13-18 December 2015
International Conference Centre Geneva
Europe/Zurich timezone

Resistive GRMHD simulations of accretion disks around Kerr black holes: connecting large and small scales

17 Dec 2015, 16:15
21m
Level 0, Room 23 (International Conference Centre Geneva)

Level 0, Room 23

International Conference Centre Geneva

17 Rue de Varembé, 1211 Geneva

Speaker

Matteo Bugli (Max Planck Institute for Astrophysics)

Description

Accretion on compact objects is commonly considered the most plausible mechanism to power up a list of astrophysical systems (such as AGNs, GRBs, X-Ray Binaries, etc. . . ) and in particular magnetic fields are believed to play a major role in enabling the accretion process through the development of magnetic instabilities. We investigated the effects of a finite resistivity in a magnetized plasma orbiting around a rotating black hole in a fully covariant framework, providing a self-consistent closure for the Ohm law and performing 3D GRMHD simulations with a highly parallelized version of the ECHO code. We studied in particular the development of the Papaloizou-Pringle instability (PPI) and how it is affected by non-ideal effects, starting with different magnetic configurations and disk models. We also investigate the effects of a mean-field dynamo closure on axisymmetric disks, in order to address the question about the origin of the large-scale magnetic fields required in such systems: starting from a kinematic regime, we extend previous results to take into account a fully dynamical development of the magnetic field through a quenched $\alpha\Omega$-dynamo.

Primary author

Matteo Bugli (Max Planck Institute for Astrophysics)

Co-authors

Dr Ewald Mueller (Max Planck Institute for Astrophysics) Dr Luca Del Zanna (Universita' degli Studi di Firenze) Dr Niccolo' Bucciantini (INAF) Dr Pedro Montero (Max Planck Institute for Astrophysics)

Presentation Materials