You can't expect exponential progress to continue forever in the world of atoms, so I disagree with your characterisation of "bleak". After all, that doesn't happen in any other non-software industry
I don't have the knowledge to judge how much of this slowdown is due to the ITER project being international and difficult to manage, and how much of it is due to us approaching the limits of what is physically possible.
However it's good to keep in mind that our level of funding for fusion is pathetic and scientists themselves have categorised it as "fusion never"
I don't think the atoms point is right. Silicon semiconductors are made of atoms. Also, we get Moore's law like behavior in lots of very physical industries, e.g., the cost of solar panels.
A pretty simple model that accounts for the data is that Moore's law, and many other exponential growth examples, require ever larger capital expenditures. This worked for Moore's law because at ever step of improvement the devices produced were highly economically valuable. For fusion, on the other hand, you can have an exponentially improving triple product, but it has zero economic value until you cross the net-positive threshold. That basically means that the exponentially increasing development funding needs to be provided by the government, philanthropy, or some other non-profit source. If you're exponentially improving, with exponential costs, and you hit the ceiling of what the government and philanthropists are willing to provide, your progress can come to an abrupt halt without it necessarily meaning the basic exponential engineering curve you were following stops.
I think the parallel between cost of semiconductor fabs increasing and costs of fusion reactors increasing is quite apt.
But we don't actually have exponential improvement in any physical object, that's not to do with information processing - a solar panel or battery made today is not 10x better than one made 10 years ago.
It's not even true of all semiconductors - power electronics, radio, etc.
> But we don't actually have exponential improvement in any physical object, that's not to do with information processing - a solar panel or battery made today is not 10x better than one made 10 years ago.
Do you understand how differently that reads from your original comment?
> Fusion has advanced faster than Moore's law - and unlike the holy grail of computing, true AI, it's now clearly within reach.
You made the claim it's advancing at a rapid rate and almost here, and when someone pulled up the data it wildly disagreed with you. Now you're just moving the goalposts.
Here's what Robert Zubrin has to say about this graph in his latest book "The case for space" (p174):
"The national fusion programs progressed well during the Cold War because of fierce international competition. They have stopped moving forward in the late 1980s because the decision to consolidate them all into a single global project, the International Thermonuclear Experimental Reactor (ITER), removed all stimulus for action. Indeed, it too, nearly a quarter century for the bureaucrats in charge of ITER to manage to reach a consensus in 2010 on where tu put it, and it will be another quarter century before the machine even attempts to reach thermonuclear ignition in 2035"
That seems like a just-so story to me. It's not like all the smaller fusion research programs stopped existing, the US for example still had the NIF running in parallel, with substantial funding. It's just that it appears that a very large scale project is needed to get above unity fusion with the tocamac approach.
I seem to remember that NIF is focused on nuclear weapons research. Which very likely means that most of the results they produce are highly classified, so of limited usefulness for the rest of the world's scientific community.
Sure that is their main focus but I think they also have a fusion power component in their research. The point was more generally that the inception of ITER did not mean the end of all other smaller fusion research programs, as Zubrin seems to imply.
Judging from the end of this comment chain, the SPARC reactor from Commonwealth Fusion Systems (targeting ignition in 2025) will likely be around the ITER Target on that plot:
Edit: https://www.sciencedirect.com/science/article/pii/S254243511...
Figure 1 has an updated version, and it is rather bleak.