Black Hole Polar Jets:

[beecee]

https://academic.oup.com/mnrasl/article-abstract/474/1/L81/4566532?redirectedFrom=fulltext

 

Formation of precessing jets by tilted black hole discs in 3D general relativistic MHD simulations:

 

Abstract

Gas falling into a black hole (BH) from large distances is unaware of BH spin direction, and misalignment between the accretion disc and BH spin is expected to be common. However, the physics of tilted discs (e.g. angular momentum transport and jet formation) is poorly understood. Using our new GPU-accelerated code H-AMR, we performed 3D general relativistic magnetohydrodynamic simulations of tilted thick accretion discs around rapidly spinning BHs, at the highest resolution to date. We explored the limit where disc thermal pressure dominates magnetic pressure, and showed for the first time that, for different magnetic field strengths on the BH, these flows launch magnetized relativistic jets propagating along the rotation axis of the tilted disc (rather than of the BH). If strong large-scale magnetic flux reaches the BH, it bends the inner few gravitational radii of the disc and jets into partial alignment with the BH spin. On longer time-scales, the simulated disc–jet system as a whole undergoes Lense–Thirring precession and approaches alignment, demonstrating for the first time that jets can be used as probes of disc precession. When the disc turbulence is well resolved, our isolated discs spread out, causing both the alignment and precession to slow down.

Here is an article from "Universe Today" 

https://www.universetoday.com/138247/astronomers-figure-black-holes-can-blast-relativistic-jets-material-across-light-years-space/

ASTRONOMERS FIGURE OUT HOW BLACK HOLES CAN BLAST OUT RELATIVISTIC JETS OF MATERIAL ACROSS LIGHT YEARS OF SPACE

 

Black holes have been an endless source of fascination ever since Einstein’s Theory of General Relativity predicted their existence. In the past 100 years, the study of black holes has advanced considerably, but the awe and mystery of these objects remains. For instance, scientists have noted that in some cases, black holes have massive jets of charged particles emanating from them that extend for millions of light years.

These relativistic jets” – so-named because they propel charged particles at a fraction of the speed of light – have puzzled astronomers for years. But thanks to a recent study conducted by an international team of researchers, new insight has been gained into these jets. Consistent with General Relativity, the researchers showed that these jets gradually precess (i.e. change direction) as a result of space-time being dragged into the rotation of the black hole.

Their study, titled “Formation of Precessing Jets by Tilted Black Hole Discs in 3D General Relativistic MHD Simulations“, recently appeared in the Monthly Notices of the Royal Astronomical Society. The team consisted of members from the Anton Pannekoek Institute for Astronomy at the University of Amsterdam and a professor from the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) at Northwestern University.

 

much more at link.................

[pavelcherepan]

Simulations look great. I wonder why accretion disks end up being so very torus-like, rather than disks. I thought that due to conservation of momentum, they would flatten out. I need to read the study in detail.

[Mordred]

There is a lot of backreactions in play due to the extremes involved in the interparticle interactions under  hydrodynamics. Its a rather complex topic and requires a familarity with Euler hydrodynamic type equations to understand.