The military said something like: "Telephone routing is point to point and inflexible, if the enemy cuts out 1-2 lines of communication, an entire section is completely cut off. We need something better." That something better turned out to be packed switching where you just throw stuff along a network and the network ensures that the packet reaches the destination, but you could theoretically have two packets going from Bucharest to Johannesburg, one through India and the second one through Canada.
It's much easier than the same operation for physical infrastructure.
If you look at the "shot history" of NIF -- the vast majority of their facility's energy is spent on actual DOD weapons research, not fusion research that would be incidentally beneficial to the DOD:
The physics are known to work and have been demonstrated decades ago in a different engineering context (i.e. weapons).
A bomb? Already done.
A fusion reactor? We’re still light years away from anything of the sort. This is only one tiny tiny step there, and we’ve got miles to go.
For sure, you can’t even consider the possibility of a fusion power plant without the core reaction producing power. That they figured out how to do the energy equivalent of getting the coal to actually light (finally!) in this context, is indeed useful.
But it is a tiny, tiny step towards an actual working fusion power plant.
And it does nothing to fix the economic issues here in competition with all the other energy sources, which matters.
Igniting that bit of ‘coal’ took near 100x the energy we got out of it. It was essentially putting it in a giant blowtorch, and then getting excited when it finally got lit and burned. That we previously only got half smoldering was indeed a problem! And that it finally lit is indeed cool.
it also took an extreme amount of thought, precision, investment, etc. to do it once.
Meanwhile, solar plants in the area were churning out billions of kwh.
No one needs to talk about delaying solar deployment, obviously that would be stupid. No one should be arguing for that, I certainly am not, and trying to do this whole thing where we attack genuine advances just because they aren’t the thing we prefer is super counterproductive to progress. Shameful to do that, no matter how common it is on social media.
This was built as a machine to test fusion, not to generate electricity. It did that, and doing so is a significant advance.
It’s sparking fire in a very specific synthetic scenario which maybe could be useful in making a specific type of fusion reactor.
It’s a critical step, yes, in development of that type of reactor, if we wanted to do so. Currently there is no reason to believe we’d find it worthwhile to do.
But there are literally hundreds more steps just as critical with no known solution, that are likely just as hard before we could actually have net positive energy even in a lab for such a reactor. Even if we found the economics would pan out.
That’s why I’m saying it’s a small step and we’ve got miles to go - because we do.
You’re pointing out some of the next small steps.
But those won’t get us to even having the energy balance positive on paper.
making lasers 100x more efficient for one being a notably hard problem, from a physics perspective. Probably even harder than IC fusion. The planned upgrades to lasers will help, but not enough to be close to a positive energy balance.
If the ‘first 90% takes 90% of the time’, we’re now at 2% of that first 90%. But everyone is hyping it up as we just completed it. Which is not true at all.
Honestly, it sounds like a Hail Mary funding push to try to get a new project funded or stop the lab from being shut down.
You want to use lasers to initiate some fusion, you can do that using a tabletop laser lab (although magnetic confinement and big voltages is much simpler).
So this is the first machine where we're sure: it wasn't fusion caused by lasers, it was fusion caused by neutron pressure! Where did that neutron pressure come from? From other atoms fusing!
Note also that the sun does NOT do this. Fusion inside the sun is powered by falling atoms converting their falling energy first into heat then into singular fusion events, which essentially explode and throw a lot of atoms back up. Then the cycle begins again. Fusion inside the sun is a self-limiting reaction, which is why stars don't just blow up once, but "burn" over a long time. All the fusion inside the sun really does is slow down gravity for a little bit, then immediately stop. Gravity is producing the heat from the sun.
The reaction is initiated by the lasers.
You can’t actually use a hammer to initiate it at any useful scale because hammers can’t create the appropriate pressures and temperatures to initiate the process at the scale needed to produce a useful energy output. Which is why the lasers.
So no, the lasers are not immaterial at all.
We still have no idea if we'll ever be able to engineer this thing to produce commercially useful energy. And we probably never will, for all interesting values of "never", the challenges are simply so massive.
