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I guess we should take this as a lesson in communications. The "breakeven" thing is a red-herring that should have been have been left out of the message, or a

by floxy 4y ago

I guess we should take this as a lesson in communications. The "breakeven" thing is a red-herring that should have been have been left out of the message, or at least only mentioned as a footnote. The critical ELI5 message that should have been presented is that they used a laser to create some tiny amount of fusion. But we have been able to do that for a while now. The important thing is that they were then able to use the heat and pressure of the laser generated fusion to create even more fusion. A tiny amount of fusion creates even more fusion, a positive feedback loop. The secondary fusion is still small, but it is more than the tiny amount of laser generated fusion. The gain is greater than one. That's the important message. And for the future, the important takeaway is that the next step is to take the tiny amount of laser fusion to create a small amount of fusion, and that small amount of fusion to create a medium amount of fusion. And eventually scale it up enough that you have a large amount of fusion, but controlled, and not a gigantic amount of fusion that you have in thermonuclear weapons, or the ginormous fusion of the sun.

jboy55 4y ago
and not a gigantic amount of fusion that you have in thermonuclear weapons, Ironically, this experiment was designed primarily to simulate the fusion you have in thermonuclear weapons. That's the NIF's purpose and the purpose of this experiment. From Nature https://www.nature.com/articles/d41586-022-04440-7 https://www.nature.com/articles/d41586-022-04440-7 "Herrmann acknowledges as much, saying that there are many steps on the path to laser fusion energy. “NIF was not designed to be efficient,” he says. “It was designed to be the biggest laser we could possibly build to give us the data we need for the [nuclear] stockpile research programme.”
- dmix 4y ago
  From what I can tell this is mostly a useful cover story as a fallback for the moon-shot type energy potential. But are there serious downsides to having this be the case? Does it significantly distract away from the pursuit of energy? Or somehow fundamentally constrain the projects scope?
  - moloch-hai 4y ago
    Exactly the opposite: their task, assigned by Congress, is weapons work. Period. But pretending to work on "carbon-free energy" is good for funding, just now. Four years ago, being all about weapons opened the tap. Make no mistake, there is no story here. There will be no "unlimited free energy" from this, or any other fusion project. The fusion startups are spending down investors' money with zero possibility of payback (Helion conceivably excepted), because if they did get Q>1, they have no workable way to harness it. ITER will not even try to produce one watt-second of electricity. Its follow-on demo reactor won't start building until 2050, if not further delayed. We know the way to get unlimited free energy: solar. Build more, get more. It doesn't have bomb scientists making inflated claims; it just works, and better every year.
    - jboy55 4y ago
      At least ITER has a plausible, in a sci-fi story sense, way of creating a sustainable fusion reaction to which more fuel could be given. The fact the neutrons produced, if it did reach the high Q ratios, would irradiate and break down everything involved, is probably 2070's scientists and engineers problems to solve.
      - moloch-hai 4y ago
        In that paradise of abundant cheap solar and wind power, only weapons people will be interested in fusion. They will probably be trying to come up with zero-fallout things they can use tactically.
        zbobet2012 4y ago
        Solar and wind power are not sufficient for spacecraft, and many other applications. Fusion power still has very interesting applications.
        moloch-hai 4y ago
        Most likely, spacecraft will rely on power delivered via laser. If anybody succeeds in working out D-3He fusion, that could work in a spacecraft. (D-T, no.) We could probably scare up enough 3He to use for that, if there weren't too many.
