High-performance Plasmas May Make Reliable, Efficient Fusion Power A Reality

[Liffrea]

In the quest to produce nuclear fusion energy, researchers from the DIII-D National Fusion Facility have recently confirmed long-standing theoretical predictions that performance, efficiency and reliability are simultaneously obtained in tokamaks, the leading magnetic confinement fusion device, operating at their performance limits. Experiments designed to test these predictions have successfully demonstrated the interaction of these conditions.

http://www.sciencedaily.com/releases/2009/11/091102103327.htm

[Svipdag]

This report seems encouraging. If so, I'm tempted to say "About time !" I saw a demonstration of a tokamak 40 years ago. It produced pulses of thermonuclear fusion having a duration of a few microseconds, accompanied by a few neutrons which proved that fusion was actually occurring. WOW !

Progress has been so slow since then that I have despaired of seeing a thermonuclear reactor produce usable quantities of electric power during my lifetime. Considering my age, I still doubt it. If I understand the article and am not reading wishful thinking into it, contrary to expectation, high-density plasmas are less prone to plasma instabilities than low-density plasmas.

That has always been the big problem. The 10,000,000 degree plasma must NOT touch the wall of the confinement vessel. It must be confined by a toroidal magnetic field. However, the flowing plasma produces its own magnetic field which interacts with the confining field . As long as the flow of the plasma is essentially laminar, all is well, but the interaction between the
two magnetic fields tends to set up eddies, or instabilities which break down the magnetohydrodynamic coupling between the plasma and the confining field .

The plasma breaks out of its magnetic "bottle" and touches the wall. If the plasma density is low, it does not melt or vapourise the wall but just gives up heat to it so that the plasma is too cold for fusion to occur. It was expected that denser plasmas would be even more unruly and would destroy the tokamak. Apparently, this has been found not to be true.

Perhaps, there IS a light at the end of the tunnel that is not the light from a melting tokamak.

[Octothorpe]

This sounds hopeful, but I keep thinking of all the times I've heard that 'fusion is just around the corner.' I'll believe it when GE starts selling them to my local power provider.

[Svipdag]

In the meantime we might do more about using energy from a thermonuclear reactor which we KNOW works, the one which we can see almost every day.
Even though 93,000,000 miles away, it supplies an enormous amount of energy which we aren't using.