Reply To: Newbie pB11 Fuel Questions

[Ivy Matt]

Ivy Matt wrote: Regarding the fuel for Focus Fusion, LPP is considering decaborane (B10H14), which is a solid at room temperature. I’m not sure where they get the B11 from…by enriching decaborane, maybe?

Oy, clearly I’m not a chemist. That’s B(sub10)H(sub14), or ten borons, fourteen hydrogens. And obviously there’s no hydrogen-14. :red: Boron-11 is actually more common in nature, but B-10 and B-11 generally occur together.

NoSmoke wrote: I have read Lerner’s (is that the polite way to refer to him here?)

To be honest, I don’t know. Referring to people by their last name alone in written communication is a habit I picked up in the university. However, it does happen to coincide with his forum name.

NoSmoke wrote: comments that p+B11 goes easier at or around the ideal temperature for that reaction but, does it necessarily follow that D+D (for example) would not be as favourable (as p+B11) at the ideal D+D fusion temperature (i.e. a much lower and presumably easier to reach temperature)? Perhaps it has to do with the greater magnetic field that accompanies the p+B11 fusion conditions (?). Anyhow, that’s why I was wondering earlier if D+D could be a possible fall-back route to take.

D+D fusion is certainly easier to achieve (in terms of kilovolts and stress to the spark plug insulators), but I’m not sure about net power from D+D fusion. The reaction produces neutrons and three types of positive ions: protons, tritium*, and helium-3. I imagine the ions could generate electricity directly, and the neutrons could generate electricity the old fashioned way, but I don’t know enough to say how feasible either or both methods of electrical generation are. And there would still be a nuclear waste problem.

However, when I said that heavier gases achieve fusion more easily, I was referring to this:

To see what the consequences of the magnetic field effect are for DPF functioning, we
first use a theoretical model of DPF functioning that can predict conditions in the plasmoid,
given initial conditions of the device. As described by Lerner [12], and Lerner and Peratt
[13], the DPF process can be described quantitatively using only a few basic assumptions.
Using the formulae derived there, Lerner [1] showed that the particle density increases with μ
and z as well as with I, and decreases with increasing r. Physically this is a direct result of the
greater compression ratio that occurs with heavier gases, as is clear from the above relations.
Thus the crucial plasma parameter nτ improves with heavier gases.

See section 3: “Conditions In DPF Plasmoids”. I’m not a physicist, so I have little idea how well my ideas match reality (or physics models, at any rate), but I picture the magnetic field “squishing” the plasmoid, and it makes sense to me that the heavier the element(s), the denser the plasmoid would be. Thus, the Focus Fusion device not only uses plasma’s instability against itself, but it also uses boron’s relatively high (compared to hydrogen) atomic number against itself.

*Speaking of tritium, I recall that this question came up in the Talk Polywell forums: What happens to the tritium that is produced in the current D+D fusion tests? Is there very much of it? I suppose this question would come up with regard to any research program involving D+D fusion, but I didn’t have a satisfactory answer with regard to the LPPX.