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Science

Laser Fusion Experiment Unleashes an Energetic Burst of Optimism (nytimes.com) 187

An anonymous reader quotes a report from The New York Times: Scientists have come tantalizingly close to reproducing the power of the sun -- albeit only in a speck of hydrogen for a fraction of a second. Researchers at Lawrence Livermore National Laboratory reported on Tuesday that by using 192 gigantic lasers to annihilate a pellet of hydrogen, they were able to ignite a burst of more than 10 quadrillion watts of fusion power -- energy released when hydrogen atoms are fused into helium, the same process that occurs within stars. Indeed, Mark Herrmann, Livermore's deputy program director for fundamental weapons physics, compared the fusion reaction to the 170 quadrillion watts of sunshine that bathe Earth's surface. "This about 10 percent of that," Dr. Herrmann said. And all of the fusion energy emanated from a hot spot about as wide as a human hair, he said.

But the burst -- essentially a miniature hydrogen bomb -- lasted only 100-trillionths of a second. Still, that spurred a burst of optimism for fusion scientists who have long hoped that fusion could someday provide a boundless, clean energy source for humanity. The success also signified a moment of redemption for Livermore's football-stadium-size laser apparatus, which is named the National Ignition Facility, or N.I.F. Despite an investment of billions of dollars -- construction started in 1997 and operations began in 2009 -- the apparatus initially generated hardly any fusion at all. In 2014, Livermore scientists finally reported success, but the energy produced then was minuscule -- the equivalent of what a 60-watt light bulb consumes in five minutes. On Aug. 8, the burst of energy was much greater -- 70 percent as much as the energy of laser light hitting the hydrogen target. That is still a losing proposition as an energy source, consuming more power than it produces. But scientists are confident that further jumps in energy output were possible with fine-tuning of the experiment.

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Laser Fusion Experiment Unleashes an Energetic Burst of Optimism

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  • And use it to feed the lasers to create the next one and so forth?

    • You can definitely extract the power from it. We've done that plenty of times, with fusion bombs.
      The trick is doing it in a controlled way that, as you say, let's you feed power back into the loop with extra left to power the city.

      • I would not call that "extracting power". I would call that "depositing an enormous, stunningly destructive payload".

        • If you did this in a giant ball of mass, repeatedly, and heat it to a bright glow, you could then use photovoltaics to harness the energy without destroying anything, assuming the ball of mass was sufficiently large enough, and far enough away to not irradiate things too close by...
    • Thats kind of the plan.

      The big hurdle (well there are many, but at a more macro level) is for fusion power to be useful it needs to generate more power than is fed into it. Once it can do that, then you just loop it around and scoop off the excess. Although one must presume the next big goal would be figuring out how to scale it.

      70% is an awesome achievement. We where orders of magnitude away from the goal not too long ago. Now they just need to squeeze that extra 30% and someones gonna get themselves a nob

      • Side question, are nuclear bombs net-positive? In reading about the first 2 dropped on Japan, they could not have been, after factoring in all the efforts that went into building and delivering them. (Building and running the centrifuges, constructing Los Alamos...)
  • This sounds like the Onion
  • I have had the fortune to tour NIF a couple of times. It's a very impressive and interesting facility.

    Lots of people with "Q" clearances work there!

    • Re: (Score:2, Interesting)

      by sg_oneill ( 159032 )

      Just so we're clear, because its not always clear.

      "Q" clearances are meaningless outside the Dept of Energy. Theres an entire subculture of astonishingly gullible idiots on the net that seem to think someone with a "Q" clearance would know about anything secret that isn't hydrogen bombs.

      For instance: There is no such thing as a "CIA agent" with a "Q" clearance. Nor is there a Pentagon clearance called "Q" or an FBI, Homeland security or so on.

      Its just the guys who know the sensitive stuff about how to build

    • I figured they all worked at DARPA. Still waiting on that Lotus turned Submarine to arrive.
  • Numbers don't add up (Score:5, Informative)

    by Solandri ( 704621 ) on Wednesday August 18, 2021 @12:15AM (#61703643)

    they were able to ignite a burst of more than 10 quadrillion watts of fusion power [...]
    But the burst -- essentially a miniature hydrogen bomb -- lasted only 100-trillionths of a second [...]

    10 quadrillion watts * (1/100 trillion) sec = 100 joules

    In 2014, Livermore scientists finally reported success, but the energy produced then was minuscule -- the equivalent of what a 60-watt light bulb consumes in five minutes

    60 Watts * 5 minutes = 18000 joules

    It's Lawrence Livermore, so I'm more inclined to believe this is an error by the NYTimes reporter, rather than an error by LLNL. Does anyone know what the real numbers are, so I know whether or not to be excited?

