I've been following developments in Polywell fusion for about 2 years. Dr Nebel is running the Polywell program after its founder DR Bussard passed away last year. In short all the critics have been swept away over the last few years, as each new machine brought forward new positive developments. The lab in Santa Fe is home to a small Polywell test fusion reactor undergoing test runs over the last 6 months. THe US NAvy has funded this reactor to the tune 1.8 million bucks, and they maintain a publishing embargo on data. But Dr Nebel has been blogging, and recently dropped a bombshell in 2 parts"
- We're getting data.
- We might as well build the next one in that size range
The size range DR Nebel is talking about is a 1.5 meter 100 MW net power fusion reactor.
I really thought much more research was in the works, but I now understand where Dr Nebel is coming from. But let me backtrack:
Currently the fuel is "puffed" in gaseous form, there is no carburetor. The fuel ions are puffed in, the plasma lights up, some fusion occurs, and the magnets get very hot. All this occurs in under a second. It takes hours for the magnets to cool down for the next run. Superconducting magnets would solve this problem, but at a much higher cost.
Theory says if you scale up the 35 cm magnets to 2 meters, you will have a 500 mw net power reactor. This scaling theorrry is unproven. A carburetor also needs to be built. and there is a possibility that slightly different designs can be more efficient.
To address these concerns I thought these 3 should be built simultaneously
1)WB-8, 35cm LN2/carburetor/steady state
2)WB-9, 70cm pulse mode
- WB-10, 35 cm truncated dodecahedron
Bussard thought the truncated dodecahedron might be better than the truncated cube of WB-6. Reason, the cusps are smaller, the triangular corners of the "cube". The electrons would have a tougher time escaping, in essence, the electron gyro radius is the same, the little spiral the electron makes as it travels, while the cusps are smaller in the truncated dodec.
Just thinking out loud here... do the each of coils have to be a perfect torus?
Good thought, a perfect torus, maybe not.
Lets squeeze it, and the cusps are even smaller now. Since Polywell recirculates the electrons, this sort of thinking is no longer paramount. But ya never know, and for 3 million, why not build one to see what the difference in performance might be.
or is the shape of the well the really important part?
Todd Riders masters thesis says IEC/Polywell cant go to net power, because of maxwellian thermalization. This was based on a square well, like at the bottom of this graphic:
This means a wide well, not good for Ion focus, as the ions will see a wide target, as they fall to the center. A Parabolic well coaxes the ions to a smaller target, a spiked well would really focus the ions to a single point. Bussard had been working to get a parabolic well as far as I know. Lots of things about polywell seem to be compromises between many factors/issues, in this case we have a square well at one end, at the other a spiked well, and in between the parabolic well.
Nebel is that enthused by the data they're getting? :wow: Just the fact that he's willing to mention building a full-size device that generates net power is more than I expected to hear from him at this point.
I had read Nebels comments about going for the 100MW net power size, but it took a week to sink in. He said hes getting data.
Due to the publishing embargo we knew he couldn't tell us WHAT DATA. (neutron counts)
so a machine about 1.5M in diameter would in theory be able to produce something around 100MW of net power."
Our contention is that since our projections for a power producing device only require a machine like the one TallDave described, we might as well build the next one in that size range and accept the risk.
But even though Nebel can't yet talk about the data, he's proud that he and his colleagues at Emc2 have gotten so far so quickly.
"By God, we built a laboratory and an experiment in nine months," he said, "and we're getting data out of it."
If it works, it would completely trump- well, everything else.
WB-7 in its vacume chamber during a fusion run earlier this year.
WB-6 in 2005, ready to go in the vacume chamber.
The cure for peak oil & global warming, in one shot. Cross your fingers, I am.
EDIT, to make all the mw into MW. MEGA WATTS.