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Related papers: Ambipolar diffusion: Self-similar solutions and MH…

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Thermal instability is one of the most important processes in the formation of clumpy substructure in magnetic molecular clouds. On the other hand, ambipolar diffusion, or ion-neutral friction, has long been thought to be an important…

Astrophysics · Physics 2009-11-10 Mohsen Nejad-Asghar , Jamshid Ghanbari

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

In this paper we introduce a new method for exact decomposition of propagating, nonlinear magnetohydrodynamic (MHD) disturbances into their component eigenenergies associated with the familiar slow, Alfv\'en, and fast wave eigenmodes, and…

Solar and Stellar Astrophysics · Physics 2024-02-09 Abbas Raboonik , Lucas Tarr , David Pontin

In theory, diffusion curves promise complex color gradations for infinite-resolution vector graphics. In practice, existing realizations suffer from poor scaling, discretization artifacts, or insufficient support for rich boundary…

Numerical Analysis · Mathematics 2023-11-27 Seungbae Bang , Kirill Serkh , Oded Stein , Alec Jacobson

In this paper we investigate a sub-diffusion equation for simulating the anomalous diffusion phenomenon in real physical environment. Based on an equivalent transformation of the original sub-diffusion equation followed by the use of a…

Numerical Analysis · Mathematics 2018-03-29 Zongze Yang , Jungang Wang , Yan Li , Yufeng Nie

Collapse of the rotating magnetized molecular cloud core is studied with the axisymmetric magnetohydrodynamical (MHD) simulations. Due to the change of the equation of state of the interstellar gas, the molecular cloud cores experience…

Astrophysics · Physics 2009-11-06 Kohji Tomisaka

(Abridged) We develop an analytical spectral method to solve the equations of equilibrium for a self-gravitating, magnetized fluid body, under the only hypotheses that (a) the equation of state is isothermal, (b) the configuration is…

Astrophysics · Physics 2009-11-10 Daniele Galli

This paper examines a new class of exact and self-consistent MHD solutions which describe steady and axisymmetric hydromagnetic outflows from the atmosphere of a magnetized and rotating central object with possibly an orbiting accretion…

Astrophysics · Physics 2009-10-31 N. Vlahakis , K. Tsinganos

In this paper, we propose high order numerical methods to solve a 2D advection diffusion equation, in the highly oscillatory regime. We use an integrator strategy that allows the construction of arbitrary high-order schemes {leading} to an…

Numerical Analysis · Mathematics 2024-11-11 Clarissa Astuto

Context: Numerical simulations of stellar convection and photospheres have been developed to the point where detailed shapes of observed spectral lines can be explained. Stellar atmospheres are very complex, and very different physical…

Solar and Stellar Astrophysics · Physics 2015-05-28 Boris V. Gudiksen , Mats Carlsson , Viggo H. Hansteen , Wolfgang Hayek , Jorrit Leenaarts , Juan Martínez-Sykora

Magnetic reconnection is a fundamental mechanism in astrophysics. A common challenge in mimicking this process numerically in particular for the Sun is that the solar electrical resistivity is small compared to the diffusive effects caused…

Solar and Stellar Astrophysics · Physics 2023-07-05 Øystein Håvard Færder , Daniel Nóbrega-Siverio , Mats Carlsson

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

We present a new magnetohydrodynamic (MHD) simulation code with the aim of providing accurate numerical solutions to astrophysical phenomena where discontinuities, shock waves, and turbulence are inherently important. The code implements…

We present a few explicit counterexamples to the widely spread belief about an exclusive role of the bimodal nuclear fragment size distributions as the first order phase transition signal. In thermodynamic limit the bimodality may appear at…

Nuclear Theory · Physics 2013-11-28 V. V. Sagun , A. I. Ivanytskyi , K. A. Bugaev , D. R. Oliinychenko

In this study, we presented the high-order fundamental solutions and general solutions of convection-diffusion equation. To demonstrate their efficacy, we applied the high-order general solutions to the boundary particle method (BPM) for…

Computational Engineering, Finance, and Science · Computer Science 2007-05-23 W. Chen

Protostars are born in magnetized environments. As a consequence, the formation of protostellar disks can be suppressed by the magnetic field efficiently removing angular momentum of the infalling material. Non-ideal MHD effects are…

Solar and Stellar Astrophysics · Physics 2024-04-26 Travis J. Thieme , Shih-Ping Lai , Yueh-Ning Lee , Sheng-Jun Lin , Hsi-Wei Yen

This paper describes the first steps of development of a new multidimensional time implicit code devoted to the study of hydrodynamical processes in stellar interiors. The code solves the hydrodynamical equations in spherical geometry and…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 M. Viallet , I. Baraffe , R. Walder

The evolution of electromagnetic and thermodynamic fields in a non-ideal fluid are studied in the framework of ultrarelativistic transverse magnetohydrodynamics (MHD), which is essentially characterized by electric and magnetic fields being…

Nuclear Theory · Physics 2017-12-20 M. Shokri , N. Sadooghi

Treating water as a linearly responding dielectric continuum on molecular length scales allows very simple estimates of solvation structure and thermodynamics for charged and polar solutes. While this approach can successfully account for…

Statistical Mechanics · Physics 2021-07-07 Stephen J. Cox , Kranthi K. Mandadapu , Phillip L. Geissler

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