    • by TechyImmigrant ( 175943 ) on Wednesday August 18, 2021 @12:27AM (#61703653) Homepage Journal

      Journalists at journalist school all attend a mandatory course called "How to always get the units messed up". That is why they are incapable of presenting any technical information coherently.

    • Probably they mean the laser pulse lasted for 1/100 trillionth of a second, but the fusion then released 10 quadrillion watts in the (unspecified) time following, which was still only 70% of the power that went into the laser pulse.

    • by fgrieu ( 596228 )
      Never trust the general press when dealing with trillions or larger. The energy released is 1 300 000 J according to https://www.llnl.gov/news/nati... [llnl.gov]
      • by colfer ( 619105 )

        Billion used to mean trillion in the U.K.! The period around the official switchover in 1974 was a confusing one for journalists there. Billion is a more common number, and they called it "thousand million." As for trillion, maybe that's where Carl Sagan first heard "million million."

    • by quenda ( 644621 )

      100-trillionths of a second [...]
      10 quadrillion watts * (1/100 trillion) sec = 100 joules

      100 / trillion vs 1/(100 trillion) ? You seem to be off by four orders of magnitude. I make it 1000kj.

      It's Lawrence Livermore, so I'm more inclined to believe this is an error by the NYTimes reporter

      Or maybe not?

      • by quenda ( 644621 )

        You seem to be off by four orders of magnitude. I make it 1000kj.

        Or, for our American readers, 238 calories.

        This is a lesson on why to use standard notation.
        Clearer to say "0.1 nanosecond" and "10 Terawatt".
        Even better, use scientific notation.

        • Or, for our American readers, 238 calories.

          Calories are a metric unit: The energy used to heat a gram of water one degree C.

          The "American" unit for thermal energy is the BTU: The energy used to heat a pound of water one degree F.

          The "American" unit for mechanical energy analogous to the Joule is the foot-pound.

          • Re: (Score:3, Informative)

            by AmiMoJo ( 196126 )

            Ironically the "American" unit is British Thermal Units (BTUs).

            Similarly they use English measures, even though in England they use the slightly different Imperial measures.

        • by necro81 ( 917438 )

          Or, for our American readers, 238 calories.

          Clarification: that's food calories, as one would find on a U.S. nutritional label - the energy to heat one kilogram of water by one degC. In the rest of the world, food calories are properly called kilocalories.

      • 10 quadrillion watts * (100 trillionth) sec = 10**13 * 10**-7 = 10**6 = 1M joules

        • It's kinda early morning here, but isn't a 100-trillionth (1 / 100 trillion) 10**-14? If it's supposed to be 100 trillionths (100 / trillion), isn't that still 10**-10? 10**-7 would be 100 / million.
    • by technology_dude ( 1676610 ) on Wednesday August 18, 2021 @06:00AM (#61704087)
      A better article

      https://www.bbc.com/news/scien... [bbc.com]
    • 10 quadrillion watts * (1/100 trillion) sec = 100 joules ... 60 Watts * 5 minutes = 18000 joules

      Close enough for astrophysics.

      The point is that an enormous amount of power produced in a tiny instant of time does not amount to much energy, and energy is what you need to get stuff done. Producing enormous instantaneous power output from nuclear fusion was done long ago, in thermonuclear bombs. Making the power continuous and controllable is the tricky bit.

    • by JustinOpinion ( 1246824 ) on Wednesday August 18, 2021 @09:50AM (#61704641)
      The NIF press release [llnl.gov] is a bit better.

      Fusion yield was 1.3 MJ per pulse/capsule. Laser energy delivered to the fusion capsule was 1.9 MJ, so the efficiency is 68% by that metric. However this omits the laser energy that didn't get correctly focused/absorbed by the capsule, as well as the energy lost in the lasers themselves (which are probably ~1% efficient). The press release doesn't list a gain factor [wikipedia.org], but based on other results NIF has reported, I believe this new result is roughly Q ~ 0.007. This is a huge achievement for NIF (who were sitting at Q ~ 0.00008 in 2013 and Q ~ 0.0003 in 2018). However Q = 1 is what's necessary to reach "scientific breakeven" where the fusion energy output equals the energy input for heating the plasma. Obviously a viable power plant needs to be Q > 1 to account for other losses (like the inefficiency of capture/conversion into electricity). Q > 5 ("ignition") is considered necessary to achieve a self-propagating fusion reaction.

      By way of comparison, the current record for magnetic confinement fusion is Q = 0.67 achieved by JET [wikipedia.org] in 1997.

