That’s only because they’re using old school flash pumped lasers, not the new solid state lasers you’d use today if you wanted to make a power plant demo.
I'm not really seeing any convincing numbers there. Mercury lasers seem to only be 10% efficient. I get that this is better than the lasers that were just used at NIF, but that still seems pretty far from useful.
Because they are researching inertial confinement fusion, not trying to build a working power plant. The efficiency of the lasers doesn't matter, since it doesn't affect their research.
a typical power price at trading hubs is US$40 per megawatt hour, though this varies considerably depending on many factors and is sometimes actually negative
a typical retail price is US$120 per megawatt hour
I think you're out by some orders of magnitude. With the current energy issues in the UK it'd be under £100. Other things suggest in California it's more like 20 cents per kWh so were you thinking ~$20?
It's a very old lab, and replacing them isn't cheap/easy.
You don't need to use efficient lasers to get the scientific results they're after - other people have already very accurately measured the properties of modern lasers, so we can predict how they would perform without having to actually use them.
That's not the purpose of the research, though. They are solely focusing on the energy transfer between the lasers themselves, and the output from the reaction. It's not clear that higher energies or bigger targets will teach us anything new.
Upgrading the lasers would slow the project down as new hardware is installed and issues are worked out. Not to mention I doubt the new hardware is cheap, and may be more expensive than burning excess energy using old laser tech in the meantime.
Other research groups work on laser efficiency, and the "final product" using this method (if it ever proves viable) would put together all the best pieces to get the best efficiencies.
The electricity bill is like $2000. It'd waste more money for a manager to think about how to replace equipment, at California pay rates. This whole thread is making me lose faith in HN.
Don't take it too personally, but you, and many others here, need to rethink their approach. You see a short tweet without context about a topic you clearly know nothing about (which is totally, fully okay, it's a complex topic), and think you are now able to criticize milestones in this impossibly complex topic.
Not even ask questions, not something like "hey, I saw this tweet, I know it's just a tweet, but can someone help me understand context?", no, you actually go ahead and criticize work that you know nothing about, and when confronted, you double down.
On some level, you must know yourself that it might be better to ask as many unloaded questions as you want, but otherwise sit this one out in terms of assessment.
There is no “context” to understand. Yes, it’s an impressive feat. Yes, other laser designs might fix the huge ignition costs. But that hasn’t happened yet, and until it does, it’s completely fair to point that out.
Will it win me any friends? Probably not. It’s like showing up to a party and saying the reason for the party is mistaken. Very few people care.
But scientists should, and I am one. Doubly so for incorrect reporting to laymen. We have a responsibility to convey what was actually achieved, not what we wish was achieved.
People do seem to be getting emotional about fusion, and pointing that out is hardly edgy.
Once fusion achieves more output than input, I’ll be celebrating right there with you. But until then, ignoring the Doberman in the room is a worse look, from a scientific standpoint.
I even cited a source from someone with a phd in mathematical physics, who is likely far more qualified to be talking about this than most of us here. So in terms of dismissing criticism, the stack seems to be in the other direction.
Scientific reporting matters. Reporting something false is generally a bad idea. Saying “we got more energy out than we put in” is false. Which link in this chain of reasoning is invalid?
> It just seems a little strange to take credit for a milestone when the milestone everyone cares about is yet to be reached. (More energy out than in.)
That comment/criticism is a little strange in and of itself. I would say it's the oddness or seeming petulance of the above comment that brought on boc's comment.
A silly, but illustrative analogy:
Kid: Dad, look! I scored a home-run!
Father: Who cares? Have you won the game yet? Stop celebrating until you do something that everyone cares about!
I agree.
To explain further, my post and the included (noted silly) analogy were made with respect to explaining the aspect of sillysaurusx's post(s) that boc seemed to be criticizing.
Your "honest feedback" is nothing more than naked insults.
Sillysaurusx is right. The "impossibly complex" matter is actually quite simple, Q=1 is little more than a psychological milestone, not some sort of technical tipping point where further progress becomes easier. And they haven't even gotten to Q=1 unless you buy into the justifications they give for dodgy accounting of the energy they put into it. The "impossibly complex" matter of commercial fusion is actually quite simple, it needs to put out a lot more energy than you put into it after you fully account for all the energy you put in. They aren't even close to this.
