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Discretized numerical simulations are a powerful tool for investigation of nonlinear MHD turbulence in accretion disks. However, confidence in their quantitative predictions requires a demonstration that further refinement of the spatial…

High Energy Astrophysical Phenomena · Physics 2015-05-27 John F. Hawley , Xiaoyue Guan , Julian H. Krolik

Most numerical investigations on the role of magnetic fields in turbulent molecular clouds (MCs) are based on ideal magneto-hydrodynamics (MHD). However, MCs are weakly ionized, so that the time scale required for the magnetic field to…

Astrophysics · Physics 2009-11-13 Pak Shing Li , Christopher F. McKee , Richard I. Klein , Robert T. Fisher

What cosmic ray ionisation rate is required such that a non-ideal magnetohydrodynamics (MHD) simulation of a collapsing molecular cloud will follow the same evolutionary path as an ideal MHD simulation or as a purely hydrodynamics…

Solar and Stellar Astrophysics · Physics 2018-02-28 James Wurster , Matthew R. Bate , Daniel J. Price

Resolution studies of test problems set baselines and help define minimum resolution requirements, however, resolution studies must also be performed on scientific simulations to determine the effect of resolution on the specific scientific…

Solar and Stellar Astrophysics · Physics 2019-07-01 James Wurster , Matthew R. Bate

The aim of this paper is to improve our understanding of the heating mechanisms of the solar chromosphere via realistic three-dimensional (3D) modeling of solar magneto-convection, considering the fact that solar plasma contains a…

Solar and Stellar Astrophysics · Physics 2025-05-07 E. Khomenko , N. Vitas , M. Collados , M. Modestov

Magnetohydrodynamic (MHD) turbulence driven by the magnetorotational instability can provide diffusive transport of angular momentum in astrophysical disks, and a widely studied computational model for this process is the ideal, stratified,…

High Energy Astrophysical Phenomena · Physics 2017-05-03 Benjamin R. Ryan , Charles F. Gammie , Sebastien Fromang , Pierre Kestener

This paper explores the effects of numerical algorithms on global magnetohydrodynamics (MHD) simulations of solar wind (SW) in the inner heliosphere. To do so, we use sunRunner3D, a 3-D MHD model that employs the boundary conditions…

Solar and Stellar Astrophysics · Physics 2024-05-03 Luis Ángel de León Alanís , J. J. González-Avilés , P. Riley , M. Ben-Nun

We employ the first fully three-dimensional simulation to study the role of magnetic fields and ion-neutral friction in regulating gravitationally-driven fragmentation of molecular clouds. The cores in an initially subcritical cloud develop…

Astrophysics · Physics 2008-11-26 Takahiro Kudoh , Shantanu Basu , Youichi Ogata , Takashi Yabe

Polarisation measurements by the Event Horizon Telescope from M87$^{\ast}$ and Sgr A$^\ast$ suggest that there is a dynamically strong, ordered magnetic field, typical of what is expected of a magnetically arrested accretion disk (MAD). In…

High Energy Astrophysical Phenomena · Physics 2024-07-29 León Salas , Gibwa Musoke , Koushik Chatterjee , Sera Markoff , Oliver Porth , Matthew Liska , Bart Ripperda

Cosmic structure formation is characterized by the complex interplay between gravity, turbulence, and magnetic fields. The processes by which gravitational energy is converted into turbulent and magnetic energies, however, remain poorly…

Solar and Stellar Astrophysics · Physics 2011-03-29 Christoph Federrath , Sharanya Sur , Dominik R. G. Schleicher , Robi Banerjee , Ralf S. Klessen

We investigate the importance of ambipolar diffusion and Hall currents for high-resolution comprehensive ('realistic') photospheric simulations. To do so we extended the radiative magnetohydrodynamics code \emph{MURaM} to use the…

Solar and Stellar Astrophysics · Physics 2015-06-04 Mark C. M. Cheung , Robert H. Cameron

Axisymmetric resistive MHD simulations for radially self-similar initial conditions are performed, using the NIRVANA code. The magnetic diffusivity could occur in outflows above an accretion disk, being transferred from the underlying disk…

Solar and Stellar Astrophysics · Physics 2015-05-13 Miljenko Cemeljic , Jose Gracia , Nektarios Vlahakis , Kanaris Tsinganos

In this work we extend the non-ideal magnetohydrodynamics (MHD) solver in the moving mesh code AREPO to include the Hall effect. The core of our algorithm is based on an estimation of the magnetic field gradients by a least-square…

Instrumentation and Methods for Astrophysics · Physics 2023-09-29 Oliver Zier , Alexander C. Mayer , Volker Springel

We review the numerical techniques for ideal and non-ideal magneto-hydrodynamics (MHD) used in the context of star formation simulations. We outline the specific challenges offered by modeling star forming environments, which are dominated…

Instrumentation and Methods for Astrophysics · Physics 2019-07-22 Romain Teyssier , Benoit Commercon

Magnetised plasma turbulence pervades the universe and is likely to play an important role in a variety of astrophysical settings. Magnetohydrodynamics (MHD) provides the simplest theoretical framework in which phenomenological models for…

Plasma Physics · Physics 2012-07-23 Joanne Mason , Jean C. Perez , Stanislav Boldyrev , Fausto Cattaneo

Observations, mainly of outbursts in dwarf novae, imply that the anomalous viscosity in highly ionized accretion discs is magnetic in origin, and requires that the plasma $\beta \sim 1$. Until now most simulations of the magnetic dynamo in…

Plasma Physics · Physics 2023-12-08 C. J. Nixon , C. C. T. Pringle , J. E. Pringle

We consider the long time behavior of solutions to the magnetohydrodynamics equations in two and three spatial dimensions. It is shown that in the absence of magnetic diffusion, if strong bounded solutions were to exist their energy cannot…

Analysis of PDEs · Mathematics 2007-05-23 Ruben Agapito , Maria Schonbek

We present 2D MHD numerical simulations of tearing-unstable current sheets coupled to a population of non-thermal test-particles, in order to address the problem of numerical convergence with respect to grid resolution, numerical method and…

Plasma Physics · Physics 2021-10-15 Eleonora Puzzoni , Andrea Mignone , Gianluigi Bodo

The magnetic field through the magnetic reconnection process affects the dynamics and structure of astrophysical systems. Numerical simulations are the tools to study the evolution of these systems. However, the resolution, dimensions,…

Plasma Physics · Physics 2023-12-13 Fatemeh Kayanikhoo , Miljenko Cemeljic , Maciek Wielgus , Wlodek Kluzniak

Turbulent diffuse molecular clouds can exhibit complicated morphologies caused by the interactions among radiation, chemistry, fluids, and fields. We performed full 3D simulations for turbulent diffuse molecular interstellar media,…

Astrophysics of Galaxies · Physics 2024-07-17 Nannan Yue , Lile Wang , Thomas Bisbas , Donghui Quan , Di Li
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