From SLAC Today: “KIPAC Study Sheds Light on Cosmic Jets”

April 30, 2012
David Reffkin

“The cosmos contains particle accelerators that are much more powerful than our biggest machines. They are powered by black holes and their surrounding disks of matter, called accretion disks. As matter swirls into the black hole, the interaction emits enormous jets of particles and radiation traveling at nearly the speed of light.

The commonly accepted theory for the development of the jets is called the Blandford-Znajek Mechanism, named for Roger Blandford and Roman Znajek. Blandford, a physics professor at Stanford, also directs the Kavli Institute for Astroparticle Physics and Cosmology (KIPAC), which is jointly run by SLAC and the university.

In 1977, the scientists suggested that part of the energy needed to accelerate the particles is extracted from the rotational energy of the hole. However, there are still many details to learn about the process that launches such enormous jets of energy.

Because these cosmic accelerators are far away, and because the accretion disk of matter surrounds the black hole, the launching of the jets can’t be seen directly. Enter simulations, which allow scientists to probe the extreme physics within these systems by entering the initial conditions into a computer and allowing systems to evolve according to the relevant physics.”

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Visualization of a simulated vertical slice through an accreting disk of matter around a black hole. Mass of varying density (blue is low, red is high) is pushing through the magnetic field (black lines) into the hole. Image courtesy KIPAC

See the full article here.

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
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