Numerical Analysis · Mathematics 2014-04-08 Stéphane Brull , Pierre Degond , Fabrice Deluzet

This contribution deals with the modeling of collisional multicomponent magnetized plasmas in thermal and chemical nonequilibrium aiming at simulating and predicting magnetic reconnections in the chromosphere of the sun. We focus on the…

Numerical Analysis · Mathematics 2021-06-01 Quentin Wargnier , Sylvain Faure , Benjamin Graille , Thierry Magin , Marc Massot

A necessary and sufficient set of conditions for a quasisymmetric magnetic field in the form of constraint equations is derived from first principles. Without any assumption regarding the magnetohydrodynamic (MHD) equilibrium of the plasma,…

Plasma Physics · Physics 2020-06-24 Eduardo Rodriguez , Per Helander , Amitava Bhattacharjee

We present a detailed guide to advanced collisionless fluid models that incorporate kinetic effects into the fluid framework, and that are much closer to the collisionless kinetic description than traditional magnetohydrodynamics. Such…

The Vlasov-Maxwell equations provide kinetic simulations of collisionless plasmas, but numerically solving them on classical computers is often impractical. This is due to the computational resource constraints imposed by the time evolution…

A new approach using a hyperbolic-equation system (HES) is proposed to solve for the electron fluids in quasi-neutral plasmas. The HES approach avoids treatments of cross-diffusion terms which cause numerical instabilities in conventional…

Computational Physics · Physics 2017-12-11 R. Kawashima , K. Komurasaki , T. Schoenherr