4 ms·

Lex Fridman had an interview with his dad on his podcast a while back. His dad is a plasma physicist and had some interesting thoughts on your point here: htt

by jcims 5y ago

Lex Fridman had an interview with his dad on his podcast a while back. His dad is a plasma physicist and had some interesting thoughts on your point here: https://www.youtube.com/watch?v=6JipQNWuYnA&t=10217s https://www.youtube.com/watch?v=6JipQNWuYnA&t=10217s In summary, he thinks hot fusion is obviously possible but the system is too complex to ever scale. He has an interesting idea about doping atoms with muons to increase the overall density of the material. I don't know that there's any substance to it, but I like his perspective that the ultimate solution will likely come out of nowhere by an individual or small team that's allowed to pursue wild ideas.

api 5y ago
Interesting. If solar/wind and batteries continue their downward price trajectory we may never see commercial hot fusion on Earth, not because it's impossible but because it could never be economically competitive with the giant free gravitational confinement reactor at the center of the solar system. Fission and fossil fuels would eventually be eaten too, though I think you might still see some use of them in regions that are isolated and have very poor solar and wind options. Fusion would be very important in the far future for the potential of interstellar probes or even interstellar migration. AFAIK it's the only power source that could enable flight at a meaningful (e.g. double digit) fraction of the speed of light.
RBerenguel 5y ago
Note: haven't watched the video (I might). Using muons as catalyst is "old news" [0], it didn't seem to work well enough in experiments. It was used by Arthur C. Clarke as the energy source for the ships in 2061: Odyssey III [0]: https://en.wikipedia.org/wiki/Muon-catalyzed_fusion https://en.wikipedia.org/wiki/Muon-catalyzed_fusion
- jcims 5y ago
  Oh wow! Thank you for this! I clearly didn't understand the mechanism that Alexander was discussing, definitely not that the change the atom was sufficient for it to effectively self-fuse and release the muon afterwards. So all we need for a Mr Fusion on our Delorean is a portable muon gun. :P Edit: Video from MinutePhysics - https://www.youtube.com/watch?v=aDfB3gnxRhc https://www.youtube.com/watch?v=aDfB3gnxRhc
  - RBerenguel 5y ago
    IIRC creating muons is not that hard, but the fusion ratio was too small anyway. I still think combining it with some weak containment might work… I guess it doesn't and this is why it's not worked on anymore
    - jcims 5y ago
      Yeah I don't know anything at all but it does make me wonder if you could use the energy created by the muon-catalyzed fusion to push a lower-temp hot plasma into fusing over the edge. Almost like hierarchical catalysis of fusion. Again per your observation, if it had any value we would do it so i'm missing one to many major things. I just enjoy thinking about it.
baybal2 5y ago
There is no "ultimate solution" The biggest point which stood the test of time, and is the easiest to validate is that if you build a TOKAMAK big enough, it will work. Plasma instability decreases with the device size, and efficiency rises. Every experiment so far validated this.
- jcims 5y ago
  Sure. Definitely wouldn't advocate we stop following that path.

by jcims 5y ago

api 5y ago

Interesting. If solar/wind and batteries continue their downward price trajectory we may never see commercial hot fusion on Earth, not because it's impossible but because it could never be economically competitive with the giant free gravitational confinement reactor at the center of the solar system. Fission and fossil fuels would eventually be eaten too, though I think you might still see some use of them in regions that are isolated and have very poor solar and wind options. Fusion would be very important in the far future for the potential of interstellar probes or even interstellar migration. AFAIK it's the only power source that could enable flight at a meaningful (e.g. double digit) fraction of the speed of light.

RBerenguel 5y ago

Note: haven't watched the video (I might). Using muons as catalyst is "old news" [0], it didn't seem to work well enough in experiments. It was used by Arthur C. Clarke as the energy source for the ships in 2061: Odyssey III [0]: https://en.wikipedia.org/wiki/Muon-catalyzed_fusion https://en.wikipedia.org/wiki/Muon-catalyzed_fusion

jcims 5y ago
Oh wow! Thank you for this! I clearly didn't understand the mechanism that Alexander was discussing, definitely not that the change the atom was sufficient for it to effectively self-fuse and release the muon afterwards. So all we need for a Mr Fusion on our Delorean is a portable muon gun. :P Edit: Video from MinutePhysics - https://www.youtube.com/watch?v=aDfB3gnxRhc https://www.youtube.com/watch?v=aDfB3gnxRhc
- RBerenguel 5y ago
  IIRC creating muons is not that hard, but the fusion ratio was too small anyway. I still think combining it with some weak containment might work… I guess it doesn't and this is why it's not worked on anymore
  - jcims 5y ago
    Yeah I don't know anything at all but it does make me wonder if you could use the energy created by the muon-catalyzed fusion to push a lower-temp hot plasma into fusing over the edge. Almost like hierarchical catalysis of fusion. Again per your observation, if it had any value we would do it so i'm missing one to many major things. I just enjoy thinking about it.

baybal2 5y ago

There is no "ultimate solution" The biggest point which stood the test of time, and is the easiest to validate is that if you build a TOKAMAK big enough, it will work. Plasma instability decreases with the device size, and efficiency rises. Every experiment so far validated this.

jcims 5y ago
Sure. Definitely wouldn't advocate we stop following that path.