Big Polywell size.

Discuss the technical details of an "open source" community-driven design of a polywell reactor.

Moderators: tonybarry, MSimon

D Tibbets
Posts: 2775
Joined: Thu Jun 26, 2008 6:52 am

Post by D Tibbets »

I should add that fusing heavier high Z (lots of protons and electrons in the molecule) elements can deliver energy up to iron, but the increasing losses (Bremmstrulung) might become the limiting factor before iron is reached. It depends on just how well the evolved Polywell can focus the fuel ions to maximize the fusion yield to bremstrunlung loss ratio (one of the basic conditions/ assumptions nessisary for the Polywell to operate beyond D-T or possibly D-D fusion.

Dan Tibbets
To error is human... and I'm very human.

chrismb
Posts: 3161
Joined: Sat Dec 13, 2008 6:00 pm

Post by chrismb »

D Tibbets wrote:I should add that fusing heavier high Z (lots of protons and electrons in the molecule) elements can deliver energy up to iron,
Nickel-62 is the end-point for energy out of something. But 62Ni is quite a rare outcome, for all the various fusion and fisison reactions possible, so turn out to be quite rare in the universe.

In regards > 15N fusion, most of the usual reactions are mediated by the electromagnetic force, rather than the strong force. p15N is one of the highest Z that turns out a strong nuclear product (an alpha) at an energy higher than it needs for the reaction to occur (of the order of ~1MeV input for ~4MeV output).

p12C is one such Em mediated reaction - produces X-rays rather than hot nucleon products, so is useless for 'normal' reactions but instead produces a 13N that decays with neutrinos and positrons. The positrons result in 511keV energy , of course, but seeing as you have to put >~1MeV into the reaction then you can see it ain't gonna pay back. Any of these higher z reactions *do* produce [thermal] energy but it has to be a near 100% efficiency capture back into heating up the fusion products inside a very well thermally insulated volume: viz. inside a star.

Post Reply