Some of you like me may have picked up on the story of this neat form of fusion research, maybe even from the same google video that sparked my interest in this spherical not donut shaped plasma research. Only the size of a clothes dryer, these little fusion reactors have a simplicity that Tokamaks don't. For about 3 years I have followed developments in the research with anticipation.
And now in President Obamas budgethe looks to fund polywell with a line item, instead of thru a research slush fund from the Office of Naval Research (Bush didn't fund it and the ONR thought it was too promising to not fund).
Dr Bussards developement of the Polywell started in the 1980's with DARPA funding, then Navy funding. The Navy wants Polywell as a replacement for shipboard fission nukes, 100,000 to a million times less radioactive, and at as little as 30 ft across for an entire plant (1000-1200MW) using the PB-11 reaction. And in some circles, folks relish the idea of a compact 1200MW to power some laser or something, but thats a whole nother diary or 2 or 3.
Dr Bussards November 9, 2006 funding appeal in the Google video became moot when the Navy decided to build/fund anew, the short circuited and burnt out WB-6 would be replaced with WB-7. I was thrilled, and then Dr Bussard passed after battling cancer. Dr Nebel from Los Lamos came over to continue the work.
WB-7 was built, run, tested, poked, proded and underwent a peer review process headed up by former US Atomic Energy Commission Director Robert Hirsh. Then during the winter of 2008-2009 some (200k)DOD funding paid for the building of a new Ion gun, some additional instrumentation, and remounting the magnets in a way that increases efficiency. To be known as WB-7.1. Dr Nebel has been blogging and keeping everyone as best informed he can, recently related that the nubs between the coils were creating electron loses. He inferred that this was the major loss mechanism they found in testing and sounded very upbeat.
Above:WB-6 magnets. Wiring was routed thru the 4 standoffs seen at the bottom, then from coil to coil thru insulated nubs, a little hard to see here. I'm guessing that standoffs will be used to mount the magnet coils from the vacuum chambers walls, similar to the 4 standoffs in this picture. If installed in the shadow of reaction products they should reduce electron losses.
Above:WB-7. The camera is pointed thru a viewport in the vacuum chamber, parts of 3 coils are seen, and you can just make out one, and maybe a second of the interconnecting nubs.
Now WB-7 was built and tested for about 1.8 million, so Obamas budget having 2 million in it sounds like good news, of a sort, Polywell needs to be fully funded until it works or its a bust. I'd guess 300 million over 5-6 years.
I am guardedly optimistic, though with a Navy publishing embargo results and details just don't see the light of day. I feel that at this point it should be fairly clear that thermalization of electrons is not an issue. Dr Bussard talked about electron re circulation, and that may not be whats happening, electrons maybe surfing the mag field lines and then returning to the potential well, or they could be exiting thru the funny cusp and then returning, sort of recycling. Regardless of the actual mechanism, electrons tend to stay in the system even if they take a break for coffee.
I anticipate that the work on WB-7.1 will be finished later this year, at which point the program will need to deal with 2 issues, True steady state operation and scaling. And switching from DD fuel to PB-11.
Steady state operation.
So far polywell magnets have been nothing more than copper wire in a donut shaped cover. Using Bitter style magnets with Liquid nitrogen cooling would allow for run times on the order of hundreds of seconds. And a Polywell like this would be capable of accessing the regime where the PB-11 reaction occurs. PB-11 has a resonance spike around 550Kev, just about the lowest temp/energy where one would have a chance of getting the Pb-11 reaction to work. And thats only 55KeV in the potential well. Eventually super conducting magnets will have to used for a full scale proof of commercial viability.
Scaling.
The magnets on WB-6 and 7 are only about 30 cm across, theory says if you double the size of the magnets, you will get 128 times more power output. This would be easy to check, build a Polywell thats got 60 cm magnets. If the scaling is remotely to theory, then build a Polywell that should get net power. At talk polywell.org, they've taken to calling it WB-100, a 100MW goal.
Dr Bussard thought that the magnets in a 1000MW PB-11 fueled polywell would be 3 meters across, maybe fitting into a 5 meter vacuum chamber, which fits into a 10 meter building. Dr Bussard also spoke of his concern about peak oil, and the need to develop another energy source, his personal wish was to go to Mars. Or least see one of his designs take someone else to Mars.
Nuclear fusion will give us the solar system, Saturns moon, Titan in 76 days, Mars in 38 days. The power to use space based metals and minerals in space based blast furnaces to form shapes/modules/frames for space ships, space stations. A new generation of industrial infrastructure will be built, in space. Nuclear fusion will go a long way to making liquid fuels obsolete.
Nuclear fusion will make humans a space faring race.