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It Has Beams

Posted: Mon Jun 09, 2008 4:10 pm
by MSimon
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http://news.bbc.co.uk/1/hi/sci/tech/1573450.stm


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Image

You know, I don't think it is something they want in that type of machine.
Controlling the eddies and whirls of the writhing plasma so that it can burst into life as a miniature Sun has been a formidable, and so far only partially met, engineering challenge.
:-)
"If we follow the Mast idea and not the Jet one, we could imagine a string of medium-scale fusion reactors instead of a few very big ones," said Dr Sykes.

"There are still very many difficulties but perhaps in a few decades we could have commercial fusion reactors in cities providing cheap pollution-free power," he added.
Perhaps we will.

Posted: Tue Jun 10, 2008 1:14 am
by rj40
In just a few short decades! 4 or 5 I'll bet.

I notice they call it a spherical tokamak. Do you think polywell would get more funding if it was called that?

I wonder how many "few short decades" fusion ideas have explanations similar to this:

http://asuwlink.uwyo.edu/~jimkirk/guidance.wav

I can see a politician throwing money at someone like this.

A classic.

Posted: Wed Jun 11, 2008 10:08 am
by Keegan
The best approach appears to be to confine a superhot gas, called a plasma, in a magnetic field
Plasmas in magnetic fields generate cyclotron radiation.

Confining ions in concave magnetic fields is extremely difficult.

FAIL.
As nuclei fuse, a vast amount of energy is released
So is a sea of Deadly destructive Nuetrons, released by Tokamaks burning DD, DT as these are the only fuels they can burn with their low power densities.

FAIL.


A public service anouncement.


Polywells have a high power density, capable of burning clean advanced fuels such as p + B11, with the reaction space ingeniously uninfluenced by magnetic fields.

Posted: Fri Jun 13, 2008 7:47 am
by jmc
I'm still not convinced about this whole p-B stuff. And I'm not convinced the Polywell can maintain the electrons at a significantly lower temperature than the ions. There's nothing wrong with producing neutrons as long as you can shield it appropriately during operations which can be done.

Confining ions in any magnetic field is extremely difficult, including a cusp field. Keeping them out of maxwellian equilibrium at fusion relevant densities and confinement times is more difficult still.

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On a more positive front in the MAST spherical tokamak at Culham many of the coils are inside the vacuum vessel rather than outside as is the case with many other tokamaks. This means that much of the expertise required to run, say, a scaled up turnkey polywell with an inner magrid already exists in Culham.