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US Department of Energy: Fusion Ignition Achieved

energy.gov

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Re: US Department of Energy: Fusion Ignition Achieved

#471

Post by short_sells_poo »

jmartrican wrote: post #443
eklitzke wrote: post #262

Earlier quoted context omitted.

Tangentially related, but I think this is an interesting fact, all the atoms in our universe/galaxy/solar system with a mass up to that of iron are formed in the core of stars in stellar fusion. Hydrogen fuses into helium, and as a star nears the end of its lifetime you get heavier elements like lithium, carbon, and so on. Under normal stellar fusion no elements heavier than iron will be produced, and iron is only el…

So that means that for life to form, we probably need a star to die so that the heavier atoms used in complicated life forming chemical reactions (correct me if i am wrong here as what I'm about to say depends on it), hence it could be the case that if the universe is 13.5 billion years old, then we humans are appearing in the universe at the earliest possible time. 13.5 billion years seems like the time required to…

I'm just a layman but I believe by the time our sun has formed, we've gone through multiple star cycles. The early stars were very pure - made basically purely of hydrogen (maybe some helium?). They were huge, burned very bright and died comparatively quickly. Each time stars died, more heavy elements (and heavier elements than before) were produced. Over time the heavy element content (called metallicity) has increased in all stars. I believe there are also theories of white dwarf mergers undergoing runaway fusion and a lot of heavy elements being generated during the explosion.

You raise an interesting question though: what is the earlier point of time where the heavy elements were abundant enough for life (as we know it) to form? Just because we started existing at +13.5 billion years, it doesn't mean carbon based life couldn't have formed much earlier.

Re: US Department of Energy: Fusion Ignition Achieved

#472

Post by wahern »

petilon wrote: post #415
whimsicalism wrote: post #395

Earlier quoted context omitted.

Energy is conserved in the universe so there is never any net energy gain. See how pedantic and not helpful that is?

In nuclear fusion, mass is converted into energy according to the famous equation E = mc^2, where E is energy, m is mass, and c is the speed of light.

Mass is energy. Add energy (in any form, such as heat) to a system and you increase its mass. Thus, in the NIF reaction, the mass lost from the pellet is mass imparted on the surrounding environment. Immediately after the fusion reaction, before the energy can dissipate further as heat, etc, the reaction chamber system has the same mass as before the ignition.

There are some nuances regarding the distinction between rest mass vs relativistic mass, but they're not really relevant in this context.

I think what trips people up here is confusing mass with matter. Matter is also subject to mass-energy equivalence, of course, but AFAIU in most common types of nuclear reactions little if any matter, per se, is transformed.

Re: US Department of Energy: Fusion Ignition Achieved

#473

Post by TeeMassive »

davedx wrote: post #393
makestuff wrote: post #353

Earlier quoted context omitted.

> It's nice to see this milestone recognized, even if the funding it still rather small. Just wait until the DoD figures out they can use this for some military application and it will get 100x funding overnight.

We've had thermonuclear weapons (h-bombs) for a long time already. Harnessing the energy in a controlled and sustainable fashion is what's hard.

H-bombs use the hydrogen to produce more neutrons which boosts the fission process. It still is a fission bomb.

Re: US Department of Energy: Fusion Ignition Achieved

#474

Post by saboot »

davrosthedalek wrote: post #464
saboot wrote: post #413

Earlier quoted context omitted.

It's an explicit goal of the NIF to better understand the physics of fusion for weapons research. Not the main one but it's pretty important!

My point was: NIF would be funded via DOE whether or not it's relevant for weapon research. Sorry for not have been clearer.

If it was already decided to be funded, yes it would have been under DoE. Though I believe the weapons aspect had a very major contribution in deciding for it to be funded at all. It was proposed shortly after the nuclear testing ban and has been a big part in fulfilling that area.

I'm not trying to correct you, but adding context for the weapons aspect.

