In recent years, two Caltech researchers have been modeling magnetic activity on the Sun by using a stainless steel vacuum chamber called a spheromak. The device was developed primarily to study nuclear fusion, the process that powers the Sun and which has been studied as a possible source of terrestrial power. The scientists, Scott Hsu and Paul Bellan, have now figured out how to employ the spheromak to mimic a black hole's jets.

They use magnetic energy to harness plasma into jets that they say share many of the characteristics of black hole jets. They will report their research tomorrow at an annual meeting of the American Physical Society's Division of Plasma Physics in Orlando, Fla.

The whole experiment goes on in a cylinder the size of a large closet. Though the device and the result both involve complex physics, little coaxing is needed for the jets to form, it turns out.

"Photographs clearly show that the jet-like structures in the experiment form spontaneously," Bellan said.

The lab device uses voltage differences between two electrodes to create magnetic field lines that simulate an accretion disk in a plasma of hydrogen. The current applied is tens of thousands of times more powerful than what runs your toaster.

The work supports a theory about the real astrophysical jets.

The idea is that jets can form when magnetic fields are twisted by the rotation of an accretion disk, the name given to a rotating and relatively flat disk in which matter spirals inward toward a black hole. Once inside a black hole, matter is trapped. But on the way in, as it approaches the speed of light, much of the matter is converted to plasma, and not all of it seems to pass through the so-called event horizon, a sphere of no return.

Magnetic forces are said to squeeze some of this plasma and the magnetic energy embedded in it into narrow jets that shoots out along the axis of rotation. (A study last year showed that black holes themselves probably rotate.

None of this can actually be observed developing around supermassive black holes, because the process can't be measured in human time scales. We. re talking about galaxies that are billions of light years away and took billions of years to evolve.

However, astronomers have witnessed the outlines of such actions in the environments surrounding stellar black holes, objects within our own galaxy though to have formed when massive stars collapse.

In June, scientists reported that the jets from stellar black holes are indeed related to the accretion disks. And earlier this month, a research team revealed a remarkable set of observations detailing the entire life cycle of a jet emanating from a stellar black hole.

Hsu and Bellan say the spheromak jets also develop wiggles, scientifically called helical instabilities, that have been observed in black hole jets as well.

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