Building a tokamak fusion power plant is not a scientific problem, but an engineering one. 
The science works and says for a stable plasma with the temperature & density gradients at the edge manageable, then the device needs to be very big.  ITER is just about the smallest size that can achieve Q>1.

Just because the first ‘candle’ of fusion needs to operate on a scale larger than our everyday human interactions should not surprise us.  Its still a lot smaller than the Sun.

If we only invested in things that already work, there would be no laser, transistor, generators etc. Before there was a “first car that moved slowly” there was a bunch of internal combustion engines that didn’t work at all. You just don’t remember them or care about them. But without that R&D there would be nothing to remember! 

Did you know that one of the first internal combustion engines that was proposed used gun powder!

jamesr - 23 September 2011 04:45 AM

Building a tokamak fusion power plant is not a scientific problem, but an engineering one. 
The science works and says for a stable plasma with the temperature & density gradients at the edge manageable, then the device needs to be very big.  ITER is just about the smallest size that can achieve Q>1.

Just because the first ‘candle’ of fusion needs to operate on a scale larger than our everyday human interactions should not surprise us.  Its still a lot smaller than the Sun.

Perhaps we could modify our “energy (in)efficiency” poster on this page (scroll down when you get there) to show the possibilities of ITER.  We want a star on earth, without all that mass.  And think how much more efficient it is than the sun.  It’s like indoor skiing. 

To ski, you don’t need a mountain, you just need a slope. 

Likewise, for the fusion alternatives, you don’t need to gut the mainline fusion approaches.  You need to come up with an assessment of how much money and resources you need, and then look for a diverse revenue base to fund that. 

It’s good that stars burn their fuel so slowly.  This comes from the fact that the fusion cross-section for normal proton-proton fusion is around 20 orders of magnitude smaller than for D-T (since it has to rely on the weak nuclear force, rather than the strong force).

Trying to contain D-T fusion is more like trying to contain a Supernova!