Quasars, Why not?

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An Erratic Black Hole Regulates Itself
http://www.nasa.gov/mission_pages/chand ... 9-020.html

Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge.

"We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don't entirely understand, the other one gets the upper hand."

The latest Chandra results also show that the wind and the jet carry about the same amount of matter away from the black hole. This is evidence that the black hole is somehow regulating its accretion rate, which may be related to the toggling between mass expulsion via either a jet or a wind from the accretion disk. Self-regulation is a common topic when discussing supermassive black holes, but this is the first clear evidence for it in stellar-mass black holes.


Correlation between Plasma Dynamics and Emmision of Deuteron Beam, X-Rays and Neutrons in a Plasma Focus Discharge

Department of Electronic Engineering, Gunma University

(Received April 13, 1983; accepted for publication November 26, 1983)
The correlation between the plasma dynamics and the emission of a deuteron beam, X-rays and neutrons in a plasma focus discharge was investigated experimentally. The dynamics were observed using interferometry in the streak mode and framing mode, and the energy distribution of the deuteron beam was measured using a Thomson parabola analyzer. The plasma column was partially disrupted by the m=0 instability. The deuteron emission started some tens of nsec before the disruption of the plasma column, while the X-ray and neutron signals started some Lens of nsec after the disruption. The m=0 instability was observed in each discharge even if neutrons were not produced. It is concluded that the acceleration field of the ion beam giving the neutron yield is generated not by a rapid change in the plasma inductance but by an abrupt rise in the resistivity of the plasma.
The fine structure of the bubble formed in front of the current sheet propagating downstream was observed.

What is it that's different about these events aside from scale?
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