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Science

'Burning' Hydrogen Plasma In the World's Largest Laser Sets Fusion Records (livescience.com) 87

The secret behind a record-breaking nuclear fusion experiment that spit out 10 quadrillion watts of power in a split second has been revealed: a "self-heating" -- or "burning" -- plasma of neutron-heavy hydrogen inside the fuel capsule used in the experiment, according to researchers. Live Science reports: Last year, scientists at the Lawrence Livermore National Laboratory in Northern California announced the record release of 1.3 megajoules of energy for 100 trillionths of a second at the National Ignition Facility (NIF), Live Science reported at the time. In two new research papers, NIF scientists show the achievement was due to the precision engineering of the tiny cavity and fuel capsule at the heart of the world's most powerful laser system, where the fusion took place.

Although the fuel capsule was only about a millimeter (0.04 inch) across, and the fusion reaction lasted only the briefest sliver of time, its output was equal to about 10% of all the energy from sunlight that hits Earth every instant, the researchers reported. The researchers said the reaction blasted out that much energy because the process of fusion itself heated the remaining fuel into a plasma hot enough to enable further fusion reactions. "A burning plasma is when heating from the fusion reactions becomes the dominant source of heating in the plasma, more than required to initiate or jump-start the fusion," Annie Kritcher, a physicist at the Lawrence Livermore National Laboratory (LLNL), told Live Science in an email. Kritcher is the lead author of a study published Jan. 26 in Nature Physics describing how the NIF was optimized to achieve the burning plasma, and the co-author of another study published in Nature the same day that details the first burning plasma experiments at NIF in 2020 and early 2021.

The two new studies describe burning plasma experiments conducted in the months before the 10 quadrillion watt reaction; those earlier experiments culminated in the production of 170 kilojoules of energy from a pellet of just 200 micrograms (0.000007 ounces) of hydrogen fuel -- around three times the energy output of any earlier experiments. It was achieved by carefully shaping both the fuel capsule -- a tiny spherical shell of polycarbonate diamond that enclosed the pellet -- and the cavity that contained it -- a small cylinder of depleted (not very radioactive) uranium lined with gold, known as a hohlraum. The new designs allowed the NIF lasers that heated the pellet to operate more efficiently within the hohlraum, and the hot shell of the capsule to rapidly expand outward while the fuel pellet "imploded" -- with the result that the fuel fused at such a high temperature that it heated other parts of the pellet into a plasma.

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'Burning' Hydrogen Plasma In the World's Largest Laser Sets Fusion Records

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  • Call me a cynic (Score:5, Insightful)

    by Viol8 ( 599362 ) on Thursday January 27, 2022 @05:09AM (#62211007) Homepage

    But a method of power generation that requires constantly dropping capsules in a hard vacuum to be hit by high powered lasers to create heat which is somehow collected and use to generate power doesn't sound the most practical or reliable way to do it. If Heath Robinson (or Rube Goldberg for americans) had been asked to design a fusion power system he'd have probably come up with something like this.

    • Since it generates enough power to trigger a self-sustaining reaction, it might be usable as a way to initiate the reaction in a conventional fusion reactor, as clearly we're now in the right temperature range.

      • Since it generates enough power to trigger a self-sustaining reaction

        It generated 1.3 MJ. That is roughly the amount of energy needed to warm up a pot of tea.

        • Since it generates enough power to trigger a self-sustaining reaction

          It generated 1.3 MJ. That is roughly the amount of energy needed to warm up a pot of tea.

          In 100 trillionths of a second. My kettle takes several minutes.

          • In 100 trillionths of a second. My kettle takes several minutes.

            The difference is that your kettle can heat more tea a few minutes after the first.

            NIF needs hours or days of setup for the next pellet.

          • The important thing in a power plant is not how hast the nanoexplosions are, it is how fast you can explode them is series. How many "pots of warm tea" per second. The NIF has a repetition rate of a day. To get a thermal output of a major powerplant unit of, say 1.7 GW thermal with explosions like this, you need 10,000 of these a second.

            But the more important metric, the standard of the field, that LLNL does not mention in this paper, nor provide the information to calcualte, is "break even" (Q) - getting o

        • I would love to know what you consider "a pot of tea".
          In order to heat 1 liter of water from 22C to 100C it requires about 326500 joules.

        • Since it generates enough power to trigger a self-sustaining reaction

          It generated 1.3 MJ. That is roughly the amount of energy needed to warm up a pot of tea.

          The experiment described in the paper generated 170 KJ, not 1.3 MJ. That claim, which I presume is true, was tacked on to the end but not addressed in any way in the paper.

          Yeah, warm pot of tea. One liter is good full pot, and 170 KJ would heat it 40 C, so assuming your tap water is 20 C, you get lukewarm-ish 60 C tea. i like my tea water to boil at 100 C.

    • by gtall ( 79522 ) on Thursday January 27, 2022 @05:20AM (#62211023)

      Ya, they should forget all that silly research on how to make fusion, and just produce a fully functioning fusion reactor. You seem to know a lot about the area, maybe you could tell them how to do it. I'm sure they'd listen to you.

