Related papers: Enhanced Angular Momentum Transport in Accretion D…
After the initial stage of fast expanding of the hot Universe comes epoch of temperature fall and subsequent formation of dense clouds of hydrogen. Due to process of accretion some of this clouds became compact objects. Initially accretion…
We briefly review recent developments in black hole accretion disk theory, placing new emphasis on the vital role played by magnetohydrodynamic (MHD) stresses in transporting angular momentum. The apparent universality of accretion-related…
We perform controlled N-Body/SPH simulations of disk galaxy formation by cooling a rotating gaseous mass distribution inside equilibrium cuspy spherical and triaxial dark matter halos. We systematically study the angular momentum transport…
Angular momentum transport and particle acceleration during the magnetorotational instability (MRI) in a collisionless accretion disk are investigated using three-dimensional particle-in-cell (PIC) simulation. We show that the kinetic MRI…
Astrophysical accretion is arguably the most prevalent physical process in the Universe; it occurs during the birth and death of individual stars and plays a pivotal role in the evolution of entire galaxies. Accretion onto a black hole, in…
The existing disk instability model for dwarf nova eruptions is reviewed, in the light of recent progress in the understanding of angular momentum transport in accretion disks. It is proposed that the standard lower branch in the…
In accretion disks with large-scale ordered magnetic fields, the magnetorotational instability (MRI) is marginally suppressed, so other processes may drive angular momentum transport leading to accretion. Accretion could then be driven by…
This work derives the linearized equations of motion, the Lagrangian density, the Hamiltonian density, and the canonical angular momentum density for general perturbations [$\propto \exp(im\phi)$ with $m=0,\pm 1,..$] of a geometrically thin…
Throughout the Hubble time, gas makes its way from the intergalactic medium into galaxies fuelling their star formation and promoting their growth. One of the key properties of the accreting gas is its angular momentum, which has profound…
The magnetorotational instability (MRI) is believed to be responsible for most of the angular momentum transport in accretion discs. However, molecular dissipation processes may drastically change the efficiency of MRI turbulence in…
Angular momentum in protostellar discs can be transported either radially, through turbulence induced by the magnetorotational instability (MRI), or vertically, through the torque exerted by a large-scale magnetic field. We present a model…
I briefly review the theoretical models of radiatively efficient, geometrically thin and optically thick accretion disk spectra that currently exist for AGN. I then discuss three recent observational developments that have real potential to…
We perform global unstratified 3D magnetohydrodynamic simulations of an astrophysical boundary layer (BL) -- an interface region between an accretion disk and a weakly magnetized accreting object such as a white dwarf -- with the goal of…
The origin of hydrodynamic turbulence, and in particular of an anomalously enhanced angular momentum transport, in accretion disks is still an unsolved problem. This is especially important for cold disk systems which are practically…
We perform global three-dimensional simulations of accretion disks integrating the compressible, non-viscous, but diffusive MHD equations. The disk is supposed to be isothermal. We make use of the ZEUS-3D code integrating the MHD equations…
The conventional accretion disk lore is that magnetized turbulence is the principal angular momentum transport process that drives accretion. However, when dynamically important large-scale magnetic fields thread an accretion disk, they can…
We examine the angular momentum transport properties of disks composed of macroscopic particles whose velocity dispersions are externally enhanced (``stirred''). Our simple Boltzmann equation model serves as an analogy for unmagnetized…
In this paper we present the global baroclinic instability as a source for vigorous turbulence leading to angular momentum transport in Keplerian accretion disks. We show by analytical considerations and three-dimensional radiation hydro…
Numerical MHD codes have become extraordinarily powerful tools with which to study accretion turbulence. They have been used primarily to extract values for the classical $\alpha$ parameter, and to follow complex evolutionary development.…
We briefly review recent developments in black hole accretion disk theory, emphasizing the vital role played by magnetohydrodynamic (MHD) stresses in transporting angular momentum. The apparent universality of accretion-related outflow…