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Despite the success of the combination of conservative schemes and staggered constrained transport algorithms in the last fifteen years, the accurate description of highly magnetized, relativistic flows with strong shocks represents still a…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 José M. Martí

Generalising the Elsasser variables, we introduce the Q-variables. These are more flexible than the Elsasser variables, because they also allow to track waves with phase speeds different than the Alfven speed. We rewrite the MHD equations…

Plasma Physics · Physics 2024-01-17 Tom Van Doorsselaere , Norbert Magyar , M. Valeria Sieyra , Marcel Goossens

Fully adaptive computations of the resistive magnetohydrodynamic (MHD) equations are presented in two and three space dimensions using a finite volume discretization on locally refined dyadic grids. Divergence cleaning is used to control…

Numerical Analysis · Mathematics 2021-02-24 Anna Karina Fontes Gomes , Margarete Oliveira Domingues , Odim Mendes , Kai Schneider

In gravitationally stratified fluids, length scales are normally much greater in the horizontal direction than in the vertical one. When modelling these fluids it can be advantageous to use the hydrostatic approximation, which filters out…

Instrumentation and Methods for Astrophysics · Physics 2013-07-29 Jonathan Braithwaite , Yuri Cavecchi

A high-fidelity finite volume scheme based on the BVD (boundary variation diminishing) concept is proposed in this study to solve the ideal magnetohydrodynamics (MHD) equations. A hybrid spatial reconstruction profile, consisting of a…

Fluid Dynamics · Physics 2024-04-24 Pan Chenxi , Song Sheng , Chen Chungang , Li Xingliang , Shen Xueshun , Xiao Feng

Deep learning models have significantly improved the visual quality and accuracy on compressive sensing recovery. In this paper, we propose an algorithm for signal reconstruction from compressed measurements with image priors captured by a…

Machine Learning · Computer Science 2020-03-20 Shaojie Xu , Sihan Zeng , Justin Romberg

We introduce a mathematical model for ultrasound modulated optical tomography and present a simple reconstruction scheme for recovering the spatially varying optical absorption coefficient from scanning measurements with narrowly focused…

Analysis of PDEs · Mathematics 2010-04-12 Moritz Allmaras , Wolfgang Bangerth

We develop a new second-order unstaggered path-conservative central-upwind (PCCU) scheme for ideal and shallow water magnetohydrodynamics (MHD) equations. The new scheme possesses several important properties: it locally preserves the…

Numerical Analysis · Mathematics 2022-12-07 Alina Chertock , Alexander Kurganov , Michael Redle , Kailiang Wu

We present an adaptive-order positivity-preserving conservative finite-difference scheme that allows a high-order solution away from shocks and discontinuities while guaranteeing positivity and robustness at discontinuities. This is…

We present the implementation of a three-dimensional, second order accurate Godunov-type algorithm for magneto-hydrodynamic (MHD), in the adaptive-mesh-refinement (AMR) cosmological code {\tt CHARM}. The algorithm is based on the full…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Francesco Miniati , Daniel F. Martin

We construct magnetohydrodynamic (MHD) similarity rebound shocks joining `quasi-static' asymptotic solutions around the central degenerate core to explore an MHD model for the evolution of random magnetic field in supernova explosions. This…

Astrophysics · Physics 2009-06-23 Yu-Qing Lou , Wei-Gang Wang

Plasmoid structures in fast reconnection in low-beta plasmas are investigated by two-dimensional magnetohydrodynamic simulations. A high-resolution shock-capturing code enables us to explore a variety of shock structures: vertical slow…

Space Physics · Physics 2014-10-14 Seiji Zenitani , Takahiro Miyoshi

In this paper we propose a novel thermodynamically compatible finite volume scheme for the numerical solution of the equations of magnetohydrodynamics (MHD) in one and two space dimensions. As shown by Godunov in 1972, the MHD system can be…

Numerical Analysis · Mathematics 2023-01-23 Saray Busto , Michael Dumbser

We present a full investigation into shock wave profile description using hydrodynamics models. We identified constitutive equations that provide better agreement for all parameters involved in testing hydrodynamic equations for the…

Fluid Dynamics · Physics 2021-10-04 M. H. Lakshminarayana Reddy , S. Kokou Dadzie

In this paper, an energy-consistent finite difference scheme for the compressible hydrodynamic and magnetohydrodynamic (MHD) equations is introduced. For the compressible magnetohydrodynamics, an energy-consistent finite difference…

Computational Physics · Physics 2021-04-07 Haruhisa Iijima

This letter announces and summarizes results obtained in arXiv:1111.5051 and considers several natural extensions. The aforementioned paper proposes a procedure to reconstruct coefficients in a second-order, scalar, elliptic equation from…

Analysis of PDEs · Mathematics 2012-03-07 Guillaume Bal , Gunther Uhlmann

Recent advances in understanding of the basic properties of compressible Magnetohydrodynamic (MHD) turbulence call for revisions of some of the generally accepted concepts. First, MHD turbulence is not so messy as it is usually believed. In…

Astrophysics · Physics 2009-11-10 A. Lazarian , J. Cho

In this paper we show how a Lagrangian variational principle can be used to derive the SPMHD (smoothed particle magnetohydrodynamics) equations for ideal MHD. We also consider the effect of a variable smoothing length in the SPH kernels…

Astrophysics · Physics 2009-11-10 D. J. Price , J. J. Monaghan

Reduced magnetohydrodynamics is a simplified set of magnetohydrodynamics equations with applications to both fusion and astrophysical plasmas, possessing a noncanonical Hamiltonian structure and consequently a number of conserved…

Computational Physics · Physics 2017-10-05 Michael Kraus , Emanuele Tassi , Daniela Grasso

We describe a numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference scheme on an Eulerian grid, called the Total Variation Diminishing (TVD) scheme, which is a…

Astrophysics · Physics 2009-10-22 Dongsu Ryu , T. W. Jones