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Magnetic fields are expected to be efficiently amplified during the formation of the first massive black holes via the small-scale dynamo and in the presence of strong accretion shocks occurring during gravitational collapse. Here, we…

High Energy Astrophysical Phenomena · Physics 2023-07-26 Muhammad A. Latif , Dominik R. G. Schleicher

We investigate the conditions required for planet formation via gravitational instability (GI) and protoplanetary disk (PPD) fragmentation around M-dwarfs. Using a suite of 64 SPH simulations with $10^6$ particles, the parameter space of…

Earth and Planetary Astrophysics · Physics 2016-08-04 Isaac Backus , Thomas Quinn

We use adaptive-mesh magnetohydrodynamic simulations to study the effect of magnetic fields on ram pressure stripping of galaxies in the intracluster medium (ICM). Although the magnetic pressure in typical clusters is not strong enough to…

High Energy Astrophysical Phenomena · Physics 2017-05-31 Rukmani Vijayaraghavan , Paul M. Ricker

Magnetorotational turbulence provides a viable mechanism for angular momentum transport in accretion disks. We present global, three dimensional (3D), MHD accretion disk simulations that investigate the dependence of the turbulent stresses…

High Energy Astrophysical Phenomena · Physics 2015-06-16 E. R. Parkin , G. V. Bicknell

Magnetic fields are often invoked as playing a primary role in star formation and in the formation of high-mass stars. We investigate the effect of magnetic fields on the formation of high-mass cores using the 3-dimensional smoothed…

Astrophysics of Galaxies · Physics 2025-04-04 Katerina Sophia Klos , Ian A. Bonnell , Rowan J. Smith

Predicting the final state of turbulent plasma relaxation is an important challenge, both in astrophysical plasmas such as the Sun's corona and in controlled thermonuclear fusion. Recent numerical simulations of plasma relaxation with…

Plasma Physics · Physics 2015-05-11 A. R. Yeates , A. J. B. Russell , G. Hornig

Previous axisymmetric investigations in two dimensions (2D) have shown that rings and gaps develop naturally in non-ideal magnetohydrodynamic (MHD) disk-wind systems, especially in the presence of ambipolar diffusion (AD). Here we extend…

Solar and Stellar Astrophysics · Physics 2019-01-09 Scott S. Suriano , Zhi-Yun Li , Ruben Krasnopolsky , Takeru K. Suzuki , Hsien Shang

We have studied the magnetic relaxation behavior of a two-dimensional Ising ferromagnet by Monte Carlo simulation. Our primary goal is to investigate the effects of the system's geometry (area preserving) , boundary conditions, and…

Statistical Mechanics · Physics 2023-11-21 Ishita Tikader , Olivia Mallick , Muktish Acharyya

It is established that the formation of rotationally supported disks during the main accretion phase of star formation is suppressed by a moderately strong magnetic field in the ideal MHD limit. Non-ideal MHD effects are expected to weaken…

Astrophysics · Physics 2011-02-11 Richard R. Mellon , Zhi-Yun Li

The inner regions of protoplanetary discs, which encompass the putative habitable zone, are dynamically complex, featuring a relatively well-ionised, turbulent active zone located interior to a poorly ionised 'dead' zone. In this second…

Earth and Planetary Astrophysics · Physics 2026-04-29 Matthew J. O. Roberts , Henrik N. Latter , Geoffroy Lesur

We carried out global three-dimensional resistive magnetohydrodynamic simulations of galactic gaseous disks to investigate how the galactic magnetic fields are amplified and maintained. We adopt a steady axisymmetric gravitational potential…

Astrophysics · Physics 2009-11-11 Hiromitsu Nishikori , Mami Machida , Ryoji Matsumoto

The transport of angular momentum by magnetic fields is a crucial physical process in formation and evolution of stars and disks. Because the ionization degree in star forming clouds is extremely low, non-ideal magnetohydrodynamic (MHD)…

Solar and Stellar Astrophysics · Physics 2015-06-23 Kengo Tomida , Satoshi Okuzumi , Masahiro N. Machida

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

We present an analytic, quasi-local model for accretion discs threaded by net, vertical magnetic flux. In a simple slab geometry and ignoring stochastic mean-field dynamo effects, we calculate the large-scale field resulting from the…

High Energy Astrophysical Phenomena · Physics 2024-10-18 Mitchell C. Begelman

Cold steady-state disk wind theory from near Keplerian accretion disks requires a large scale magnetic field at near equipartition strength. However the minimum magnetization has never been tested. We investigate the time evolution of an…

Solar and Stellar Astrophysics · Physics 2015-03-13 Gareth C. Murphy , Jonathan Ferreira , Claudio Zanni

Magnetic fields likely play a key role in the dynamics and evolution of protoplanetary discs. They have the potential to efficiently transport angular momentum by MHD turbulence or via the magnetocentrifugal acceleration of outflows from…

Astrophysics · Physics 2009-06-23 Mark Wardle

We present an experimental and numerical study of three-magnon splitting in a micrometer-sized magnetic disk with the vortex state strongly deformed by static in-plane magnetic fields. Excited with a large enough power at frequency…

Mesoscale and Nanoscale Physics · Physics 2023-03-08 Lukas Körber , Christopher Heins , Ivan Soldatov , Rudolf Schäfer , Attila Kákay , Helmut Schultheiss , Katrin Schultheiss

The excitation of trapped inertial waves (r-modes) by warps and eccentricities in the inner regions of a black hole accretion disc may explain the high-frequency quasi-periodic oscillations (HFQPOs) observed in the emission of Galactic…

High Energy Astrophysical Phenomena · Physics 2023-04-12 Janosz W. Dewberry , Henrik N. Latter , Gordon I. Ogilvie

In recent years, many wide orbit circumbinary giant planets have been discovered; some of these may have formed by gravitational fragmentation of circumbinary discs. The aim of this work is to investigate the lower mass limit for…

Solar and Stellar Astrophysics · Physics 2026-01-08 Matthew Teasdale , Dimitris Stamatellos

We investigate hydromagnetic turbulence of primordial magnetic fields using magnetohydrodynamics (MHD) in an expanding universe. We present the basic, covariant MHD equations, find solutions for MHD waves in the early universe, and…

Astrophysics · Physics 2014-10-13 Axel Brandenburg , Kari Enqvist , Poul Olesen