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Related papers: RAMSES-RT: Radiation hydrodynamics in the cosmolog…

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We study the Richtmyer--Meshkov (RM) instability of a relativistic perfect fluid by means of high order numerical simulations with adaptive mesh refinement (AMR). The numerical scheme adopts a finite volume Weighted Essentially…

Fluid Dynamics · Physics 2014-11-04 Olindo Zanotti , Michael Dumbser

We introduce a new code for computing time-dependent continuum radiative transfer and non-equilibrium ionization states in static density fields with periodic boundaries. Our code solves the moments of the radiative transfer equation,…

Astrophysics · Physics 2009-11-13 K. Finlator , F. Ozel , R. Dave

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

We present the extension of GR-Athena++ to general-relativistic magnetohydrodynamics (GRMHD) for applications to neutron star spacetimes. The new solver couples the constrained transport implementation of Athena++ to the Z4c formulation of…

General Relativity and Quantum Cosmology · Physics 2023-11-10 William Cook , Boris Daszuta , Jacob Fields , Peter Hammond , Simone Albanesi , Francesco Zappa , Sebastiano Bernuzzi , David Radice

We present a new method for the numerical solution of the radiative-transfer equation (RTE) in multidimensional scenarios commonly encountered in computational astrophysics. The method is based on the direct solution of the Boltzmann…

Computational Physics · Physics 2020-10-06 L. R. Weih , A. Gabbana , D. Simeoni , L. Rezzolla , S. Succi , R. Tripiccione

When solving the time-dependent radiative transport equation (RTE), implicit time discretization is often employed for its robustness and stability. This results in a sequence of steady-state RTEs with identical cross-sections but varying…

Numerical Analysis · Mathematics 2026-04-24 Qinchen Song , Lei Zhang , Min Tang

Observational efforts to image the immediate environment of a black hole at the scale of the event horizon benefit from the development of efficient imaging codes that are capable of producing synthetic data, which may be compared with…

High Energy Astrophysical Phenomena · Physics 2018-09-06 Thomas Bronzwaer , Jordy Davelaar , Ziri Younsi , Monika Mościbrodzka , Heino Falcke , Michael Kramer , Luciano Rezzolla

We present a new general relativistic magnetohydrodynamics (GRMHD) code integrated into the Athena++ framework. Improving upon the techniques used in most GRMHD codes, ours allows the use of advanced, less diffusive Riemann solvers, in…

High Energy Astrophysical Phenomena · Physics 2016-08-17 Christopher J. White , James M. Stone , Charles F. Gammie

We describe the structure and implementation of a radiation hydrodynamic solver for MANGA, the moving-mesh hydrodynamics module of the large-scale parallel code, Charm N-body GrAvity solver (ChaNGa). We solve the equations of time dependent…

Instrumentation and Methods for Astrophysics · Physics 2020-03-04 Philip Chang , Shane W. Davis , Yan-Fei Jiang

Methods to solve the relativistic hydrodynamic equations are a key computational kernel in a large number of astrophysics simulations and are crucial to understanding the electromagnetic signals that originate from the merger of…

Instrumentation and Methods for Astrophysics · Physics 2015-12-02 Jackson DeBuhr , Bo Zhang , Matthew Anderson , David Neilsen , Eric W. Hirschmann

Numerical evolution of the spherically symmetric, massive Klein-Gordon field is presented using a new adaptive mesh refinement (AMR) code with fourth order discretization in space and time, along with compactification in space. The system…

High Energy Physics - Theory · Physics 2009-11-11 Peter Csizmadia

Gravitational instabilities naturally give rise to multi-scale structure, which is difficult for traditional Eulerian hydrodynamic methods to accurately evolve. This can be circumvented by adaptively adding resolution (in the form of…

Astrophysics · Physics 2007-05-23 G. L. Bryan , M. L. Norman

In this work we develop an approach for a molecular hydrogen ion (H2+) in the Born-Oppenheimer approximation while exposed to intense short-pulse radiation. Our starting point is the R-Matrix incorporating Time (RMT) formulation for atomic…

Atomic Physics · Physics 2016-01-01 Cathal Ó Broin , Lampros A. A. Nikolopoulos

The problem of the resolution of turbulent flows in adaptive mesh refinement (AMR) simulations is investigated by means of 3D hydrodynamical simulations in an idealised setup, representing a moving subcluster during a merger event. AMR…

Astrophysics · Physics 2009-11-13 L. Iapichino , J. Adamek , W. Schmidt , J. C. Niemeyer

High-order solvers for compressible flows are vital in scientific applications. Adaptive mesh refinement (AMR) is a key technique for reducing computational cost by concentrating resolution in regions of interest. In this work, we develop…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-08-08 Anjiang Wei , Hang Song , Mert Hidayetoglu , Elliott Slaughter , Sanjiva K. Lele , Alex Aiken

In this paper, Hamiltonian and energy preserving reduced-order models are developed for the rotating thermal shallow water equation (RTSWE) in the non-canonical Hamiltonian form with the state-dependent Poisson matrix. The high fidelity…

Numerical Analysis · Mathematics 2024-06-19 Suleyman Yildiz , Murat Uzunca , Bulent Karasozen

The characteristic decomposition for GRMHD is not known in a form useful for current numerical simulations. This prevents us from using the most accurate known computational methods, such as full-wave Riemann solvers. In this paper, we…

General Relativity and Quantum Cosmology · Physics 2025-11-19 Saul A. Teukolsky

We describe an extension of the cosmological hydrodynamics code ENZO to include the self-consistent transport of ionizing radiation modeled in the flux-limited diffusion approximation. A novel feature of our algorithm is a coupled implicit…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Michael L. Norman , Daniel R. Reynolds , Geoffrey C. So

Modeling correctly the transport of neutrinos is crucial in some astrophysical scenarios such as core-collapse supernovae and binary neutron star mergers. In this paper, we focus on the truncated-moment formalism, considering only the first…

General Relativity and Quantum Cosmology · Physics 2023-05-30 Manuel R. Izquierdo , Lorenzo Pareschi , Borja Miñano , Joan Massó , Carlos Palenzuela

We present MHDuet, an open source evolution code for general relativistic magnetohydrodynamics with neutrino transport. The code solves the full set of Einstein equations coupled to a relativistic, magnetized fluid with an M1 neutrino…

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