When you think about which temperature or energy level you need to heat a fusion fuel compared to what it gives when it fuse, then it seems lika piece of cake to make fusion. The most common example is D-T fusion where the products ned to be heated to about 15 keV and if it fuse gets 17,6 MeV. So the process theoretically gives over 1000 times more energy then it takes, and it is possible to use even lover temperatures. For boron + proton the heating takes 123 keV and gives 8,7 MeV still 70 times more heat out then in.
So where does it goes and why bother. It bothers me because it must be the main reason why it is so hard to achieve fusion. Even if it’s possible to convert the X rays to electricity for example, all the losses more or less blows out the fire. So there is of great importance to reduce losses, and do so in the process. I know that some heat goes away by convection and some by radiation. Fuel that never burns is also a loss. There is also much talk about heat transfer between electrons and ions.
So what does the losses cause.
Convection spread the heat and that is god, but it also takes it away from the reaction.
The radiation goes out, and very little will be absorbed. Converting X rays to electricity is great, but that doesn’t help the reaction, or rise the temperature in the reaction zone.
Heat transfer between electrons and ions I don’t really knows what it cause. Does it lead to radiation or does it speed up either kind of the two particles, anyone.
What proportions of the losses are we talking about. Which loss is the biggest? That I’m very interested in. Is there several big sources of loss or do one of them dominate? If it’s one source of losses it must be that one to concentrate on.
What to do about it.
For radiation I think the only thing you can do is to keep the hot zone as small as possible. If you look at what a black body radiate at 100 milj K it’s tremendous amounts. A surface of 1 sqm can radiate in the magnitude of 10 power 24 W. Usually the gases for fusion are more diluted and not a black body, but still at high temperatures it matters. Power equals to surface, so keep the surface small.
For fuel that don’r react, longer time, or temperature or pressure or everything. What else could you do.
To reduce convection loss the temperature gradient need to be more flat. How Im not sure
How do you look at it. What can you add to the problem or what do you suggest that could be done.
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