The problem is the engineering of how to actually do it in a useful way. They have made some progress towards that but it's still extremely unlikely that laser based fusion will ever work as a power source because: a) they're still two orders of magnitude from break-even from the input side, and b) they don't have a practical way of capturing the energy that's produced at all as far as I understand it.
None of that has changed.
The way to capture the energy and make it into electricity was studied here: https://en.wikipedia.org/wiki/Laser_Inertial_Fusion_Energy
But it had been premature before they achieved ignition. You don’t build a boiler before you even have been able to spark a flame.
https://en.wikipedia.org/wiki/National_Ignition_Facility#/me...
Credit: Mark Herrmann/LLNL
From this article: https://physicstoday.scitation.org/do/10.1063/PT.6.2.2022121...
Clear qualitative difference.
Additionally, this is laser energy, but the lasers aren’t used directly. They produce X-rays which are the ones that actually drive the ablative implosion of the fuel pellet. If you used X-rays directly, the gain value would be MUCH higher… I think by that measure, they would’ve achieved Q=1 back in 2013?
Note that hey COULD use the lasers directly to drive implosion but haven’t yet. The Hohlraum/X-ray/indirect method I think produces more consistent lighting on the target, and is more analogous to the operation of an H-bomb, which is partly what this entire process is intended to replicate. They may do future experiments to try direct drive, in preparation for actually using this as a power production method and improving the efficiency dramatically… in combination with far higher efficiency modern lasers, this could enable Q high enough for net electricity production.
A real plant would need target yields 100 to 1000 times larger, with all the engineering issues that would entail.
It's so unlikely even under the sun's massive gravitational and heat that the power output is about 270W/cubic meter-- compare to human metabolism or an energetic compost pile, which is over 1000W/cubic meter.
We actually have to do a whole lot better than the sun, under far less favorable conditions-- to have practical fusion for energy generation on Earth. Inertial confinement fusion ignition (and to a lesser extent, thermonuclear weapons) strongly suggest this is possible.
The fact that black holes exist does not mean that we can spin one up to harvest it's hawking radiation for power. It's not just an engineering problem. That's not what that phrase means.
Hahaha! That is the funniest BS I've heard about it yet! Fusion has always been "only an engineering problem" since the first H-bomb and this approach might actually be the farthest from useful even with is.
You certainly can, if you use a large enough chamber. Pacer was exactly this. You just have to accept high proliferation risk.
My crazy idea would be to use the heat and the pressure of these to pump water uphill. It is of course a crazy idea and you'd have to figure out a way to manage the pressure peak
But it would be very interesting
Hydro is the best, so good in fact that most of the good spots are already taken, because as you said, it requires a very specific geography.
The business model for pumped hydro requires relatively low cost to be economic and if it requires building a giant concrete water retention systems on top of large flat topped hills/mesas, near large drops in elevation, with water retention at the bottom of the large drop that is also really really expensive to build and requires specific geology to be economic.
And if something gets messed up, it’s a huge liability [https://en.m.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Powe...], as it can cause very damaging flooding and be expensive to repair/replace.
Worth doing when there is cheap power that can be stored and sold at higher rates later, but construction costs are really a huge part of it.
I'm fairly certain we have these multi level semi natural systems here in Norway, but I am not sure if we use them for pumped hydro.
(Og course, if one doesn't care about ecology, one of those levels can be the sea.)
This is a great idea, not crazy.
It ignores the steampunk future that awaits us all!
In 1972 they decided it wasn't economical based on fuel price compared to yellowcake, but fissile fuel isn't the primary cost of fission power and the engineering costs of pacer would seem to be much lower.
If you relax one of those requirements, then it becomes instantly clear that limitless cheap energy is possible. For a somewhat absurd example, imagine that we build Pacer plants in space instead of on Earth. There's no longer any size constraint on the blast chamber. You can go to triple-stage (like Tzar Bomba) or more designs, at which point the fusion fraction gets extremely close to 100%, and the cost per unit energy becomes somewhat hard to fathom. But on Earth, it still would have been expensive.
