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Magnetic fields play an important role in star formation by regulating the removal of angular momentum from collapsing molecular cloud cores. Hall diffusion is known to be important to the magnetic field behaviour at many of the…

Solar and Stellar Astrophysics · Physics 2011-10-12 Catherine Braiding

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

It is generally believed that turbulence has a significant impact on the dynamics and evolution of molecular clouds and the star formation which occurs within them. Non-ideal magnetohydrodynamic effects are known to influence the nature of…

Astrophysics of Galaxies · Physics 2015-03-17 Turlough P. Downes , Stephen O'Sullivan

We developed a one-dimensional magnetohydrodynamic (MHD) simulation code to investigate the long-term evolution of protoplanetary disks with low computational cost. In this simulation code, the physical processes necessary for protostellar…

Earth and Planetary Astrophysics · Physics 2025-08-11 Yudai Kobayashi , Daisuke Takaishi , Yusuke Tsukamoto , Shantanu Basu

Recent high resolution observations unveil ring structures in circumstellar disks. The origin of these rings has been widely investigated under various theoretical scenarios. In this work we perform global 3D non-ideal MHD simulations…

Earth and Planetary Astrophysics · Physics 2019-10-31 Xiao Hu , Zhaohuan Zhu , Satoshi Okuzumi , Xue-Ning Bai , Lile Wang , Kengo Tomida , James M. Stone

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 investigate the formation and evolution of a first core, protostar, and circumstellar disc with a three-dimensional non-ideal (including both Ohmic and ambipolar diffusion) radiation magnetohydrodynamics simulation. We found that the…

Solar and Stellar Astrophysics · Physics 2015-07-15 Yusuke Tsukamoto , Kazunari Iwasaki , Satoshi Okuzumi , Masahiro N. Machida , Shu-ichiro Inutsuka

The formation of protostellar disks out of molecular cloud cores is still not fully understood. Under ideal MHD conditions, the removal of angular momentum from the disk progenitor by the typically embedded magnetic field may prevent the…

Astrophysics of Galaxies · Physics 2015-05-30 R. Santos-Lima , E. M. de Gouveia Dal Pino , A. Lazarian

The effect of magnetic field diffusion on the stability of accretion disks is a problem that has attracted considerable interest of late. In particular, the Hall effect has the potential to bring about remarkable changes in the dynamical…

Earth and Planetary Astrophysics · Physics 2017-03-29 Gopakumar Mohandas , Martin E. Pessah

We investigate the formation and early evolution of a protostellar disc from a magnetized pre-stellar core using non-ideal magnetohydrodynamic (MHD) simulations including ambipolar diffusion and Ohmic dissipation. The dynamical contraction…

Solar and Stellar Astrophysics · Physics 2021-02-17 Wenrui Xu , Matthew W. Kunz

We present a linear analysis of the vertical structure and growth of the magnetorotational instability in stratified, weakly ionised accretion discs, such as protostellar and quiescent dwarf novae systems. The method includes the effects of…

Astrophysics · Physics 2009-11-10 Raquel Salmeron , Mark Wardle

Many mechanisms have been proposed to alleviate the magnetic catastrophe, which prevents the Keplerian disk from forming inside a collapsing magnetized core. Such propositions include inclined field and non-ideal magnetohydrodynamics…

Earth and Planetary Astrophysics · Physics 2024-01-08 Yueh-Ning Lee , Barshan Ray , Pierre Marchand , Patrick Hennebelle

We study dust transport in turbulent protoplanetary disks using three-dimensional global unstratified magnetohydrodynamic (MHD) simulations including Lagrangian dust particles. The turbulence is driven by the magnetorotational instability…

Earth and Planetary Astrophysics · Physics 2015-06-19 Zhaohuan Zhu , James M. Stone , Xue-Ning Bai

We present new analytical solutions for the evolution of protoplanetary discs (PPDs) where magnetohydrodynamic (MHD) wind-driven processes dominate. Our study uses a 1D model which incorporates equations detailing angular momentum…

Astrophysics of Galaxies · Physics 2024-01-19 Mohsen Shadmehri , Fazeleh Khajenabi

The grand question of star and planet formation is the distribution of magnetic flux in the protoplanetary disks. To answer it, a detailed self-consistent chemical evolution is needed to describe the magnetic dissipation in the collapsing…

Solar and Stellar Astrophysics · Physics 2017-07-26 Natalia Dzyurkevich , Benoit Commercon , Pierre Lesaffre , Dimitry Semenov

Given the important role turbulence plays in the settling and growth of dust grains in protoplanetary disks, it is crucial that we determine whether these disks are turbulent and to what extent. Protoplanetary disks are weakly ionized near…

Earth and Planetary Astrophysics · Physics 2024-04-12 David G. Rea , Jacob B. Simon , Daniel Carrera , Geoffroy Lesur , Wladimir Lyra , Debanjan Sengupta , Chao-Chin Yang , Andrew N. Youdin

Weakly ionized protoplanetary disks (PPDs) are subject to non-ideal-magnetohydrodynamic (MHD) effects including Ohmic resistivity, the Hall effect and ambipolar diffusion (AD), and the resulting magnetic diffusivities ($\eta_O, \eta_H$ and…

Earth and Planetary Astrophysics · Physics 2016-03-16 Rui Xu , Xue-Ning Bai

We investigate the linear growth and vertical structure of the magnetorotational instability (MRI) in weakly ionised, stratified accretion discs. The magnetic field is initially vertical and dust grains are assumed to have settled towards…

Astrophysics · Physics 2009-11-10 Raquel Salmeron , Mark Wardle

The transport of angular momentum is capital during the formation of low-mass stars; too little removal and rotation ensures stellar densities are never reached, too much and the absence of rotation means no protoplanetary disks can form.…

Solar and Stellar Astrophysics · Physics 2018-07-04 Neil Vaytet , Benoît Commerçon , Jacques Masson , Matthias González , Gilles Chabrier

A non-ideal MHD collapse calculation employing the axisymmetric thin-disk approximation is used to resolve cloud core collapse down to the scales of the second (stellar) core. Rotation and a magnetic braking torque are included in the…

Solar and Stellar Astrophysics · Physics 2013-08-19 Shantanu Basu , Wolf B. Dapp , Matthew W. Kunz