US Department of Energy: Fusion Ignition Achieved • Hacker News Board

Re: US Department of Energy: Fusion Ignition Achieved

#111

Post by tgflynn » Tue, Dec 13, 2022, 5:40 PM UTC

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

I wonder if it might be possible to gain not percentages but orders of magnitude more or less just by making the targets bigger. Is it conceivable that the same basic approach and a comparable amount of input energy could be used to ignite a 100 MJ or even 1 GJ target ? Of course that would present some containment challenges but perhaps not insurmountable ones.

I'm also a bit concerned that this type of research may encounter national security related obstacles. Obviously a pure fusion bomb would be a game changer for nuclear (non-)proliferation.

Re: US Department of Energy: Fusion Ignition Achieved

#112

Post by simiones » Tue, Dec 13, 2022, 5:42 PM UTC

bioemerl wrote: post #20

Here's your most exciting paragraph > LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE). Many advanced science and technology developments are still needed to achieve simple, affordable IFE to power homes and busines…

That's a very apt analogy, as both this and Manhattan are weapons research programs.

I'm not very excited in hearing we'll get even more powerful thermo-nuclear bombs.

Re: US Department of Energy: Fusion Ignition Achieved

#113

Post by spullara » Tue, Dec 13, 2022, 5:42 PM UTC

tgflynn wrote: post #111

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

I wonder if it might be possible to gain not percentages but orders of magnitude more or less just by making the targets bigger. Is it conceivable that the same basic approach and a comparable amount of input energy could be used to ignite a 100 MJ or even 1 GJ target ? Of course that would present some containment challenges but perhaps not insurmountable ones. I'm also a bit concerned that this type of research may…

I mean almost all of the power in a nuclear bomb comes from fusion. The fission part of it is just like the detonator for the real explosion.

Re: US Department of Energy: Fusion Ignition Achieved

#114

Post by dogma1138 » Tue, Dec 13, 2022, 5:42 PM UTC

pdonis wrote: post #98

Calling this "ignition" is a misnomer. The correct term, as given in the article (as opposed to the headline) is exceeding breakeven: more fusion energy output than energy input to the target. "Ignition" means the reaction becomes self-sustaining and does not require any further input of energy to continue.

And it was just that the after the initial laser pulse that triggered ignition there was no need to sustain it to continue to heat up the fuel to induce fusion.

The fact that this indeed was ignition was one of the main reasons why the fusion reaction itself was net positive.

Re: US Department of Energy: Fusion Ignition Achieved

#115

Post by sillysaurusx » Tue, Dec 13, 2022, 5:42 PM UTC

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

This tweet claims that 500MJ of energy was required: https://twitter.com/latzenpratz/status/1602686252486217728

> "had to put 500 megajoules of energy into the lasers to then send 1.8 megajoules to the target - so even though they got 2.5 megajoules out, that's still far less than the energy they originally needed for the lasers," says Tony Roulstone of the University of Cambridge.

But it's good to finally see progress. Very few technologies can transform the world the way a practical fusion reactor could.

Re: US Department of Energy: Fusion Ignition Achieved

#116

Post by [deleted] » Tue, Dec 13, 2022, 5:42 PM UTC

bmmayer1 wrote: post #103

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

This is a stupid question but I don't know anything about fusion: How is it possible for X energy to create X+Y energy in output? Doesn't that violate some fundamental law of physics?

[deleted]

Re: US Department of Energy: Fusion Ignition Achieved

#117

Post by hackernewds » Tue, Dec 13, 2022, 5:42 PM UTC

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

The funding does seem miniscule given we spend 100x more on funding military excursions in the name of energy security

Re: US Department of Energy: Fusion Ignition Achieved

#118

Post by jameshart » Tue, Dec 13, 2022, 5:42 PM UTC

frellus wrote: post #66

I hate to ask this, but have to ... is there any danger of these discoveries being weaponized easily by hostile countries? i.e. does this make unconventional weapons more accessible to countries who otherwise have embargoes on technology and material to make atomic weapons?

A process which has been finally accomplished at one of the most advanced research facilities in the world after decades of effort, and which requires as an energy input almost as much energy as the process produces, is not easily weaponized, no.

Fusion reactions are hard to start. To use one as a weapon would require you to deliver the fusion fuel together with a source of enough energy to start the fusion reaction off. So the most effective way to do so has historically been to trigger them with a nuclear fission reaction from an atomic bomb - which results in a Hydrogen bomb.

In other words, weaponizing fusion generally requires you to already have an extremely powerful weapon.

Weaponizing this laser based inertial confinement fusion approach requires you to deliver a facility the size of the Lawrence Livermore lab plus the electricity generating capacity of a significant part of the west coast of America onto your target.

Re: US Department of Energy: Fusion Ignition Achieved

#119

Post by jperras » Tue, Dec 13, 2022, 5:42 PM UTC

bmmayer1 wrote: post #103

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

This is a stupid question but I don't know anything about fusion: How is it possible for X energy to create X+Y energy in output? Doesn't that violate some fundamental law of physics?

Energy is released when two atomic nuclei combine to form a larger atomic nuclei.

There's a threshold of energy required to attain this fusion reaction (otherwise there would be no light nuclei in the universe), and once the nuclei combine there's energy that is released, similar to how some chemical reactions can be exothermic in nature.

Re: US Department of Energy: Fusion Ignition Achieved

#120

Post by tekla » Tue, Dec 13, 2022, 5:43 PM UTC

bmmayer1 wrote: post #103

jkelleyrtp wrote: post #33

> LLNL’s experiment surpassed the fusion threshold by delivering 2.05 megajoules (MJ) of energy to the target, resulting in 3.15 MJ of fusion energy output, demonstrating for the first time a most fundamental science basis for inertial fusion energy (IFE) Yesterday, everyone was complaining about the 2.2:2.0 ratio, but now we're working with 3.15:2.05. With modern lasers, that'd be a total Q of 0.375 assuming 100% ef…

This is a stupid question but I don't know anything about fusion: How is it possible for X energy to create X+Y energy in output? Doesn't that violate some fundamental law of physics?

You have a piece of wood. You ignite it with a match. This causes a self sustaining reaction in the form of fire that releases far more energy than the match could ever create.

This is effectively what is happening with any energy generator.