      • by Viol8 ( 599362 )

        There are certain practicalities of engineering that are universal. Eg - short of putting enough pellets stored at the top of the chamber to last decades there's got to be some kind of airlock with a conveyer system to get them in there and i've yet to see anyone build anything like that. Though if you know of one do let us know.

        • Comment removed based on user account deletion
          • by Viol8 ( 599362 )

            Yeah, lets no worry about minor practicalities like how the fuck to we provide fuel to it , lets just do the fun stuff and wing the rest! Whatever.

            • The mission of the NIF is to do research for thermonuclear weapons, not to build fusion reactors.

              • by Viol8 ( 599362 )

                What do they need to research? Compress H2 enough - bang. Solved in the 60s. Perhaps they need to find something else to waste tax money on.

    • Crap, I hadn't realised they were basically doing a miniature H-bomb.

      The radioactivity from this scaled up will be horrible. It'll never be useful for power generation.

      • by evanh ( 627108 )

        Which suggests the primary research goal is to make miniature nuke weapons.

        • by algaeman ( 600564 ) on Thursday January 27, 2022 @05:41AM (#62211053)
          This^. NIF is not intended for power generation research. It is used to model fusion reactions for the development of fusion weapons.
          • by storkus ( 179708 ) on Thursday January 27, 2022 @07:13AM (#62211161)

            This^. NIF is not intended for power generation research. It is used to model fusion reactions for the SHRINKING of fusion weapons.

            FTFY. Suit Case Nukes, the real kind, not a giant back pack.

            This is also in the summary and article and Wiki and...well, for non-USA people, the Dept of Energy has 2 sides, the civilian one with solar panels & the like, and the Military Industrial Complex side that to this day is in charge of nuclear weapon development. LLNL, Oak Ridge, Los Alamos, etc all fall under this umbrella.

            • the Dept of Energy has 2 sides, the civilian one with solar panels & the like, and the Military Industrial Complex side that to this day is in charge of nuclear weapon development. LLNL, Oak Ridge, Los Alamos, etc all fall under this umbrella.

              It is helpful to note that of the "two sides" the nuclear weapons side is the overwhelmingly dominant one. Using the current DOE budget [energy.gov] 74% of the spending is on "national security" (i.e. nuclear weapons). And I believe this research, though applicable to nuclear weapons design, is actually being counted as part of their scientific research (not national security) budget.

              The department could be described more accurately as "the department of nuclear weapons". This is partly, BTW, why the very high U.S. mili

      • wrapped in DEPLETED uranium. That is barely radioactive uranium. Details matter you know?
        • "Barely radioactive" is stretching facts past the breaking point. Depleted uranium is somewhat more than half as radioactive as natural uranium, due to the remove of U-234 (yes U-234, not U-235 though this is also removed) so moderately reduced radioactivity, not anything like a reduction to "barely".

          In a hydrogen bomb depleted uranium would behave exactly like natural uranium, which was used in the hydrogen bombs built in the 1950s, providing radiation confinement (as in this NIF target) and fissioning fro

        • You seem not to know what "depleted" actually means. Hint: it has absolutely nothing to do with radioactivity. (Yeah, some nitpickers will jump on it and want to point out different half lives, go for it).

      • Yes, as soon as I saw it was a diamond shell with an igniter of Uranium inside, I thought crap, they made a bomb.
    • Yes, but if you want to understand nuclear fusion weapons better and have an agreement not to do nuclear tests then this is helpful. There's a good reason why laser fusion is often more funded by the US government and more likely to have its details classified than magnetic confinement fusion.
    • by necro81 ( 917438 )

      But a method of power generation that requires constantly dropping capsules in a hard vacuum to be hit by high powered lasers to create heat which is somehow collected and use to generate power doesn't sound the most practical or reliable way to do it.

      Furthermore, with a yield of 1.35 MJ, you would need to do several hundred to several thousand such shots per second in order to create utility-scale power.

      Reiterating the common complaint people have been making about NIF for years: it is not at all a mo

    • Not necessarily a cynic, just uninformed. That isn't how it is intended to work. The little pellet is like a trigger. The whole point this is starting to self-sustaining fusion reaction for all you need is more fuel, not more triggers. Like starting a fire, just keep feeding it wood once it gets started.

      • Not necessarily a cynic, just uninformed. That isn't how it is intended to work. The little pellet is like a trigger. The whole point this is starting to self-sustaining fusion reaction for all you need is more fuel, not more triggers. Like starting a fire, just keep feeding it wood once it gets started.

        Only in this case, the "wood" is a highly energetic gas made of mutually-repulsive bits of wood which you're trying to squeeze together to sustain the fire like trying to squeeze a blob of sentient jelly with rubber bands. It's much more complicated than "give it more fuel."

      • In order to sustain fusion you need confinement.

        The sun does it with gravity.

        AFAICT NIF is using inertial confinement, which works for ignition but cannot possibly work for a sustained reaction.