- _cs2017_ 4y ago
  How would it help build better weapons? I thought the existing thermonuclear bombs do the job perfectly fine. Sure, the military might want to make them a bit smaller or a bit cheaper, but is it really such a big deal as to warrant a major announcement?
  - jacquesm 4y ago
    Given the limitations on nuclear research for weapons purposes any information that can be gleaned from these experiments that is 'dual use' is more than welcome with the parties that are currently stymied by various arms control agreements. This is also why you will see a lot of supercomputer capacity near such research, it allows simulation of experiments with high fidelity rather than the experiments themselves. These are all exploitation of loopholes. The biggest value is probably in being able to confirm that the various computer models accurately predict the experimental outcomes. This when confirmed at scale will allow for the computer models to be used for different applications (ie: weapons research) with a higher level of confidence.
    - _cs2017_ 4y ago
      Presumably these computer models are mostly useful for creating new designs (since the old designs were proven by real tests). Would such new designs be convincing enough to the adversary to fulfill its role as a strategic deterrence? When (in XX years?) almost all US nukes are only simulated on computers and not actually tested, the Russians may start wondering if the US aresnal actually works, no? That would be a horrible outcome, since it means the Russians would be taking somewhat greater risks in their decision-making. Wouldn't far outweigh any opertaional or financial benefits the newer designs offer? I suppose one could argue that if the loss of confidence in strategic weapons matched the actual loss in reliability, it might be a "no op" (although even this is arguable). But if the Russians think the US simulations suck, while the US is actually building really good simulations, the loss of confidence would be greater than the actual loss in reliability. In the extreme case, the nukes work great, but everyone thinks they are scrap metal. Of course, the same happens in reverse: if the Russians are upgrading their weapons to untested designs, the US may start underestimating the risk.
lazide 4y ago
Eh, the ‘mistake’ was intentional, near as I can tell.
eru 4y ago
> [...], or the ginormous fusion of the sun. The sun actually has very little fusion per cubic metre or per kg. Per volume the core of the sun produces only a quarter of the heat of the human body (and per kg it's even less, owing to high density). That's why our fusion reactors can't just mimic stars, they have to far surpass them to be useful to us.
- aoetalks 4y ago
  This is incredible.
  - eru 4y ago
    To give some more detail: hydrogen to helium fusion (even with intermediate steps) is extremely unlikely to happen. That's part of why the sun will last for billions of years. And that's also why first human attempts at fusion are not trying to use straight up hydrogen as the fuel. Good old Wikipedia has this gem: > The large power output of the Sun is mainly due to the huge size and density of its core (compared to Earth and objects on Earth), with only a fairly small amount of power being generated per cubic metre. Theoretical models of the Sun's interior indicate a maximum power density, or energy production, of approximately 276.5 watts per cubic metre at the center of the core,[63] which is about the same power density inside a compost pile. https://en.wikipedia.org/wiki/Sun#Core https://en.wikipedia.org/wiki/Sun#Core Another fun fact: there's a decades old design for a gadget that fits at the top of your desk and does nuclear fusion. You could build one yourself, if you are sufficiently dedicated. Unfortunately, no one has ever worked out how to run one of them as a power plant. Ie how to get more useful energy out than you have to put in. https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor
    - deleted 4y ago
      [deleted]
    - PaulHoule 4y ago
      Those Fusors can make a decent neutron source however. Those were invented by Philo Farnsworth, who invented the cathode ray tube for television.

