Obliquity of Black Hole Magnetosphere and Its Impact on Accretion Dynamics

Ishika Palit^1*, Indu Kalpa Dihingia², Yosuke Mizuno², Hsiang-Yi Karen Yang¹

¹Institute of Astronomy, Dept. of Physics, National Tsing Hua University, Hsinchu City, Taiwan
²Tsung-Dao Lee Institute, Shanghai Jiao-Tong University, Shanghai, China

* Presenter:Ishika Palit, email:v01853@phys.nthu.edu.tw

We investigate the impact of magnetic field inclination on accretion dynamics around a spinning black hole using axisymmetric general relativistic magnetohydrodynamic simulations. We use a Fishbone–Moncrief initial torus around a Kerr black hole with spin parameter a = 0.9375, threaded by large-scale magnetic fields inclined at angles of 30o, 45o, and 60o relative to the spin axis. We examine how magnetic obliquity alters magnetic field geometry, accretion flow morphology, and angular momentum transport across a range of initial plasma beta values ( b = 0.007, 0.005, 0.001). We find that increasing magnetic inclination leads to significant tilting and deformation of the inner disk region, asymmetric outflows, and time-dependent variations in accretion rates. The magnetic field configuration evolves dynamically, with enhanced reconnection activity and complex current sheet structures forming near the event horizon. These effects are more pronounced at lower beta values, where magnetic pressure dominates. Our results demonstrate that magnetic obliquity plays a crucial role in shaping the structure and variability of relativistic accretion flows, with potential observational consequences for jet orientation and variability timescales in observed astrophysical sources. This study highlights the need to consider misaligned magnetic configurations in modeling some astrophysical black hole environments.

Keywords: Jets, GRMHD simualtions, magnetohydrodynamics, High energy astrophysics, Black hole physics