    • Call my a cynic, but a method of power generation that requires two and a half megajoules of laser energy to produce 1.3 megajoules of fusion energy is a tad on the inefficient side.

    • But a method of power generation that requires constantly dropping capsules in a hard vacuum to be hit by high powered lasers to create heat which is somehow collected and use to generate power doesn't sound the most practical or reliable way to do it. If Heath Robinson (or Rube Goldberg for americans) had been asked to design a fusion power system he'd have probably come up with something like this.

      You seem to have missed the point of the experiment, mainly that it's an experiment. They're not attempting to build a functioning power plant out of this. We have to understand the principles of fusion better first, then comes the "OK, now how do we make a practical reactor out of this" part. You're essentially saying to a caveman who just discovered fire that he should immediately skip to building a modern internal combustion engine for an F1 car, all without ever understanding the principles of combus

    • Comment removed based on user account deletion
  • is just the German translation of the word 'cavity', literaly meaning "hollow space".
  • US spending on fusion research is down to ~$230 million per year. To put that in context, Elon Musk could fund this level of research for 1000 years before he ran out of money, and Bezos is currently spending $1.2 billion on a new mega yacht that has a baby super yacht to follow it around carrying his helicopter.

    The truth of the matter is that nobody in power actually wants to build a fusion reactor anytime soon. The research done so far, overwhelmingly suggest we can get there, but the funding still doesn'

    • Naah, they probably love the idea of fusion-a-my-jig power but believe govt should step aside & let the markets develop it.
    • The truth of the matter is that nobody in power actually wants to build a fusion reactor anytime soon. The research done so far, overwhelmingly suggest we can get there, but the funding still doesn't even get increased.

      No problem. The Ocasio-Cortez administration will just buy its fusion reactors from China.

    • The meme: https://www.genolve.com/design... [genolve.com]
  • Watts are joules per second. So you do not put out quadrillions of watts in a fraction of a second.

    I think the math is right but the only flaw is "fraction of a second". You put out 1.3 million joules in 100 trillionths of a second (a fraction of a second), which amounts to quadrillions of watts, if it were to last a second, which it didn't.

    With a lame phone calculator and no pen and paper to deal with large exponents, I assume you get quadrillions dividing millions by tenth of a billionth.

    Dang, I wonder

    • Now if we could release quadrillion watts in zero seconds - infinite power.
      • A quadrillion sounds pretty hard.
        What if instead we release just 42 watts in zero seconds, and still generate infinite power...
        • I think you just won the internet.
        • by Malc ( 1751 )

          A quadrillion sounds pretty hard.
          What if instead we release just 42 watts in zero seconds, and still generate infinite power...

          Would that be 42 watts in an instant?

          The article said:

          its output was equal to about 10% of all the energy from sunlight that hits Earth every instant

          How long is an instant?

    • by ceoyoyo ( 59147 )

      which amounts to quadrillions of watts, if it were to last a second, which it didn't.

      You made essentially the same mistake. One million joules in 100 trillionths of a second is 1000 quadrillion watts. If you maintained that power output for one second it would be ten billion times as many joules, same number of watts.

    • With a lame phone calculator and no pen and paper to deal with large exponents, I assume you get quadrillions dividing millions by tenth of a billionth.

      The first apps to go on my phone(s) are signal generators, scientific calculators. oscilloscopes, network tools and sensor viewers. Turn in your nerd card.

  • The game is to make meaningless, but impressive sounding announcements so that scientists can get more funding and keep their jobs. Until there is energy coming to my home from fusion I won't believe anything.

  • This means it's still YEARS away from me becoming iron man. :( (Or that I could create the technology and have a Monopoly on it) ;)
  • How many nuclear batteries you would get in GUARDED BUILDING CONNECTED TO POWER GRID with the whopping price of this endeavor?
  • It seems to me that any government project takes ten times longer to produce any results than it should. Note: military projects are not government projects.
    Case in point: NASA took almost a decade to get to the moon. They took their sweet time building the shuttle. They're taking decades to come up with a lunar-capable launch vehicle. Meanwhile, SpaceX is making them look flat out lazy. Point being what would happen if someone like Elon Musk took on fusion power?

    • Point being what would happen if someone like Elon Musk took on fusion power?
      Nothing.

      Some things are engineering. Rockets for example.

      Some things are hard science, e.g. Fusion.

      Does not mean that "Rocket Science" does not involve Science :P

  • For the past 50 years, fusion workers have been breaking records. The good news is that the successfulness of fusion is increasing all the time. The bad news is that despite always increasing, it is increasing to an asymptote that does not reach practical ability to generate power at scale.

  • For fun, I did the math. The US used about 3.6e9 kWh of electricity last year. That's about 13e18 joules.

    At 1.3e6 J/pellet, we need to fuse 10 trillion pellets a year. That's 300,000/second. We have around, oh I don't know, 300 fusion power plants, that's one pellet every millisecond per plant.

    I guess that's not impossible. It's in the realm of you could imagine building a system in that range. You'd likely want to make much bigger pellets to reduce the firing rate, things like that.

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