Re: US Department of Energy: Fusion Ignition Achieved

#475

Post by snowwrestler »

petilon wrote: post #349
mustacheemperor wrote: post #2

I don't know about everyone else, but I'm taking this particular moment just to swell with pride and excitement for this achievement by science and forget about the details of how much more needs to be done to create the first power plant. I'm remembering when I first learned about fusion energy development, how distant and unfeasible it seemed, and regardless of how long the road ahead still is it's incredible how f…

When you consider that they laser they used consumed 300 megajoules from the wall plug, in order to send 1.8 megajoules to the target, the fact that they got 2.5 megajoules out looks puny in comparison. Even newer lasers only have 20% wall plug efficiency according to the press conference. So the important point here is, there was no net energy gain. They spent 300 megajoules to get 2.5 out. The scientists only talk…

The NIF is not intended to be a power plant, and inertial containment in general is probably not a great design for producing power.

This is scientific breakthrough. The best point of comparison is probably a fusion bomb, which requires an initial fission detonation to create enough pressure and free neutrons to force a net-positive fusion reaction. But at the NIF they do it using only lasers… incredible.

Re: US Department of Energy: Fusion Ignition Achieved

#476

Post by lostmsu »

adamvalve wrote: post #48
sergiotapia wrote: post #34

The future just got a whole lot brighter for my children. This is going to save our planet, not funky wind farms.

No need to pit them against each other. This achievement wasn't certain. Multiple paths towards a more sustainable future is better for everyone.

> Multiple paths towards a more sustainable future is better for everyone.

That is debatable.

Re: US Department of Energy: Fusion Ignition Achieved

#477

Post by Firmwarrior »

eitland wrote: post #392
Firmwarrior wrote: post #293

Earlier quoted context omitted.

Let's take a step back and remember something: If Russia and the USA had a "war" it would consist of reducing each other to the Stone Age in a couple of hours, then struggling not to starve to death

Why do you think a country that isn't capable of properly maintaining tanks is capable of maintaining nukes? I mean, ICBMs are literally rocket science with nuclear physics on top of them. How can a country that cannot even prevent theft of electronics from their "doomsday plane" in front of the 9th of May parade keep a fleet of ICBMs operative? In a normal year Russia has a total military budget that is smaller than…

Do you remember when there was a tiny blip in production for COVID, and suddenly the shelves were empty? What do you think is going to happen if 100 nukes go off and wipe out strategic chunks of the USA?

Re: US Department of Energy: Fusion Ignition Achieved

#478

Post by short_sells_poo »

MayeulC wrote: post #460
ajross wrote: post #300

Earlier quoted context omitted.

Actually current modeling has supernovae as being only a small contributor to the measured abundance of heavy nucleii. These guys tend to come from a more exotic source still: material thrown off as a neutron star is tidally disrupted during a merger event with another neutron star or black hole . The wikipedia page is pretty good, as always: https://en.wikipedia.org/wiki/Nucleosynthesis Almost everything with mass o…

After all, is there anything better to create new elements than a hot, dense neutron soup?

I'm always fascinated by the sheer and unfathomable amounts of energy that is thrown around in these events. Just thinking about the fact that a single spoonful of neutron star matter contains more mass than Mount Everest fills me with wonder about the world we live in.

Re: US Department of Energy: Fusion Ignition Achieved

#479

Post by metal_am »

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…

This particular research is literally built off of weapons research (National Ignition Facility).

Re: US Department of Energy: Fusion Ignition Achieved

#480

Post by gretch »

steam_raven wrote: post #451
stock_toaster wrote: post #338

Earlier quoted context omitted.

“The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of star stuff”. – Carl Sagan

We have calcium in our bones, iron in our veins, carbon in our souls, and nitrogen in our brains. 93 percent stardust, with souls made of flames, we are all just stars that have people names" Nikita Gill

I understand this is a poem that is focused on artistic expression and not scientific accuracy, but I find the line about “carbon in our souls” to be out of place. I guess the rest of the poem is incidentally correct (when not abstract)
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