Originally posted by twhitehead
The issue isn't 'how much current can you squeeze through it'. After all, you can just add more coils. The issue previously was that superconductors tended to stop working if the magnetic field went over a certain strength. In this design the limits are not being pushed as far as current is concerned so no need for more current.
There would be an issue with size however, if you have to increase the coil length and such, the whole affair gets bigger and would defeat the purpose. The other issue would be the support structure which seems to have to withstand some 5000 atmospheres of magnetic pressure. That is about 150,000 PSI, a healthy stress! If the magnetic field doubled again and the stress was linear, we would be talking 300,000 PSI and that in turn could mean twice the metal to withstand that force. If so, the plasma core could get smaller at the expense of making the support structure twice as large and twice as heavy so it would seem to have a limiting factor there unless much stronger metals were developed that was both non magnetic and twice as strong as the metal used for this project.
If it succeeds it may be about as small as you can physically make a reactor like that, at least for magnetic confinement. It will take some doing to get inertial systems (lasers) to get much smaller than they are now assuming they can go beyond mere ignition into high Q territory.
It's really weird to think of the plasma, it wants to be at some number higher than atmopshere, I forget the actual number, 10 atmospheres maybe, but surrounded by a good vacuum. Quite a trick. And then keep it at 100 million degrees for some significant amount of time and extract the heat to go to a traditional heat exchanger/turbine affair.
ITER seems hidebound and unable to use the latest technologies of superconductors much less replaceable parts.
They are going to have major egg on their face if the MIT crew succeeds for a few hundred million when ITER is bleeding money by the billions.