How to escape a black hole: Simulations provide new clues about powerful plasma jets

How to escape a black hole: simulations provide new clues about powerful plasma jets
This visualization of a general-relativistic collisionless plasma simulation shows the density of positrons near the event horizon of a rotating black hole. Plasma instabilities produce island-like structures in the region of intense electric current. Credit: Kyle Parfrey et al./Berkeley Lab

Black holes are known for their voracious appetites, binging on matter with such ferocity that not even light can escape once it's swallowed up.

Less understood, though, is how purge energy locked up in their rotation, jetting near-light-speed plasmas into space to opposite sides in one of the most powerful displays in the universe. These jets can extend outward for millions of light years.

New simulations led by researchers working at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley have combined decades-old theories to provide new insight about the driving mechanisms in the jets that allows them to steal energy from black holes' powerful gravitational fields and propel it far from their gaping mouths.

The simulations could provide a useful comparison for high-resolution observations from the Event Horizon Telescope, an array that is designed to provide the first direct images of the regions where the form.

The telescope will enable new views of the black hole at the center of our own Milky Way galaxy, as well as detailed views of other supermassive black holes.

"How can the energy in a black hole's rotation be extracted to make jets?" said Kyle Parfrey, who led the work on the simulations while he was an Einstein Postdoctoral Fellow affiliated with the Nuclear Science Division at Berkeley Lab. "This has been a question for a long time."

Now a senior fellow at NASA Goddard Space Flight Center in Maryland, Parfrey is the lead author of a study, published Jan. 23 in Physical Review Letters, that details the simulations research.

The simulations, for the first time, unite a theory that explains how electric currents around a black hole twist magnetic fields into forming jets, with a separate theory explaining how particles crossing through a black hole's point of no return—the event horizon—can appear to a distant observer to carry in negative energy and lower the black hole's overall rotational energy.

It's like eating a snack that causes you to lose calories rather than gaining them. The black hole actually loses mass as a result of slurping in these "negative-energy" particles.

This simulation shows a rotating black hole (bottom) and a collisionless plasma jet (top). The simulation shows the densities of electrons and positrons, and magnetic field lines. The black hole's "ergosurface," inside of which all particles must rotate in the same direction as the hole, is shown in green. Credit: Kyle Parfrey et al./Berkeley Lab

Computer simulations have difficulty in modeling all of the complex physics involved in plasma-jet launching, which must account for the creation of pairs of electrons and positrons, the acceleration mechanism for particles, and the emission of light in the jets.

Berkeley Lab has contributed extensively to plasma simulations over its long history. Plasma is a gas-like mixture of charged particles that is the universe's most common state of matter.

Parfrey said he realized that more complex simulations to better describe the jets would require a combination of expertise in plasma physics and the general theory of relativity.

"I thought it would be a good time to try to bring these two things together," he said.

Performed at a supercomputing center at NASA Ames Research Center in Mountain View, California, the simulations incorporate new numerical techniques that provide the first model of a collisionless plasma—in which collisions between charged particles do not play a major role—in the presence of a strong gravitational field associated with a black hole.

The simulations naturally produce effects known as the Blandford-Znajek mechanism, which describes the twisting magnetic fields that form jets, and a separate Penrose process that describes what happens when negative-energy particles are gulped down by the black hole.

The Penrose process, "even though it doesn't necessarily contribute that much to extracting the black hole's rotation energy," Parfrey said, "is possibly directly linked to the electric currents that twist the jets' magnetic fields."

While more detailed than some earlier models, Parfrey noted that his team's simulations are still playing catch-up with observations, and are idealized in some ways to simplify the calculations needed to perform the simulations.

The team intends to better model the process by which electron-positron pairs are created in the jets in order to study the jets' plasma distribution and their emission of radiation more realistically for comparison to observations. They also plan to broaden the scope of the simulations to include the flow of infalling matter around the black hole's event horizon, known as its accretion flow.

"We hope to provide a more consistent picture of the whole problem," he said.


