- cross-posted to:
- technology@lemmy.ml
- cross-posted to:
- technology@lemmy.ml
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Fusion AND room temperature superconductors?! Damn boys, looks like the future is just 10 years away again.
Very cool, I hope it amounts to something in my lifetime.
Even if it doesn’t, I expect that we’ll need fusion power at some point, interstellar travel or something.
https://en.wikipedia.org/wiki/Interstellar_travel
Nuclear fusion rockets
Fusion rocket starships, powered by nuclear fusion reactions, should conceivably be able to reach speeds of the order of 10% of that of light, based on energy considerations alone. In theory, a large number of stages could push a vehicle arbitrarily close to the speed of light.[48] These would “burn” such light element fuels as deuterium, tritium, 3He, 11B, and 7Li. Because fusion yields about 0.3–0.9% of the mass of the nuclear fuel as released energy, it is energetically more favorable than fission, which releases <0.1% of the fuel’s mass-energy. The maximum exhaust velocities potentially energetically available are correspondingly higher than for fission, typically 4–10% of the speed of light. However, the most easily achievable fusion reactions release a large fraction of their energy as high-energy neutrons, which are a significant source of energy loss. Thus, although these concepts seem to offer the best (nearest-term) prospects for travel to the nearest stars within a (long) human lifetime, they still involve massive technological and engineering difficulties, which may turn out to be intractable for decades or centuries.
Researchers at the Lawrence Livermore National Laboratory in California, who achieved ignition for the first time last year, repeated the breakthrough in an experiment on July 30 that produced a higher energy output than in December, according to three people with knowledge of the preliminary results.
The laboratory confirmed that energy gain had been achieved again at its laser facility, adding that analysis of the results was underway.
“Since demonstrating fusion ignition for the first time at the National Ignition Facility in December 2022, we have continued to perform experiments to study this exciting new scientific regime. In an experiment conducted on July 30, we repeated ignition at NIF,” it said.
“As is our standard practice, we plan on reporting those results at upcoming scientific conferences and in peer-reviewed publications.”
Interesting…
What does it say? Paywall in the way…
tl;dr: net positive fusion, though only if you count just the laser energy, not the total power used to run the system
I don’t think that that’s necessarily a huge issue, though, because their aim wasn’t to address that.
That experiment briefly achieved what’s known as fusion ignition by generating 3.15 megajoules of energy output after the laser delivered 2.05 megajoules to the target, the Energy Department said.
In other words, it produced more energy from fusion than the laser energy used to drive it, the department said.
A 2020 article, before the current success or the prior one at the same facility:
https://www.powermag.com/fusion-energy-is-coming-and-maybe-sooner-than-you-think/
No current device has been able to generate more fusion power than the heating energy required to start the reaction. Scientists measure this assessment with a value known as fusion gain (expressed as the symbol Q), which is the ratio of fusion power to the input power required to maintain the reaction. Q = 1 represents the breakeven point, but because of heat losses, burning plasmas are not reached until about Q = 5. Current tokamaks have achieved around Q = 0.6 with DT reactions. Fusion power plants will need to achieve Q values well above 10 to be economic.
So if I understand this aright, on the specific thing they’re working on, they’re at 1.54 as of OP’s article, that is (3.15/2.05), up from 0.6 in 2020. The target is somewhere “well above 10” for a commercially-viable fusion power plant. Still other problems to solve, but for the specific thing they’re working on, that maybe gives some idea of where they are.
To my understanding, here they use lasers to create fusion and the 2 megajoules are emitted by the lasers.
Hence they need waaay more power than is generated to drive their lasers.That is also why this research is not actually aiming at power geration, but at fusion weapons. However, the power framing creates much better press and thus better chances for future funding.
To my understanding, here they use lasers to create fusion and the 2 megajoules are emitted by the lasers.
Yes.
Hence they need waaay more power than is generated to drive their lasers.
googles
It sounds like the additional power is due to energy exiting the system:
https://en.wikipedia.org/wiki/Fusion_energy_gain_factor
Most fusion reactions release at least some of their energy in a form that cannot be captured within the plasma, so a system at Q = 1 will cool without external heating. With typical fuels, self-heating in fusion reactors is not expected to match the external sources until at least Q ≈ 5. If Q increases past this point, increasing self-heating eventually removes the need for external heating. At this point the reaction becomes self-sustaining, a condition called ignition, and is generally regarded as highly desirable for practical reactor designs. Ignition corresponds to infinite Q.
So it sounds like additional power requirements effectively means getting from their current 1.54 to 5.
That is also why this research is not actually aiming at power geration, but at fusion weapons.
I am confident that that is not the case. The US knows how to do fusion weapons and has for decades – that’s what a thermonuclear bomb is, the second stage. That’s a much simpler problem than fusion power generation. You don’t involve lasers or magnets or other things that you use in fusion power generation if you just want a fusion weapon; you only need to force the material together with a great deal of force for a very brief period of time, and then you’re done.
Yes, the US has fusion weapons since the 50s, but Los Alamos still does research on improvements, maintenance, reliance…
The US Department of State on the matter:
Our laser pulls over 300 megajoules off the grid to do these experiments and then converts that into 2 megajoules of laser light and that gave us 3 megajoules of fusion energy.
And here’s a DOE press release from 2022:
This historic, first-of-its kind achievement will provide unprecedented capability to support NNSA’s Stockpile Stewardship Program and will provide invaluable insights into the prospects of clean fusion energy…
That’s why I’m also proud to announce today that I’ve helped to secure the highest ever authorization of over $624 million this year in the National Defense Authorization Act for the ICF program to build on this amazing breakthrough.
Here’s a handy trick that I use on sites such as this one. Between when the article loads and the paywall restricts it, hit a button to display the article in a Reader mode. Safari has this. I believe Firefox does. I think you can get extensions to add such a feature.
When the article loads and then gets paywalled, this works. When the paywall is immediate it doesn’t.
Eu in shambles
