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Related papers: Approximate Riemann Solvers for the Cosmic Ray Mag…

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In this paper, we develop a new method for magnetohydrodynamics (MHD) using smoothed particle hydrodynamics (SPH). To describe MHD shocks accurately, the Godunov method is applied to SPH instead of artificial dissipation terms. In the…

Astrophysics of Galaxies · Physics 2015-05-28 Kazunari Iwasaki , Shu-ichiro Inutsuka

We construct a relativistic resistive magneto-hydrodynamic (RRMHD) numerical simulation code for high-energy heavy-ion collisions. We split the system of differential equations into two parts, a non-stiff and a stiff part. For the non-stiff…

Nuclear Theory · Physics 2023-04-05 Kouki Nakamura , Takahiro Miyoshi , Chiho Nonaka , Hiroyuki R. Takahashi

Multidimensional shock-capturing numerical schemes for special relativistic hydrodynamics (RHD) are computationally more expensive than their correspondent Euler versions, due to the nonlinear relations between conservative and primitive…

Astrophysics · Physics 2009-11-07 L. Del Zanna , N. Bucciantini

Numerical solutions of the cosmic-ray (CR) magneto-hydrodynamic equations are dogged by a powerful numerical instability, which arises from the constraint that CRs can only stream down their gradient. The standard cure is to regularize by…

High Energy Astrophysical Phenomena · Physics 2018-03-16 Yan-Fei Jiang , Peng Oh

Approximate Riemann solvers are widely used for solving hyperbolic conservation laws, including those of magnetohydrodynamics (MHD). However, due to the nonlinearity and complexity of MHD, obtaining accurate and robust numerical solutions…

Fluid Dynamics · Physics 2025-11-25 Fan Zhang , Andrea Lani , Stefaan Poedts

Cosmic rays (CRs) are an important source of feedback in a variety of astrophysical contexts. Magneto-hydrodynamical (MHD) simulations treating CRs as a fluid have shown that how their feedback operates is strongly dependent on their…

Astrophysics of Galaxies · Physics 2025-09-25 Joki Rosdahl , Yohan Dubois , Benoit Commercon , Nimatou Diallo , Nai Chieh Lin , Alexandre Marcowith

Cosmic rays (CRs) play an important role in many astrophysical systems. Acting on plasma scales to galactic environments, CRs are usually modeled as a fluid, using the CR energy density as the evolving quantity. This method comes with the…

High Energy Astrophysical Phenomena · Physics 2023-01-04 Matthias Weber , Timon Thomas , Christoph Pfrommer

In this paper we present a novel pressure-based semi-implicit finite volume solver for the equations of compressible ideal, viscous and resistive magnetohydrodynamics (MHD). The new method is conservative for mass, momentum and total energy…

Numerical Analysis · Mathematics 2018-12-26 Michael Dumbser , Dinshaw S. Balsara , Maurizio Tavelli , Francesco Fambri

We present a new numerical method of special relativistic resistive magnetohydrodynamics with scalar resistivity that can treat a range of phenomena, from nonrelativistic to relativistic (shock, contact discontinuity, and Alfv\'en wave).…

High Energy Astrophysical Phenomena · Physics 2015-05-28 Makoto Takamoto , Tsuyoshi Inoue

We have written and tested a new general relativistic magnetohydrodynamics (GRMHD) code, capable of evolving MHD fluids in dynamical spacetimes with adaptive-mesh refinement (AMR). Our code solves the Einstein-Maxwell-MHD system of coupled…

High Energy Astrophysical Phenomena · Physics 2010-10-27 Zachariah B. Etienne , Yuk Tung Liu , Stuart L. Shapiro

We compare a particular selection of approximate solutions of the Riemann problem in the context of ideal relativistic magnetohydrodynamics. In particular, we focus on Riemann solvers not requiring a full eigenvector structure. Such solvers…

High Energy Astrophysical Phenomena · Physics 2021-12-23 Giancarlo Mattia , Andrea Mignone

In this paper we present a full general relativistic one-dimensional hydro-code which incorporates a modern high-resolution shock-capturing algorithm, with an approximate Riemann solver, for the correct modelling of formation and…

Astrophysics · Physics 2009-10-28 Jose V. Romero , Jose M. Ibanez , Jose M. Marti , Juan A. Miralles

We present a new numerical code which solves the general relativistic magneto-hydrodynamics (GRMHD) equations coupled to the Einstein equations for the evolution of a dynamical spacetime within the conformally-flat approximation. This code…

Astrophysics · Physics 2009-11-13 Pablo Cerdá-Durán , José A. Font , Luis Antón , Ewald Müller

We discuss new methods to integrate the cosmic ray (CR) evolution equations coupled to magneto-hydrodynamics (MHD) on an unstructured moving mesh, as realised in the massively parallel AREPO code for cosmological simulations. We account for…

Astrophysics of Galaxies · Physics 2017-01-11 C. Pfrommer , R. Pakmor , K. Schaal , C. M. Simpson , V. Springel

We describe a novel Godunov-type numerical method for solving the equations of resistive relativistic magnetohydrodynamics. In the proposed approach, the spatial components of both magnetic and electric fields are located at zone interfaces…

Computational Physics · Physics 2019-05-01 A. Mignone , G. Mattia , G. Bodo , L. Del Zanna

In this paper, we present an approach to solving the Riemann problem in one-dimensional relativistic hydrodynamics, where the most computationally expensive steps of the exact solver are replaced by compact, highly specialized neural…

General Relativity and Quantum Cosmology · Physics 2025-05-27 Carlo Musolino

In this chapter, we aim at presenting the basic techniques necessary to go beyond the widely accepted paradigm of second-order numerics. We specifically focus on finite-volume schemes for hyperbolic conservation laws occuring in fluid…

Numerical Analysis · Mathematics 2024-07-29 Jean-Mathieu Teissier , Wolf-Christian Müller

The relativistic magnetohydrodynamics (RMHD) set of equations has recently seen increased use in astrophysical computations. Even so, RMHD codes remain fragile. The reconstruction can sometimes yield superluminal velocities in certain parts…

High Energy Astrophysical Phenomena · Physics 2016-03-23 Dinshaw S. Balsara , Jinho Kim

Higher order finite volume schemes for magnetohydrodynamics (MHD) and relativistic magnetohydrodynamics (RMHD) are very valuable because they allow us to carry out astrophysical simulations with very high accuracy. However, astrophysical…

Instrumentation and Methods for Astrophysics · Physics 2025-06-16 Dinshaw S. Balsara , Deepak Bhoriya , Chetan Singh , Harish Kumar , Roger Käppeli , Federico Gatti

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