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Related papers: Incorporating Ambipolar and Ohmic Diffusion in the…

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Turbulent motion driven by the magnetorotational instability (MRI) is believed to provide an anomalous viscosity strong enough to account for observed accretion rates in protostellar accretion disks. In the first of two papers, we perform…

Solar and Stellar Astrophysics · Physics 2015-06-19 Wayne O'Keeffe , Turlough P. Downes

We present a novel method of magnetohydrodynamics (MHD) within the smoothed particle hydrodynamics scheme using the Geometric Density average force expression (GDSPH). GDSPH has recently been shown to reduce the leading order errors and…

Instrumentation and Methods for Astrophysics · Physics 2020-07-31 Robert Wissing , Sijing Shen

The partial ionization of the solar plasma causes several nonideal effects such as the ambipolar diffusion, the Hall effect, and the Biermann battery effect. Here we report on the first three-dimensional realistic simulations of solar local…

Solar and Stellar Astrophysics · Physics 2020-11-04 P. A. Gonzalez-Morales , E. Khomenko , N. Vitas , M. Collados

We present an anisotropic goal-oriented error estimator based on the Dual Weighted Residual (DWR) method for time-dependent convection-diffusion-reaction (CDR) equations. Using anisotropic interpolation operators the estimator is…

Numerical Analysis · Mathematics 2025-04-22 M. Bause , M. Bruchhäuser , B. Endtmayer , N. Margenberg , I. Toulopoulos , T. Wick

A high order one-step ADER-WENO finite volume scheme with Adaptive Mesh Refinement (AMR) in multiple space dimensions is presented. A high order one-step time discretization is achieved using a local space-time discontinuous Galerkin…

Instrumentation and Methods for Astrophysics · Physics 2014-01-27 Olindo Zanotti , Michael Dumbser , Arturo Hidalgo , Dinshaw Balsara

We examine the range of rest-mass densities, temperatures and magnetic fields involved in simulations of binary neutron star mergers (BNSM) and identify the conditions under which the ideal magneto-hydrodynamics (MHD) breaks down using…

High Energy Astrophysical Phenomena · Physics 2019-07-12 Arus S. Harutyunyan

We investigate the question of whether ambipolar diffusion (ion-neutral drift) determines the smallest length and mass scale on which structure forms in a turbulent molecular cloud. We simulate magnetized turbulence in a mostly neutral,…

Astrophysics · Physics 2009-11-13 Jeffrey S. Oishi , Mordecai-Mark Mac Low

Solving the Euler equations of ideal hydrodynamics as accurately and efficiently as possible is a key requirement in many astrophysical simulations. It is therefore important to continuously advance the numerical methods implemented in…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-02 Kevin Schaal , Andreas Bauer , Praveen Chandrashekar , Rüdiger Pakmor , Christian Klingenberg , Volker Springel

Magnetohydrodynamics (MHD) is invoked to address turbulent fluctuations in a variety of astrophysical systems. MHD turbulence in nature is often anisotropic and imbalanced, in that Alfvenic fluctuations moving in opposite directions along…

Astrophysics of Galaxies · Physics 2010-02-18 Jean C Perez , Stanislav Boldyrev

Variational inequalities play a pivotal role in a wide array of scientific and engineering applications. This project presents two techniques for adaptive mesh refinement (AMR) in the context of variational inequalities, with a specific…

Numerical Analysis · Mathematics 2025-02-21 Giuliano Stefano Fochesatto

We propose to extend the well-known MUSCL-Hancock scheme for Euler equations to the induction equation modeling the magnetic field evolution in kinematic dynamo problems. The scheme is based on an integral form of the underlying…

Astrophysics · Physics 2009-11-11 R. Teyssier , S. Fromang , E. Dormy

We have derived the full set of MHD equations for incompressible shear flow of a magnetized fluid and considered their solution in the wave-vector space. The linearized equations give the famous amplification of slow magnetosonic waves and…

Plasma Physics · Physics 2015-05-27 Z. D. Dimitrov , Y. G. Maneva , T. S. Hristov , T. M. Mishonov

We present Variable Eddington Tensor-closed Transport on Adaptive Meshes (\texttt{VETTAM}), a new algorithm to solve the equations of radiation hydrodynamics (RHD) with support for adaptive mesh refinement (AMR) in a frequency-integrated,…

Instrumentation and Methods for Astrophysics · Physics 2022-03-02 Shyam H. Menon , Christoph Federrath , Mark R. Krumholz , Rolf Kuiper , Benjamin D. Wibking , Manuel Jung

A pair of nonlinear diffusion equations in Fourier space} is used to study the dynamics of strong Alfv\'en-wave turbulence, from MHD to electron scales. Special attention is paid to the regime of imbalance between the energies of…

Plasma Physics · Physics 2019-12-12 George Miloshevich , Thierry Passot , Pierre-Louis Sulem

We develop a detailed chemical network relevant to the conditions characteristic of prestellar core collapse. We solve the system of time-dependent differential equations to calculate the equilibrium abundances of molecules and dust grains,…

Astrophysics of Galaxies · Physics 2016-07-06 Pierre Marchand , Jacques Masson , Gilles Chabrier , Patrick Hennebelle , Benoit Commerçon , Neil Vaytet

In the presence of a strong uniform magnetic field, we study the influence of space noncommutativity on the electromagnetic waves propagating through a quasi-static homogeneous plasma. In this treatment, we have adopted a physical model…

High Energy Physics - Theory · Physics 2008-11-26 S. Bourouaine , A. Benslama

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

This paper presents applications of weighted meshless scheme for conservation laws to the Euler equations and the equations of ideal magnetohydrodynamics. The divergence constraint of the latter is maintained to the truncation error by a…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Evghenii Gaburov , Keigo Nitadori

In recent years, the multitask diffusion least mean square (MD-LMS) algorithm has been extensively applied in the distributed parameter estimation and target tracking of multitask network. However, its performance is mainly limited by two…

Signal Processing · Electrical Eng. & Systems 2022-10-21 Wenjing Xu , Haiquan Zhao , Shaohui Lv

Cosmic rays (CRs) are thought to play a dynamically important role in several key aspects of galaxy evolution, including the structure of the interstellar medium, the formation of galactic winds, and the non-thermal pressure support of…

Astrophysics of Galaxies · Physics 2019-11-19 Yohan Dubois , Benoît Commerçon , Alexandre Marcowith , Loann Brahimi