by floxy 4y ago

jboy55 4y ago

and not a gigantic amount of fusion that you have in thermonuclear weapons, Ironically, this experiment was designed primarily to simulate the fusion you have in thermonuclear weapons. That's the NIF's purpose and the purpose of this experiment. From Nature https://www.nature.com/articles/d41586-022-04440-7 https://www.nature.com/articles/d41586-022-04440-7 "Herrmann acknowledges as much, saying that there are many steps on the path to laser fusion energy. “NIF was not designed to be efficient,” he says. “It was designed to be the biggest laser we could possibly build to give us the data we need for the [nuclear] stockpile research programme.”

dmix 4y ago
From what I can tell this is mostly a useful cover story as a fallback for the moon-shot type energy potential. But are there serious downsides to having this be the case? Does it significantly distract away from the pursuit of energy? Or somehow fundamentally constrain the projects scope?
- moloch-hai 4y ago
  Exactly the opposite: their task, assigned by Congress, is weapons work. Period. But pretending to work on "carbon-free energy" is good for funding, just now. Four years ago, being all about weapons opened the tap. Make no mistake, there is no story here. There will be no "unlimited free energy" from this, or any other fusion project. The fusion startups are spending down investors' money with zero possibility of payback (Helion conceivably excepted), because if they did get Q>1, they have no workable way to harness it. ITER will not even try to produce one watt-second of electricity. Its follow-on demo reactor won't start building until 2050, if not further delayed. We know the way to get unlimited free energy: solar. Build more, get more. It doesn't have bomb scientists making inflated claims; it just works, and better every year.
  - jboy55 4y ago
    At least ITER has a plausible, in a sci-fi story sense, way of creating a sustainable fusion reaction to which more fuel could be given. The fact the neutrons produced, if it did reach the high Q ratios, would irradiate and break down everything involved, is probably 2070's scientists and engineers problems to solve.
    - moloch-hai 4y ago
      In that paradise of abundant cheap solar and wind power, only weapons people will be interested in fusion. They will probably be trying to come up with zero-fallout things they can use tactically.
      - zbobet2012 4y ago
        Solar and wind power are not sufficient for spacecraft, and many other applications. Fusion power still has very interesting applications.
        moloch-hai 4y ago
        Most likely, spacecraft will rely on power delivered via laser. If anybody succeeds in working out D-3He fusion, that could work in a spacecraft. (D-T, no.) We could probably scare up enough 3He to use for that, if there weren't too many.
_cs2017_ 4y ago
How would it help build better weapons? I thought the existing thermonuclear bombs do the job perfectly fine. Sure, the military might want to make them a bit smaller or a bit cheaper, but is it really such a big deal as to warrant a major announcement?
- jacquesm 4y ago
  Given the limitations on nuclear research for weapons purposes any information that can be gleaned from these experiments that is 'dual use' is more than welcome with the parties that are currently stymied by various arms control agreements. This is also why you will see a lot of supercomputer capacity near such research, it allows simulation of experiments with high fidelity rather than the experiments themselves. These are all exploitation of loopholes. The biggest value is probably in being able to confirm that the various computer models accurately predict the experimental outcomes. This when confirmed at scale will allow for the computer models to be used for different applications (ie: weapons research) with a higher level of confidence.
  - _cs2017_ 4y ago
    Presumably these computer models are mostly useful for creating new designs (since the old designs were proven by real tests). Would such new designs be convincing enough to the adversary to fulfill its role as a strategic deterrence? When (in XX years?) almost all US nukes are only simulated on computers and not actually tested, the Russians may start wondering if the US aresnal actually works, no? That would be a horrible outcome, since it means the Russians would be taking somewhat greater risks in their decision-making. Wouldn't far outweigh any opertaional or financial benefits the newer designs offer? I suppose one could argue that if the loss of confidence in strategic weapons matched the actual loss in reliability, it might be a "no op" (although even this is arguable). But if the Russians think the US simulations suck, while the US is actually building really good simulations, the loss of confidence would be greater than the actual loss in reliability. In the extreme case, the nukes work great, but everyone thinks they are scrap metal. Of course, the same happens in reverse: if the Russians are upgrading their weapons to untested designs, the US may start underestimating the risk.

lazide 4y ago

Eh, the ‘mistake’ was intentional, near as I can tell.

eru 4y ago

> [...], or the ginormous fusion of the sun. The sun actually has very little fusion per cubic metre or per kg. Per volume the core of the sun produces only a quarter of the heat of the human body (and per kg it's even less, owing to high density). That's why our fusion reactors can't just mimic stars, they have to far surpass them to be useful to us.

aoetalks 4y ago
This is incredible.
- eru 4y ago
  To give some more detail: hydrogen to helium fusion (even with intermediate steps) is extremely unlikely to happen. That's part of why the sun will last for billions of years. And that's also why first human attempts at fusion are not trying to use straight up hydrogen as the fuel. Good old Wikipedia has this gem: > The large power output of the Sun is mainly due to the huge size and density of its core (compared to Earth and objects on Earth), with only a fairly small amount of power being generated per cubic metre. Theoretical models of the Sun's interior indicate a maximum power density, or energy production, of approximately 276.5 watts per cubic metre at the center of the core,[63] which is about the same power density inside a compost pile. https://en.wikipedia.org/wiki/Sun#Core https://en.wikipedia.org/wiki/Sun#Core Another fun fact: there's a decades old design for a gadget that fits at the top of your desk and does nuclear fusion. You could build one yourself, if you are sufficiently dedicated. Unfortunately, no one has ever worked out how to run one of them as a power plant. Ie how to get more useful energy out than you have to put in. https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor
  - deleted 4y ago
    [deleted]
  - PaulHoule 4y ago
    Those Fusors can make a decent neutron source however. Those were invented by Philo Farnsworth, who invented the cathode ray tube for television.