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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.
by Robotbeat 4y ago
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.
- BeetleB 4y agoCan solid state lasers produce the high energy needed here?
- Robotbeat 4y agoYes. https://en.wikipedia.org/wiki/Laser_Inertial_Fusion_Energy#Mercury https://en.wikipedia.org/wiki/Laser_Inertial_Fusion_Energy#M...
- px43 4y agoI'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.
- Robotbeat 4y agoIt’s useful enough to produce significant net energy if they continue with the gain scaling that ignition allows.
- sillysaurusx 4y agoIt 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.) Good to hear that there's a laser design that might achieve that.
- nilsbunger 4y agoIt'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.
- simplicio 4y agoI 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.
- geysersam 4y agoExactly! 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.)
- ganbatekudasai 4y agoDon'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.
- sillysaurusx 4y agoNo thanks. I get that people are emotional about this, but it’s important to treat science with a critical eye. The claim is that more energy came out than was put in. This is false. It’s not just me saying it. https://www.tiktok.com/t/ZTRVP5Pmg/ https://www.tiktok.com/t/ZTRVP5Pmg/ 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.
- boc 4y ago
- sillysaurusx 4y agoWhich criticism am I dismissing? 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?
- CuriousCosmic 4y agoWorth 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.
- moloch-hai 4y agoThe theory was proven to everybody's satisfaction in 1950. There will be no production, except of new, smaller thermonuclear warheads. That is their legislated remit.
- kelnos 4y agoIt 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.
- worik 4y agoWhy are they using these "flash pumped" lasers if more efficient ones are available?
- jcarreiro 4y agoBecause 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.
- Aeolun 4y agoIs energy on the order of 300MJ so cheap? You’d think that cutting it down to 150MJ would allow them to do more experiments.
- nrki 4y ago300MJ ~= 83kWh which is like, $2000 in CA
- kragen 4y ago300 megajoules is 83 kilowatt hours 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 so this is about US$10 worth of electrical energy