      Should we be excited? This is great progress, and every new experiment increases our understanding of the complicated physics of fusion plasmas. From a scientific and engineering perspective, this is amazing. However, if you're most interested in eventual fusion power, then magnetic confinement (tokamak [wikipedia.org] designs) are well ahead, and ITER [wikipedia.org] is much more likely than NIF to provide a pathway to fusion power plants.
  • We can skip a few steps and go straight to inferno!

  • From my understanding, the major hurdle with fusion power generation is that it takes more energy to sustain the reaction than you get out of it. So relative to the amount of energy consumed by the lasers to initiate the reaction, did they at least get more energy out in the end?

      • Short, simple, to the point... I like it! Thanks!

        • 70% of what they put in came back out. This is actually a phenomenal achievement, and several times better than what they expected. So worth getting excited about, but still far far far from a practical power plant.

    • by HiThere ( 15173 )

      It's considerably worse than that. This approach to laser fusion is of only theoretic and technical interest. Those huge lasers are enormous, enormously expensive, enormously fragile, and require huge amounts of on-going maintenance. (Well, I'm assuming it's the same approach it was the last time I looked into it.) They also last for a limited number of cycles, because that sudden surges of power put them under lots of stress.

      That said, the theoretic and technical reasons *may* justify it. But I'd be r

  • by Pravetz-82 ( 1259458 ) on Wednesday August 18, 2021 @01:31AM (#61703747)
    This is fusion WEAPON research.
    How exactly fusion power is supposed to be generated and extracted in this kind of setup ?!? How do you make it a continuous or at least repeatable, so it generates heat ? Even if you can cycle those powerful lasers fast enough (which I seriously doubt) how are the pellets going to be loaded? They will need moving parts inside the burn chamber and insane precision...
    This is fusion weapon research masked as fusion power research.
    • Don’t be so cynical. I’m confident this research has gotten us to the point where we’re only 10-15 years away from practical fusion energy!

    • How do you make [laser fusion] a continuous or at least repeatable, so it generates heat?

      How do you make the combustion in an automobile engine continuous so it can turn the shaft and smoothly push the car? You DON'T HAVE TO! ... how are the pellets going to be loaded?

      How are machine-gun bullets "loaded" into a target?

      They will need moving parts inside the burn chamber ...

      Just like the machine gun target needs moving parts (other than the bullets)?

      They will need ... insane precision

      LASER light systems are

    • This is fusion weapon research masked as fusion power research.

      I don't know how you justify that assessment. Is anybody is interested in making better thermonuclear bombs, when current technology could wipe us all out many times over?

      A basic problem with peaceful applications of nuclear fusion is that the conditions to produce fusion are extreme, and often can only be produced in explosive events. That does not imply you are making bombs.

      Years ago, I researched magnetic field theory, and came across something called the "exploding coil method". Iron is often used to co

    • There's another school of thought which suggests that if this could be perfected, there'd be a lot less need for weapons. The thinking being that if we can stop squabbling over oil or whatever else, then we won't need the weapons we threaten each other with every day.

      There may well be some weapons research going on here. But one wonders just how much more powerful we need a weapon to be than the fission bombs we already have. More efficient and cheaper to own perhaps, but otherwise, not sure what else.

    • Like all the US federally funded nuclear research, it is dual use. Private enterprise is coming to the rescue whose aims are strictly commercial power generation.

      The NIF did reach an important milestone - they achieved ignition proving that inertial confinement (heat & pressure) can produce almost as much output energy as input energy using something other than a fission explosion. It basically proves that it is possible. We also have experimental evidence to back up the mathematical model needed to
  • The way they're doing it is useless for energy production, but very useful for weapons research, and everybody knows it. They're not even trying to hide it. At this point, the only thing nobody gets, is why they're acting as if it's not.

  • What they did was they produced roughly 0.000000028 kilowatt-hours of energy.

    If that doesn't sound like much, it's because it isn't.

    So can somebody explain to me what difference a supposedly really high power output makes when the total energy produced is still negligible? What does this sort of thing prove, exacty?

  • This is a dupe. I read the same story in 1964. Also, every few years thereafter.

  • Reality Check (Score:4, Informative)

    by sudonim2 ( 2073156 ) on Wednesday August 18, 2021 @10:01AM (#61704669)
    This took place at the National Ignition Facility at Lawrence Livermore. Herman is the "deputy program director for fundamental weapons physics" because that's what the NIF researches: nuclear weapons. This facility exists to study and better understand high energy plasma physics and inertial confinement fusion to better understand the physics of nuclear bombs to make them cheaper, "cleaner", safer, smaller, and more powerful. At no point in its history has the NIF studied energy generation. Its experiments have nothing to do with fusion based power generation. The technology they use almost certainly will never be used to generate power. But it's the only fusion research facility that's ever crossed the break-even point, so a certain type of nerd, and thus a certain type of reporter, obsess over it.

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