41–50 of 285 posts
> and most rely on a deuterium-tritium thermonuclear fusion approach that requires the creation of ludicrously hot temperatures, much hotter than the surface of the Sun, at up to 15 million degrees Celsius (27 million degrees Fahrenheit). Surface of the Sun - 6000 C Center of the Sun - 15000000 C
> and most rely on a deuterium-tritium thermonuclear fusion approach that requires the creation of ludicrously hot temperatures, much hotter than the surface of the Sun, at up to 15 million degrees Celsius (27 million degrees Fahrenheit). Surface of the Sun - 6000 C Center of the Sun - 15000000 C
> The temperature in the corona is more than a million degrees, surprisingly much hotter than the temperature at the Sun's surface which is around 5,500° C
This seems.. too good to be true? I don't have the Physics chops to untangle the likelihood of this tech and the credibility of the process and its authors, so I'm hoping the HN crowd will be able to pad out the story behind this. Certainly, from my layperson's perspective, their website isn't exactly encouraging... https://www.hb11.energy/ - ed re: last line - "books and covers, and all that"
-Conversion efficiency of laser energy into ion (proton) kinetic energy
-TNSA accelerates mainly the contaminated layer on the back of targets, which may not be a big deal if you are interested in accelerating protons
-TNSA protons are not beam like. They do not have a uniform kinetic energy, and they have a wide angular divergence.
-Various laser related issues (prepulse, focal spot size/shape).
I also anticipate that it will have the same engineering problem as ICF/NIF, in that it will need to continuously replenish targets.
This seems.. too good to be true? I don't have the Physics chops to untangle the likelihood of this tech and the credibility of the process and its authors, so I'm hoping the HN crowd will be able to pad out the story behind this. Certainly, from my layperson's perspective, their website isn't exactly encouraging... https://www.hb11.energy/ - ed re: last line - "books and covers, and all that"
I can’t tell for sure from the article but I think they are accelerating protons with TNSA (target normal sheath acceleration). I worked in a lab in undergrad that was doing something similar, except with lithium instead of boron. The main challenges that I recall from a decade ago with TNSA are (WARNING: there almost certainly has been progress since a decade ago): -Conversion efficiency of laser energy into ion (pr…
Can someone explain why this is considered fusion? The reaction involves shooting a proton (hydrogen) at a boron nuclei and outputting 3 alpha particles. That seems more like the nuclei being split apart than fused together.
Start here: https://en.wikipedia.org/wiki/Aneutronic_fusion (TLDR version: proton-boron fusion is a less energetically efficient alternative to 3He fusion, but with the howlingly significant advantage that boron -- the fuel -- is lying around in heaps and drifts on Earth, rather than being so exotic a substance that annual global production is measured in single-digit kilograms and a significant energy economy would…
This seems.. too good to be true? I don't have the Physics chops to untangle the likelihood of this tech and the credibility of the process and its authors, so I'm hoping the HN crowd will be able to pad out the story behind this. Certainly, from my layperson's perspective, their website isn't exactly encouraging... https://www.hb11.energy/ - ed re: last line - "books and covers, and all that"
This seems.. too good to be true? I don't have the Physics chops to untangle the likelihood of this tech and the credibility of the process and its authors, so I'm hoping the HN crowd will be able to pad out the story behind this. Certainly, from my layperson's perspective, their website isn't exactly encouraging... https://www.hb11.energy/ - ed re: last line - "books and covers, and all that"
Check the publications page for the encouraging part. They might be wrong but they're doing real science. I've personally spoken to a fusion scientist who thought they might be on to something. Exponential progress does sometimes have results that seem too good to be true. In this case the progress has been in picosecond lasers, which for a while have been getting ten times more powerful every three years or so. What…
I checked the publications page and so far I'm not seeing any real theory here. That doesn't mean it's wrong, but it certainly feels weird. The most in-depth equation I saw in any of their linked papers is the definition of the electromagnetic field tensor.
I'm not saying you couldn't develop a fusion reactor by doing purely experimental work with bleeding-edge laser technology. But I'd feel a lot more confident if they were to produce, for example, some kind of prediction of their net power, or a relation between e.g. laser power and fusion yield, or some other quantitative prediction about something.
For example, I'm not sure what prediction they exceeded by a factor of a billion in TFA. Shouldn't you mention that somewhere?
Another poster mention's Todd Rider's thesis, a famous barrier to creative fusion. In this particular case I think the way they evade Rider is by using higher laser powers and shorter reaction times than Rider considered to be possible. One of the important exceptions Rider acknowledges (and that I remember) is ultradense fusion; ultrafast fusion seems to be at least similar in principle.
There is a warning sign. Without actually running the number, I believe the energy generated by the proposed HB11 fusion should be several order of magnitude higher compared to the electric energy alpha particle can carry. So extreme hot temperature will be created regardless. Edit: actually read the paper :) From the paper: H + 11B = 3 x 4He + 8.7 MeV when alpha particle absorb the electron to become helium, it can…
My nuclear fusion physicist friend is very sceptical.
There is a warning sign. Without actually running the number, I believe the energy generated by the proposed HB11 fusion should be several order of magnitude higher compared to the electric energy alpha particle can carry. So extreme hot temperature will be created regardless. Edit: actually read the paper :) From the paper: H + 11B = 3 x 4He + 8.7 MeV when alpha particle absorb the electron to become helium, it can…
These are IMO the fundamental questions.