When a baseball batter hits a ball at a record 120mph, you calculate the impulse of force (∆p) they put into the swing to cause that result, not the total calories the player consumed during the past year in order to build their muscles.
You're arguing that the process of charging some inefficient lasers (aka eating food throughout the year) is invalidating this entire result. That was never part of the experiment, nor is it relevant to this test.
I understand exactly what you wrote above, and I'm telling you that it's not relevant to this discovery. You're arguing a non-sequitur in the classic definition.
Just as a note, since I made the same mistake initially, the person you're replying to didn't make the post from which you are quoting "impossibly complex".
It seems, to me, that boc was criticizing the unnecessarily dour tone of sillysaurusx's previous comment and not the technical aspect of the achievement.
The whole thing seems to come down to whether one interprets the announcement as an attempt to deceive the public at large or simply a celebration of a milestone that many in the fusion research community have been trying to achieve for a long time. I can understand it being interpreted both ways, but I think the more charitable interpretation is that science reporting, in general, doesn't usually properly explain the levels of nuance of various achievements and, as such, something that is genuinely exciting for those in the community is not necessarily as exciting for those outside of it - which comes across as deceptive.
You are entirely correct. I'll just add that it's not only about the energy put in, but ultimately about the cost.
Net positive energy output is the absolute basic requirement. We're not there, we're not close, and even if we were, the hurdle would be to make it economically viable.
I think the confusion here is at least partially due to most articles obscuring the primary purpose of the NIF. Its not supposed to support commercial energy development, its supposed to support nuclear weapons development under the Nuclear Test Ban Treaty, where testing bombs via setting them off is banned.
So the NIF is supposed to give a testbed to study implosion created fusion reactions that produce enough energy to "ignite", that is, propegate the reaction to the rest of a hypothetical bomb. In that case, the amount of energy needed for the infrastructure to produce the initial implosion doesn't matter, what matters is that the energy coming out is more then the actual energy that triggered the reaction, so that the hypothetical bomb would blow up and not fizzle.
Exactly! It's so strange this is somehow made to be about fusion as an energy source.
I'm happy to announce that Q>>1 has already been achieved on multiple occasions. In the cores of the thermonuclear devices tested by the US and USSR in the 50s.
(Unfortunately that technology proved unviable as a path to civilian fusion power.)
It is a milestone, and I do think the researchers deserve credit for that. Getting more energy out of the reaction than was delivered to it by the lasers is actually important.
No one (except perhaps poor science "reporters") is claiming that this means we now have free and cheap fusion power. Of course the energy put in to operate the lasers themselves needs to be accounted for -- and it is! -- but that doesn't make what they've achieved useless. It's also useful to remember that the researchers involved are not the people writing press releases and articles; let's not minimize their achievement just because of sloppy, sensationalist reporting.
I like the analogy downthread of a kid being excited about scoring a home run in baseball, but the dad chastising the kid for celebrating before actually winning the game. That's what it feels like is happening here.
This is a huge step in the right direction, and it should be celebrated as such.
It's a significant milestone because demonstrating you can get net energy from the reaction removes a lot of uncertainty of whether it's possible in the real world. It starts to turn inertial fusion into an engineering problem of how you increase the efficiency of each stage.
Worth noting that the milestone achieved was positive Q_plasma (more energy out of the plasma than in).
They are using inefficient lasers because they are cheaper to buy/maintain/modify for research purposes.
Determining the conditions for positive Q_plasma is largely a matter of science/research so the external system doesn't matter as long as the variables are controlled and results are reproducible.
Once positive Q_plasma is well understood/reproducible, achieving positive Q_total (more energy produced than spent running the infrastructure) is just a matter of engineering and potentially waiting for the SOTA for components (like lasers or materials) to catch up.
TLDR: This is the scientists proving the theory. Now it's the scientists' job to refine the theory. Then the engineers get to put it into production.
