Magnetorotational dynamo can generate large-scale vertical magnetic fields in 3D GRMHD simulations of accreting black holes

Understand

Jetted astrophysical phenomena with black hole (BH) engines, including binary mergers, jetted tidal disruption events, and X-ray binaries, require a large-scale vertical magnetic field for efficient jet formation.

• However, a dynamo mechanism that could generate these crucial large-scale magnetic fields has not been identified and characterized.
• We have employed 3D global general relativistic magnetohydrodynamical (MHD) simulations of accretion disks to quantify, for the first time, a dynamo mechanism that generates large-scale magnetic fields.
• This dynamo mechanism primarily arises from the nonlinear evolution of the magnetorotational instability (MRI).