How are positrons used for fusion propulsion?

[Ozne]

Hi,
I recently came across Positron Dynamics, a company working on a fusion propulsion system.
You can watch this presentation given at Breakthrough Discuss 2018. They also got a grant from NIAC.
Rather than trying to create and store positrons, they use Na-22 as a source. They also patented, built and tested a moderator to cool the positrons (they claim 60% efficiency compared to current 0.7%).
The positrons are then used to catalyze fusion (I'll get to that) in a "dense state of deuterium" in a metal lattice. The resulting charged particles are used for propulsion with magnetic nozzles while the neutrons are used to create more Na-22 from Kr-78.
In spite of the use of the metal lattice, this is not a cold fusion concept as the ignition is supposed to be provided by the positrons.
Now, how are positrons supposed to catalyze a D-D fusion reaction ? A previous thread in this forum seems to be skeptical about this.
At 7:43 of the video I mention they seem to indicate that the gamma rays from the annihilation can induce fusion directly (by heating ?). However, in another place (linked from their web page, scroll down), the mechanism seems to be quite different (at least to me and my limited knowledge) and strange. Here the positron annihilation is supposed to produce pions and kaons. The latter decay into muons that then catalyze the fusion reaction. This is a surprise to me since I always thought that the annihilation produced gamma rays. Maybe this other reaction is less likely but still useful for propulsion. I don't know.
Any ideas ? Is this plausible/possible ?
Thanks.

 

[PeterDonis]

Here the positron annihilation is supposed to produce pions and kaons.

That's going to be tough since the total energy from the annihilation is just over 1 MeV (positron mass + electron mass--kinetic energy is negligible since the positrons and electrons are basically at room temperature), but pions mass about 139 MeV and kaons mass about 495 MeV. (And to satisfy conservation laws you would need to produce a pion-antipion or kaon-antikaon pair, doubling the energy required.)

Is this plausible/possible ?

Don't think so. See above.

 

[Ozne]

Thanks.
Soon after posting this I found this other thread which shares :

• your skepticism about kaon creation (see the very last post). But why would Positron Dynamics link to this in the last link in their web page ?
  
• my perplexity about the mechanism of a positron inducing/catalyzing fusion. There is something clearly missing in their talks about this fundamental point,

Again, if someone has a plausible mechanism for the latter, feel free to share it.

 

[PeterDonis]

Soon after posting this I found this other thread

We can't comment on discussion threads in other forums.

why would Positron Dynamics link to this in the last link in their web page ?

I have no idea. We can't speculate on their motives.

if someone has a plausible mechanism for the latter

There isn't going to be one, given the obvious flaw I've already stated with the proposal.

Thread closed.