Related papers: Structured outflow from a dynamo active accretion …
We investigate the significance of large scale azimuthal, magnetic and velocity modes for the MRI turbulence in accretion disks. We perform 3D global ideal MHD simulations of global stratified proto-planetary disk models. Our domains span…
We investigate accretion onto a central star, with the size, rotation rate, and magnetic dipole of a young stellar object, to study the flow pattern (velocity and density) of the fluid within and outside of the disc. We perform resistive…
A model for axisymmetric magnetized accretion flow is proposed. The dominant mechanism of energy dissipation is assumed to be the magnetic diffusivity due to turbulence in the accretion flow. In analogy to the advection-dominated accretion…
We present a three-dimensional model of rotating convection combined with a simplified corona in spherical coordinates. The motions in the convection zone generate a large-scale magnetic field that gets sporadically ejected into the outer…
We examine, parametrically, the interaction between the magnetosphere of a rotating, young stellar object (YSO) and a circumstellar accretion disk using 2.5-D (cylindrically symmetric) numerical magnetoydrodynamic simulations. The…
Small-scale winds driven from accretion discs surrounding active galactic nuclei (AGN) are expected to launch kpc-scale outflows into their host galaxies. However, the ways in which the structure of the interstellar medium (ISM) affects the…
Mass loss appears to be a common phenomenon among disk-accreting astrophysical systems. An outflow emanating from an accretion disk can act as a sink for mass, angular momentum and energy and can therefore alter the dissipation rates and…
Jets and outflows are observed around a wide variety of accreting objects and seem to be a near-ubiquitous feature of accretion disks. Large-scale magnetic fields are thought to be necessary for jet formation in many systems, but a…
We investigate the properties of a hot accretion flow bathed in a poloidal magnetic field. We consider an axisymmetric viscous resistive flow in the steady state configuration. We assume the dominant mechanism of energy dissipation is due…
We follow numerically the time evolution of axisymmetric outflows driven magneto-centrifugally from the inner portion of accretion disks, from their launching surface to large, observable distances. Special attention is paid to the…
Core convection and dynamo activity deep within rotating A-type stars of 2 solar masses are studied with 3--D nonlinear simulations. Our modeling considers the inner 30% by radius of such stars, thus capturing within a spherical domain the…
In their early stages, protoplanetary discs are sufficiently massive to undergo gravitational instability (GI). This instability is thought to be involved in mass accretion, planet formation via gas fragmentation, the generation of spiral…
Context: Convectively-driven flows play a crucial role in the dynamo processes that are responsible for producing magnetic activity in stars and planets. It is still not fully understood why many astrophysical magnetic fields have a…
We present a model of a viscously evolving accretion disc around a magnetized neutron star. The model features the varying outer radius of the hot ionized part of the disc due to cooling and the varying inner radius of the disc due to…
The time-scales of the variabilities in changing look (CL) active galactic nuclei (AGNs) are usually at the order of years to tens of years (some of them are even shorter than one year), which are much shorter than the viscous timescale of…
The launching of magnetohydrodynamic outflows from accretion disks is considered. We formulate a model for the local vertical structure of a thin disk threaded by a poloidal magnetic field of dipolar symmetry. The model consists of an…
We present a realistic numerical model of sunspot and active region formation based on the emergence of flux bundles generated in a solar convective dynamo. To this end we use the magnetic and velocity fields in a horizontal layer near the…
The evolution of an initially stellar dipole type magnetosphere interacting with an accretion disk is investigated using numerical ideal MHD simulations. The simulations follow several 1000 Keplerian periods of the inner disk. The initial…
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…
We discuss asymptotic solutions of the kinematic $\alpha\omega$-dynamo in a thin disc (slab). Focusing upon the strong dynamo regime, in which the dynamo number $D$ satisfies $|D|\gg1$, we resolve uncertainties in the earlier treatments and…