Polywell fusion

[Sibling Zono (anon1mat0)]

I'm on my phone and far from home to check in detail but IIRC some spaceprobes (the voyagers I think) use thermocouples with mini fission reactors despite alpha emmisions from the reactor. My hunch would be that the amount of alpha radiation would have to be humongous to do a direct-to-electricity conversion. Am I missing something?

[Bob in a quantum-state-of-faith]

I'm on my phone and far from home to check in detail but IIRC some spaceprobes (the voyagers I think) use thermocouples with mini fission reactors despite alpha emmisions from the reactor. My hunch would be that the amount of alpha radiation would have to be humongous to do a direct-to-electricity conversion. Am I missing something?

I don't think so.

The Russians also experimented with, and actually produced as far as I know, a "reactor" based on fissionable material and germanium solar panels, if I remember my history.

They made any number of really large spy satellites powered by nuclear power sources-- solar was too weak for the active radar sets on those.   In the 80's a friend of mine was in the US Army in Texas, and sometimes worked on moderately secret projects.  They had to be aware of the satellite's schedule, so as to avoid being in it's active path with certain activities.

Anyway, the joke was that if you were caught outside when it went overhead, you'd better bring sunblock to avoid sunburn from it's powerful radar...

[Alpaca]

With respect to alpha particles -

Last time I formally was taught about nuclear stuff was in physics two years ago, but if I recall correctly, the "clean" nature of fusion depends on the constituent atoms chosen to fuse. Some combinations form a stable heavier isotope perfectly, some form a heavier isotope plus some junk like alpha radiation, and some can form an unstable or metastable isotope that then decays to produce some junk.