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The amplification of primordial magnetic fields via a small-scale turbulent dynamo during structure formation might be able to explain the observed magnetic fields in galaxy clusters. The magnetisation of more tenuous large-scale structures…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 F. Vazza , M. Brüggen , C. Gheller , P. Wang

The small-scale turbulent dynamo is a key mechanism for amplifying galactic magnetic fields, yet the resulting field morphology remains poorly understood. Using 3D driven turbulence simulations across a range of compressibilities,…

Astrophysics of Galaxies · Physics 2026-03-25 Sasi M. Behara , Amit Seta

Context: Dust grains undergo significant growth in star-forming environments, especially in dense regions prone to gravitational collapse. Although dust is generally assumed to represent $1 \%$ of the gas mass, dust density variations are…

Astrophysics of Galaxies · Physics 2026-01-14 V. Vallucci-Goy , P. Hennebelle , U. Lebreuilly , G. Verrier

We numerically investigate the driving of MHD turbulence by gravitational contraction using simulations of an initially spherical, magnetically supercritical cloud core with initially transonic and trans-Alfv\'enic turbulence. We perform a…

Astrophysics of Galaxies · Physics 2024-03-04 Enrique Vázquez-Semadeni , Yue Hu , Siyao Xu , Rubén Guerrero-Gamboa , Alex Lazarian

Recent Chandra and XMM-Newton observations of galaxy cluster cooling flows have revealed X-ray emission voids of up to 30 kpc in size that have been identified with buoyant, magnetized bubbles. Motivated by these observations, we have…

We investigate numerically the combined effects of supersonic turbulence, strong magnetic fields and ambipolar diffusion on cloud evolution leading to star formation. We find that, in clouds that are initially magnetically subcritical,…

Astrophysics · Physics 2009-11-10 Zhi-Yun Li , Fumitaka Nakamura

The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as…

Spectropolarimetric observations show that many low-mass stars possess large-scale poloidal magnetic fields with considerable dipole component, which in some cases exhibit temporal dynamics - cycles or reversals. Although it is widely…

Solar and Stellar Astrophysics · Physics 2025-07-02 Anna Guseva , Ludovic Petitdemange , Charly Pinçon

We report results of a three dimensional, high resolution (up to 512^3) numerical investigation of supersonic compressible magnetohydrodynamic turbulence. We consider both forced and decaying turbulence. The model parameters are appropriate…

Astrophysics · Physics 2009-10-30 James M. Stone , Eve C. Ostriker , Charles F. Gammie

Our Sun exhibits strong convective dynamo action which results in magnetic flux bundles emerging through the stellar surface as magnetic spots. Global-scale dynamo action is believed to generate large-scale magnetic structures in the deep…

Solar and Stellar Astrophysics · Physics 2014-03-05 Nicholas J. Nelson , Mark S. Miesch

We summarize recent numerical results on the control of the star formation efficiency (SFE), addressing the effects of turbulence and the magnetic field strength. In closed-box numerical simulations, the effect of the turbulent Mach number…

Astrophysics · Physics 2009-11-11 Enrique Vazquez-Semadeni

The importance of the interstellar magnetic field is studied in relation to the evolutions of superbubbles with a three-dimensional (3D) numerical magnetohydrodynamical (MHD) simulation. A superbubble is a large supernova remnant driven by…

Astrophysics · Physics 2009-10-30 Kohji Tomisaka

Neutron stars, and magnetars in particular, are known to host the strongest magnetic fields in the Universe. The origin of these strong fields is a matter of controversy. In this preliminary work, via numerical simulations, we study, for…

High Energy Astrophysical Phenomena · Physics 2020-06-30 K. Franceschetti , L. Del Zanna

Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…

Astrophysics · Physics 2007-05-23 Ralf Klessen

Hydrodynamic supersonic turbulence can only prevent local gravitational collapse if the turbulence is driven on scales smaller than the local Jeans lengths in the densest regions, a very severe requirement (Paper I). Magnetic fields have…

Astrophysics · Physics 2010-10-28 F. Heitsch , M. -M. Mac Low , R. S. Klessen

We report an extensive set of two-dimensional MHD simulations exploring the role and evolution of magnetic fields in the dynamics of supersonic plasma clumps. We examine the influence of both ambient field strength and orientation on the…

Astrophysics · Physics 2009-10-28 T. W. Jones , Dongsu Ryu , I. L. Tregillis

We investigate the influence of magnetic field amplification on the core-collapse supernovae in highly magnetized progenitors through three-dimensional simulations. By considering rotating models, we observe a strong correlation between the…

High Energy Astrophysical Phenomena · Physics 2023-12-22 Jin Matsumoto , Tomoya Takiwaki , Kei Kotake

We present results from two-dimensional numerical simulations of a supersonic turbulent flow in the plane of the galactic disk, incorporating shear, thresholded and discrete star formation (SF), self-gravity, rotation and magnetic fields. A…

Astrophysics · Physics 2009-10-28 T. Passot , E. Vazquez-Semadeni , A. Pouquet

The formation of stars occurs in the dense molecular cloud phase of the interstellar medium. Observations and numerical simulations of molecular clouds have shown that supersonic magnetised turbulence plays a key role for the formation of…

Astrophysics of Galaxies · Physics 2016-08-17 Andrew Lehmann , Christoph Federrath , Mark Wardle

Many explosive astrophysical events, like magnetars' bursts and flares, are magnetically driven. We consider dynamics of such magnetic explosions - relativistic expansion of highly magnetized and highly magnetically over-pressurized clouds.…

High Energy Astrophysical Phenomena · Physics 2022-08-17 Maxim V. Barkov , Praveen Sharma , Konstantinos N. Gourgouliatos , Maxim Lyutikov