[SiempreViernes]

The claim isn't that there is only one way to build fusion reactors, the claim is simply that there is only one well-developed design.

Small prototypes don't mean immediate progress in fusion, the original tokamak was hailed as great progress in 1958 and it was less than a metre across.

Until we have perfect understanding of Magnetohydrodynamics and materials science one simply cannot reliably predict the behaviour of completely new devices.

[cromwellian]

These prototypes aren't scaled down versions of ITER, the field strength of ARC is of the same magnitude of ITER, it's capable of the same pressures and confinement, only in a much smaller volume.

It's like saying a 5nm CPU design is somehow the same as a 32nm CPU, even if they both had the same die size, even those the 32nm versions had far less transistors.

[SiempreViernes]

I never said they were versions of ITER, my point was that the new prototypes themselves need to do most of the upscaling work that's gone into tokamaks. As for Arc, that's simply a tokamak that can't be built yet because the tech isn't ready, not sure what that is supposed to contribute, did you read the rest of this thread?

To summarize:

. <-- the point

                             --> your comment

[cromwellian]

Which tech isn't ready? The plasma behavior for that volume was already shown by JET @ 1.5 bar. MIT Alcator C-Mod which achieved a record 2-bar pressure that won't be beaten by ITER for 15 years. Arc also predicts a 2-bar pressure plasma. The difference is, they did it with non-superconducting magnets (copper), and paid a huge price in losses due to resistance. Arc's HTS magnets won't suffer the same problem, will have triple the field strength, and will be structurally stronger.

Arc is doing what JET and Alcator C-Mod did (with a radius very similar to JET), just with a much more power efficient confinement system, so the input power is lower, and the magnetic field is a factor of 2.6 stronger. The basic physics show that stronger fields actually make the plasma more well behaved, not less, so the major variable vs JET (a proven existing tokamak with Q=0.67) that's changing is not likely to lead to surprising results.