Visualization of a general relativistic collisionless plasma simulation. Image: Parfrey / LBNL
Researchers use one of the world's most powerful supercomputers to better understand how high energy plasma escapes the intense gravity of a black hole, which swallows everything else in its path-including light.
Before and after a black hole there's no return-a boundary known as the "event horizon" -and get consumed by the black hole, they get swept up in the black hole's rotation.
Physical Review Letters researchers affiliated with the Department of Energy at the University of California Berkeley used a supercomputer at the DoE's Lawrence Berkeley National Laboratory to simulate the jets of plasma, an electrically charged gas-like substance.
The first theory describes how electric currents circulate in a black hole. which is known as the Blandford-Znajek mechanism. This theory is getting closer to the horizon. The black hole acts like a massive magnetic field spinning in a huge magnetic field, which is causing an energy difference (voltage) between the poles of the black hole and its equator. This energy difference is now diffused as jets at the pole of the black hole.
The other theory describes the Penrose process, in which particles nearing a black hole's event horizon split apart.
"There is a region around a black hole, called the ergosphere," in this scenario, one half of the particle shoots out of the black hole. Kyle Parfrey, the lead author of the paper and a theoretical astrophysicist at NASA, told me in an email.
In other words, if one half of the split particle is launched against the spin of the black hole, it wants to reduce the black hole's angular momentum or rotation. But that rotational energy has to go somewhere. In this case, it's been translated into energy that propels the other half of the particle away from the black hole.
According to Parfrey, the Penrose process is considered to be different from what is described above, however. Rather than particles splitting, charged particles in the plasma are being acted upon by electromagnetic forces, some of which are propelled against the rotation of the black hole on a negative energy trajectory. It is in this sense, Parfrey told me that they are considered as a type of Penrose process.
Read More: Astronomers Discover Supermassive Black Hole Rotating at Half the Speed of Light
The surprising part of the simulation, Parfrey told me, that it appeared to establish a link between the Penford process and Blandford-Znajek mechanism, which had never been seen before.
In order to create the magnetic field of the black hole in the Blandford-Znajek mechanism, it requires the negative energy property characteristics of the Penrose process.
"So it appears, at least in some cases, the two mechanisms are linked," Parfrey said.
Parfrey and his colleagues hope that their models will provide much needed context for the photos from the Event Horizon Telescope, an array of telescopes that aim to directly image the event horizon , Parfery said he and his colleagues want to refine these simulations so that they conform even better to existing observations.