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More information: Kyle Parfrey et al, First-Principles Plasma Simulations of Black-Hole Jet Launching, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.122.035101
Journal information: Physical Review Letters

Citation: How to escape a black hole: Simulations provide new clues about powerful plasma jets (2019, January 24) retrieved 24 April 2019 from https://phys.org/news/2019-01-black-hole-simulations-clues-powerful.html
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Jan 24, 2019
Amusingly the plasma ignoramuses finally think it's a good idea to include plasma physics in their explanation of this region composed of plasma.
And now they are discussing electric currents and "magnetic islands" (IOW's, plasmoids) to decipher the jets... Isn't that special.

Jan 24, 2019
Yeah, only a matter of days now until the whole world realizes the 200 EU proponents with 0 qualifications were right all along, much to their chagrin.

Jan 24, 2019
Amusingly the plasma ignoramuses finally think it's a good idea to include plasma physics in their explanation of this region composed of plasma.
And now they are discussing electric currents and "magnetic islands" (IOW's, plasmoids) to decipher the jets... Isn't that special.


Pillock. You have precisely zero plasma physicists in your Velikovskian cult. Idiot.

Jan 24, 2019
It's like eating a snack that causes you to lose calories rather than gaining them.

Popcorn has a similar effect!!!

Jan 24, 2019
Amusingly the plasma ignoramuses finally think it's a good idea to include plasma physics in their explanation...

It's nothing new; stuff like this has been going on even before most EU split-brain-experiment victims failed their first algebra exam.
________
Relativistic magnetohydrodynamical effects of plasma accreting into a black hole
R Ruffini, JR Wilson - Physical Review D, 1975 - APS
By an explicit analytic solution it is shown how, in the accretion of a poloidally magnetized
plasma into a Kerr black hole, a torque is exerted on the infalling gas, implying the extraction
of rotational energy from the black hole. The torque arises from the twisting of magnetic field

Jan 25, 2019
The torque arises from the twisting of the plasma disc around the non inertial black hole.
see: https://bigbang-e...out.html

Jan 25, 2019
You have precisely zero plasma physicists

Typical jonesdumb lie, it is one of the few ways he hangs his hat. Regardless of jonesdumb's inane blather the physics show electric currents and plasmoids drive this process. Take the BH away and the same is true, no fictional gravity monsters needed.

Jan 25, 2019
The gravitational 'escape V' at the Schwartzwald radii is 'c', but closer to the center of mass of the object, this 'escape V' rises to some maximum >>c at the centroid.

Buzz Aldrin once said that you could fly a brick if it had enough power. Notice all that negative energy in action around this black hole and its local effect on quantum units of space and its contained matter and energy there in the vicinity of this BH is direct observation that negative energy in much less than universal amounts could propel much smaller craft in Alcubierre space compression/expansion using self contained compact energy sources to travel great distances at warp speeds while the ship does not move in its protected bubble.

Jan 25, 2019
You have precisely zero plasma physicists

Typical jonesdumb lie, it is one of the few ways he hangs his hat. Regardless of jonesdumb's inane blather the physics show electric currents and plasmoids drive this process. Take the BH away and the same is true, no fictional gravity monsters needed.


Total crap. What is causing the observed orbits of the stars around Sgr A*? Come on, dummy, about time we had an answer. You've had plenty of time to invent some impossible woo or other. Let's hear it.

Jan 25, 2019
Strange no bullshit about how simulations are wrong from the EU ignoramuses.

Jan 25, 2019
Strange no bullshit about how simulations are wrong from the EU ignoramuses

Maybe you can point to where anyone claimed they were correct. The point offered merely is that, as the researcher claimed, that this is the first time plasma physics was included in the creation of the BH/jet simulation.

"Parfrey said he realized that more complex simulations to better describe the jets would require a combination of expertise in plasma physics and the general theory of relativity...
"I thought it would be a good time to try to bring these two things together," he said."

Wow! Must be a brilliant guy to have the temerity to suggest plasma physics might play a role in this region dominated by plasma.

But to your point, even though the sims resulted in the obvious and unavoidable conclusion that electric currents drive this process they are most certainly not valid in as much as they rely on a physics defying object (BH) as the source of energy.


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