Good morning, all,
This item has got me thinking: I've read a few articles that in the past
laboratories have attempted to create chondrules, but failed.
Is anyone on the List familiar with what was the major obstacle, and is it
an endeavour that's still tried from time to time?
Cheers,
Pete
http://www.aip.org/enews/physnews/2006/split/767-3.html
Physics News Update
Number 767 #3, February 28, 2006 by Phil Schewe and Ben Stein
America's Hottest Lab
A temperature of 2 to 3 billion degrees Kelvin -- hotter than the interior
of any known star -- has been achieved in a lab in New Mexico.
The temperature record was set recently in a test shot at the Z Pinch device
at Sandia National Laboratory, where an immense amount of electrical charge
is stored in a device called a Marx generator. Many capacitors in parallel
are charged up and then suddenly switched into a series configuration,
generating a voltage of 8 million volts. The process captured in a famous
photograph, see Physics News Graphics.
This colossal electrical discharge constitutes a current of 20 million amps
passing through a cylindrical array of wires, which implodes. The imploding
material reaches the record high temperature and also emits a large amount
of X-ray energy (see PNU 702).
Why the implosion process should be so hot, and why it generates X-rays so
efficiently (10-15 percent of all electrical energy is turned into soft
X-rays), has been a mystery.
Now Malcolm Haines of Imperial College, in London, and his colleagues, think
they have an explanation. In the hot fireball formed after the jolt of
electricity passes through, they believe, the powerful magnetic field sets
in motion a myriad of tiny vortices (through instabilities in the plasma),
which in turn are damped out by the viscosity of the plasma, which is made
of ionized atoms.
In the space of only a few nanoseconds, a great deal of magnetic energy is
converted into the thermal energy of the plasma. Last but not least, the hot
ions transfer much energy to the relatively cool electrons, energy which is
radiated away in the form of X-rays.
Haines et al., Physical Review Letters, 24 February 2006
Contact Malcolm Haines, [EMAIL PROTECTED]
Image at Physics News Graphics
Back to Physics News Update
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