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We investigate the evolution of the chiral magnetic instability in a protoneutron star and compute the resulting magnetic power and helicity spectra. The instability may act during the early cooling phase of the hot protoneutron star after…

High Energy Astrophysical Phenomena · Physics 2016-01-18 Günter Sigl , Natacha Leite

Protoplanetary disks are likely to be threaded by a weak net flux of vertical magnetic field that is a remnant of the much larger fluxes present in molecular cloud cores. If this flux is approximately conserved its dynamical importance will…

Earth and Planetary Astrophysics · Physics 2015-06-17 Philip J. Armitage , Jacob B. Simon , Rebecca G. Martin

Using local 3D MHD simulations, we investigate ways in which galactic turbulence associated with the magnetorotational instability (MRI) may influence the formation and properties of GMCs. Our disk models are vertically stratified and…

Astrophysics · Physics 2009-11-10 Woong-Tae Kim , Eve C. Ostriker , James M. Stone

Astrophysical disks are likely embedded in an ambient vertical magnetic field. This ambient field is known to drive magneto-rotational turbulence in the disk bulk but is also responsible for the launching of magnetized outflows at the…

High Energy Astrophysical Phenomena · Physics 2021-03-31 J. Jacquemin-Ide , G. Lesur , J. Ferreira

Mounting observational evidence indicates that cold circumstellar gas is present in debris disk systems. This work focuses on various dynamical processes that debris-disk gas may undergo. We review five mechanisms that can transport angular…

Earth and Planetary Astrophysics · Physics 2024-02-16 Can Cui , Sebastian Marino , Quentin Kral , Henrik Latter

We present an instability occurring in the inner part of disks threaded by a moderately strong vertical (poloidal) magnetic field. Its mechanism is such that a spiral density wave in the disk, driven by magnetic stresses (rather than…

Astrophysics · Physics 2007-05-23 M. Tagger , R. Pellat

Angular momentum transport in accretion disk has been the focus of intense research in theoretical astrophysics for many decades. In the past twenty years, MHD turbulence driven by the magnetorotational instability has emerged as an…

Solar and Stellar Astrophysics · Physics 2015-06-15 Sebastien Fromang

We present three-dimensional simulations of the dynamical bar-mode instability in magnetized and differentially rotating stars in full general relativity. Our focus is on the effects that magnetic fields have on the dynamics and the onset…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Luca Franci , Roberto De Pietri , Kyriaki Dionysopoulou , Luciano Rezzolla

The origin of turbulence in accretion discs is still not fully understood. While the magneto-rotational instability is considered to operate in sufficiently ionized discs, its role in the poorly ionized protoplanetary disc is questionable.…

Earth and Planetary Astrophysics · Physics 2014-12-03 Moritz H. R. Stoll , Wilhelm Kley

Intermittent large-scale high-shear flows are found to occur frequently and spontaneously in direct numerical simulations of statistically stationary turbulent Boussinesq magnetohydrodynamic (MHD) convection. The energetic steady-state of…

Solar and Stellar Astrophysics · Physics 2013-09-06 J. Pratt , A. Busse , W. -C. Mueller

Astrophysical fluids are turbulent, magnetized and frequently partially ionized. As an example of astrophysical turbulence, the interstellar turbulence extends over a remarkably large range of spatial scales and participates in key…

Astrophysics of Galaxies · Physics 2018-10-22 Siyao Xu , Alex Lazarian

Angular momentum transport in protostellar discs can take place either radially, through turbulence induced by the magnetorotational instability (MRI), or vertically, through the torque exerted by a large-scale magnetic field that threads…

Astrophysics · Physics 2008-11-26 Raquel Salmeron , Arieh Konigl , Mark Wardle

The remanent magnetisation of meteorite material in the solar system indicates that magnetic fields of several Gauss are present in the protoplanetary disk. It is shown that such relativelystrong magnetic fields can be generated in dusty…

Astrophysics · Physics 2007-05-23 G. T. Birk , H. Wiechen , A. Kopp , H. Lesch

We apply ionization balance and MHD calculations to investigate whether magnetic activity moderated by recombination on dust can account for the mass accretion rates and the mid-infrared spectra and variability of protostellar disks. The…

Earth and Planetary Astrophysics · Physics 2014-11-20 N. J. Turner , A. Carballido , T. Sano

The origin of hydrodynamic turbulence in rotating shear flow is a long standing puzzle. Resolving it is especially important in astrophysics when the flow angular momentum profile is Keplerian which forms an accretion disk having negligible…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Banibrata Mukhopadhyay , Kanak Saha

Planets are born in protostellar disks, which are now observed with enough resolution to address questions about internal gas flows. Candidates for driving the flows include magnetic forces, but ionization state estimates suggest much of…

We analyze the ionization state of the magnetohydrodynamically turbulent protoplanetary disks and propose a new mechanism of sustaining ionization. First, we show that in the quasi-steady state of turbulence driven by magnetorotational…

Astrophysics · Physics 2009-11-11 Shu-ichiro Inutsuka , Takayoshi Sano

We present simulations of the non-linear evolution of streaming instabilities in protoplanetary disks. The two components of the disk, gas treated with grid hydrodynamics and solids treated as superparticles, are mutually coupled by drag…

Astrophysics · Physics 2011-02-11 Anders Johansen , Andrew Youdin

The problem of three-dimensional combined magnetic and velocity shear driven instabilities of a compressible magnetized jet modeled with a plane neutral/current double vortex sheet in the framework of the resistive magnetohydrodynamics is…

Plasma Physics · Physics 2015-05-13 Lapo Bettarini , Simone Landi , Marco Velli , Pasquale Londrillo

The origin of large-scale and coherent magnetic fields in astrophysical discs is an important and long standing problem. Researchers commonly appeal to a turbulent dynamo, sustained by the magneto-rotational instability (MRI), to supply the…

High Energy Astrophysical Phenomena · Physics 2018-10-24 A. Riols , H. Latter