Sam Cohen’s Rotating Magnetic Field experiments have shown higher temperature and reasonably long-lived FRCs. His vision is steady operating, 3He systems, atleast at first targeting propulsion. As you dial up the Helium percentages, the neutron output goes down, though the required ion temperature goes up. Princeton Satellite Systems has several NASA programs looking at the propulsion applications.
The scheme involves significantly non-maxwellian ion distributions, so "temperature" isn't really appropriate. In particular, 3He ions get pumped to higher energy than D ions, which helps suppress DD fusion. They claim the scheme is consistent with Rider's limits on energy circulation in non-maxwellian plasmas.
1% of all deserts is only correct if you are talking about only today's electricity use. Even moderate growth and actually solving energy, not just the electricity subset drives these percentages much higher. To get US centric again, NREL published an optimistic 2016 report suggesting that the maximum rooftop solar capability could ever meet is 40% of electricity. That's 15% of today's energy use in an electricity heavy country.
>1% of all deserts is only correct if you are talking about only today's electricity use. Even moderate growth and actually solving energy, not just the electricity subset drives these percentages much higher.
U.S. electricity usage has been flat for the past 10 years[0] despite a cumulative GDP growth of 34% over the same period. I'm not saying the same trend will continue to hold, but you are overestimating future electricity usage growth.
6% is about the best we can do with a closed cycle. Extra-terrestrial sources could push those numbers even lower by running up to a pure D-He3 reaction.
Yep. I think 6% is pretty good...it's enough so you don't need a heat cycle to extract electricity, and dealing with the neutron damage is easier than going to Uranus. But working fusion reactors probably also means working fusion rockets, and if we find ourselves going to Uranus anyway, all the better.
If we get really good at fusion we could also use boron fusion. It uses the most common isotope of boron, which is plentiful on Earth, plus regular hydrogen, and the main reaction is aneutronic. There'd be some minor side reactions but it'd be under 1% of energy as neutron radiation, probably better than you'd get with deuterium in the mix.
Thanks FiatLuxDave, I think you are exactly right. Prototype/design cycle time is a huge issue with fusion, fission, and many other energy technologies. No matter how good your idea may be, you have to be able to build, test, iterate, prove, and commercialize it quickly (and ideally, cheaply, but I would argue quickly is even more important). In energy, the physics make everything work better at large scale so it is easy to fall into the "build it bigger" trap.
Interesting: ... "scientific research can provide some measure of confidence that short-term, acute exposures up to about 1-2 T [1000-2000 milliT] should be safe... However, it is not possible to determine whether there are any long-term health consequences even from exposure in the milliT range because, to date, there are no well-conducted epidemiological studies with sufficient power to be able to come to any conclusion on this, and there are no good long-term animal studies."
Helion here. There are pretty big differences. They did get the high Beta and compact/modular parts right. The primary differences are that Helion operates entirely pulsed with simple non-superconducting magnets. That allows us to go to higher temperatures, cleaner fuels, directly recovery energy, and if everything works as planned should eliminate the wall concerns and need for particle beams.
I do think what they are doing is interesting. If its like the Gas Dynamic Trap or Tandem Mirror it has promise, atleast from the fundamental physics point of view. Researchers in Novosibirsk had encouraging results in the last 5 years. They still have a long road ahead to get to fusion-relevant temperatures, but we are staying tuned to this one.
If you really are Dr. Kirtley let me say you have one of the most, if not the most important job in earth right now. Fusion energy has the potential to stop wars and re-start the space revolution. I wish you the best.
I'm all about the space revolution, but the only way to stop wars is to have one so big there is no one left to wage them. In a way, fusion does have that potential, but I suspect you were going for something more positive.
Of course it will not stop all wars, but it will stop most oil-related wars. You still will have resource-related wars like cultivable land, and fresh water but with the space-revolution soon humanity will have plenty of land and water too.
Well... if fusion energy is abundant, the price of oil will drop rather abruptly. A lot of people in a lot of places, where the population has been expanding, and there is a lot of religious extremism and political instability and modern weapons, will have to find a new way to feed themselves. And someone to blame if they can't. So I'm not that optimistic it will stop any wars.
Aha thanks for the explanation, that does make things clearer. Also a huge thanks to you for being at the forefront of technology. I consider energy research the single most important thing we can do for humanity, and I'm incredibly grateful to see real progress on fusion in my lifetime.
Great reply. The wiki also has a long discussion about Helium 3. http://en.wikipedia.org/wiki/Helium-3
Fusion produces neutrons either in the first or secondary reactions, but there are ways to minimize the amount of them and their energy (and damage/radioactivity)to where you don't generate "nuclear waste".
There is an interesting continuum of fusion reactions from pure D-D (which produces little energy, but lots of lower energy neutrons) to D-He3 (that produces some neutrons and lots of energy) to pure He3-He3 (that is called 'anuetronic').
D-D fusion makes Tritium (that decays into He3), Helium 3, or Helium 4 through the fusion process itself, with no breeding.
We believe that there is a correct ratio called Self-Supplied in which you have a small amount of 2.4 MeV neutrons, only deuterium as an input fuel, and the majority of the energy is from the Helium 3 fusion. The hard part is how to separate out the right isotope mixture from the exhaust between pulses.
The best way to make Helium 3 is with Deuterium fusion. Its a very interesting bootstrap question -- how do you build new reactors, if you have to have working reactors to generate fuel?
Yes! Prof. John Slough is the Chief Scientist at Helion and the inventor of the Fusion Engine. UW has been leading the field of 'alternates' fusion for decades.
Our 'About Us' page has a short blurb:
http://www.helionenergy.com/