If this result is "useless" and "shouldn't be news," then the whole field of MCF and all the start-ups are even more "useless" and should be even less as news, because a small non-zero number is still larger than zero.
Contrast MCF with "inertial confinement fusion"[2] (ICF), a different (and apparently competing) approach taken by the National Ignition Facility in this latest announcement.
1. https://en.wikipedia.org/wiki/Magnetic_confinement_fusion
2. https://en.wikipedia.org/wiki/Inertial_confinement_fusion
Yes, I'd agree with that statement that it's only an engineering problem, but with a laser energy of 2 million joules and a fusion yield of only 3 million joules and an overall input of nearly 300 million joules to produce the lasers then I've no expectation of ever seeing a total net positive output in my lifetime let alone fully established working fusion plants providing power to ordinary customers.
Moreover, compare the overall 'negative' efficiency of this experiment with the actual positive efficiencies of existing generation systems: solar: 20+%, combustion: 20%-40%, mechanical/electrical turbine: >97% and so on and we see there's three or so orders of magnitude to catch up upon.
The task may not be impossible but don't hold your breath.
https://en.wikipedia.org/wiki/Mercury_laser
https://www.laserfocusworld.com/test-measurement/research/ar...
The second link has more details, but they show a 0.7% efficient NIF vs. a 7% efficient Mercury laser in the tiny little chart graphic -- which would reduce the energy for this experiment from 285MJ to 28MJ. This is way outside my area of expertise, but from what I understand, the same general tech that LLNL used to generate the HAPLS for Europe's laser research could be applied to the Mercury-like lasers and increase efficiency even further.
https://www.techbriefs.com/component/content/article/tb/insi...
[0]https://en.wikipedia.org/wiki/National_Ignition_Facility#
Since a lot of modern laser research now overlaps with advanced semiconductor manufacturing, the competing systems are much more mature. Here's a good rundown, but experts think that it's plausible to use even up to 20% efficient systems. Rather than using the laser to first generate xrays - these "direct drive" systems deposit the energy from the lasers directly on the pellets.
https://physicstoday.scitation.org/do/10.1063/pt.6.2.2021102...
We've been able to reliably trigger stable fusion in controlled experimental facilities since before I was born in 1966. People have literally been claiming fusion power is just an engineering problem longer than my entire lifetime, and I'm no spring chicken. Ring me when they reach engineering breakeven, although optimistically the chances are it'll be my grandkids that take the call.
Well, sort of. This is "theoretical breakeven" - the reaction generated more energy than they put in. "Technical breakeven", where you generate enough power to run the thing, is 2-3 orders of magnitude away. It's not at all clear that pulsed fusion like this is a viable power source even if it reaches technical breakeven.
The magnetic containment people are still struggling, but making progress. For a long time, everybody was looking for some clever magnet geometry that would yield stable plasmas, with limited success. Maybe active control will work. There are now people throwing machine learning at the problem.[1]
[1] https://news.mit.edu/2022/fusion-machine-learning-turbulence...
Not in the Expanse "pellets explode and produce electricity" way but in the Project Orion "explode nuclear bombs behind a shock absorber and ride the shockwave" way [1]. Just that this allows you to build much smaller and more manageable spacecraft (important since you probably still want to reach orbit with more traditional propulsion)
1: https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propuls...
What we have are a bunch of R&D people, some of which are using ingredients for which the entire world combined possesses enough fuel to run a single power plant for only two months, and then we’re out.
https://youtube.com/watch?v=_bDXXWQxK38&t=1081s
They talk about why ITER has no viable fuel source, and about how they (Helion) are going to have to run two configurations of fusion plants in order to source their own fuel. One that produces a 10% power surplus, undesirable neutrons and the fuel for their power plants. They didn’t say anything but I suspect they’ll end up coming up with a use for the neutrons, perhaps making fuels for other processes. Someone will likely eyeball that waste heat as well.
Secondly I’m not sure what you mean by saying this experiment has only academic differences with a thermonuclear weapon. It seems the only similarity is they both generate a fusion reaction. The latter is essentially multiple bombs strapped together which is quite different practically.