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.
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)
