Florida lab to pursue Bussard Polywell and IEC fusion resear

[happyjack27]

Magnetic bottles with cusps has been tried and tried again and it has not been made to work with two cusps, so how will it work with a dozen or more! Polywell has a point to make to prove out, one way or the other, electrostatic confinement of ions by magnetically confined electrons, and we wait [and wait and wait] to see some outcome on that. But to talk of it as a thermal-plasma confining machine is just a bit silly.

you mean with two _point_ cusps. if you're talking e.g. a pair of facing current loops with opposing magnetic fields, yeah they have a point cusp through the center of each loop, but they also have one _huge_ line cusp around the circumference of where the two fields meet. and to make matters worse, the magnetic fields essentially _push_ the particles out of that. it's like if you had a pair of fans facing each other. where does the air go? laterally, and FAST.

i ran a sim with facing magnets. depending on a few parameters you can get the point cusps to show up or what have you, but the general principle is the same:

http://www.youtube.com/watch?v=pHRBbqz_BU4


the competing mag fields eat away at the surface sending the particles flying out the sides.

if, however, you put fans around that escape route, such that you know have 6 fans, one on each end of each axis... well now the air is clearly going to escape out of the corners, but it'll have a much tougher time. you'll get much higher pressure in the center vs. the outside.
and if you run the fan at just the right speed vs. the ambient air pressure... well, theory goes (here the analogy runs up against its limits and you have to shift to mag fields proper) you'll get a pocket of slow moving, higher density air ("electrons") just in the center of the six fans (current loops).

so you see here it is not the addition of point cusps that is dominant, but the removal of line cusps, which are infinitely worse than point cusps.

[ladajo]

Chris,
Rick has publicly stated that confinement is proven. Granted other than the WB6 report, nothing more has surfaced into mainstream. But the public statement of proven, as well as the review panel and subsequent next step funding is a clear enough statement. I, like everyone else would like to see the WB7 numbers, but a face value must accept that they were the same or better as WB6 based on Rick's comments and the current stage.
You keep pointing back to confinement being an issue, whilst the project has moved on. Why?

[Professor Science]

...that and a total lack of any new information.

Amongst our weaponry are such diverse elements as: ... a total lack of any actual information.

So there is no new information in the last few months? What is the tentative schedule for results/reviews/reveals? was the research schedule reaffirmed in august 10 or august 09?

[chrismb]

You keep pointing back to confinement being an issue, whilst the project has moved on. Why?

Confinement of energy? Confinement of magnetic field? Confinement of electrons? It could mean anything (but confinement of a thermal plasma?).

[ladajo]

You keep pointing back to confinement being an issue, whilst the project has moved on. Why?

Confinement of energy? Confinement of magnetic field? Confinement of electrons? It could mean anything (but confinement of a thermal plasma?).

I take it as wiffleball proven. Current step, scaling laws, as noted. Without wiffleball, why test scaling?
Obviously, you may take it as you wish.

[chrismb]

You keep pointing back to confinement being an issue, whilst the project has moved on. Why?

Confinement of energy? Confinement of magnetic field? Confinement of electrons? It could mean anything (but confinement of a thermal plasma?).

I take it as wiffleball proven. Current step, scaling laws, as noted. Without wiffleball, why test scaling?
Obviously, you may take it as you wish.

I'll take it any way the published data takes it. Which is...?

How's the FoI appeal going?

[ladajo]

I am giving them breathing room until April.
I personally expect that WB8.1 funding paper will fly in Feb/Mar if WB8 performs as expected. They should be hot now and running.
(Someone needs to check the power meter out back weekly )
If we see WB8.1 $$, then that means DD scales well, and pB&J has a shot.
I think that folks are still maneuvering for project and follow on control based on impending WB8 results.
The project is still held to a very small circle of folks.

[happyjack27]

I take it as wiffleball proven. Current step, scaling laws, as noted. Without wiffleball, why test scaling?
Obviously, you may take it as you wish.

another thing that concerns me is continuous operation. there are many reasons why the power gain may be much worse than pulsed operation. e.g. the word that inspires fear in the hearts of plasma physicists everywhere: "thermalization". (ahhh!!)

[icarus]

Rick has publicly stated that confinement is proven.

Henry Paulson, then treasury secretary of the USA publicly stated that the financial crisis was contained after the credit markets froze up on Aug. 7th 2007.

Even very, very important people can be misleading in their public statements, intentionally or otherwise.

[D Tibbets]

........

Rick can point out anything he likes in comparison with ITER, but to little effect because Polywell will NOT function as a thermalised machine. Magnetic bottles with cusps has been tried and tried again and it has not been made to work with two cusps, so how will it work with a dozen or more! Polywell has a point to make to prove out, one way or the other, electrostatic confinement of ions by magnetically confined electrons, and we wait [and wait and wait] to see some outcome on that. But to talk of it as a thermal-plasma confining machine is just a bit silly.

Yes, Coulomb collisions can lose energy. Bremsstrulung interactions/ collisions is a dominant form of this, especially, with high Z fuels. Ion, ion Coulomb collisions also, certainly lose energy, but from my limited exposure, this seems to be a small concern in a fusion capable plasma relative to Bremsstrulung. And, bremsstrulung losses have been addressed (thought you might argue that it has not been successfully addressesd).

I think Nebel did not imply a Polywell could operate sucessfully with a fully thermalized plasma. What he did say was that the transverse, or angular momentum of the plasma could be thermalized ( little or no central focus), but the radial component of thermalization needs to be significantly impeded for the system to work, again edge annealing enters the picture.

And, if Coulomb collision energy losses are intolerable in a Polywell, they would be just as intolerable in any other type of fusion plasma. Density dependent time scales would change, with there corresponding volume and confinement time implications, but the energy losses per collision would not. Except- the Polywell has higher fusion to Coulomb collision ratios because of the claimed narrower energy distribution. The Maxwellian plasmas of a Tokamak have a lot of ions not contributing to fusion, but contributing to coulomb collision losses. I think this is why the Maxwellianized plasma machine can only have positive Q's with D-T fuel. Even if you could push the average temperature high enough, the losses from non fusion collisions would always be too much with out that ~ 100 fold advantage that D-T fusion has (at appropiate portions of the fusion crossection curve).

[EDIT] Perhaps instead of speaking of transverse thermalization, I would do better to state that the vectors of the ions could become nearly random so that there would be little or no central convergence. But the velocity component of the ions needs to be kept within some less than Maxwellian limit.

Dan Tibbets

[Enginerd]

You keep pointing back to confinement being an issue, whilst the project has moved on. Why?

Confinement of energy? Confinement of magnetic field? Confinement of electrons? It could mean anything (but confinement of a thermal plasma?).

Confinement of all data and all test results of course. I'll gladly grant that has indeed been proven.

[ladajo]

[TallDave]

Each time ions don't fuse when they meet (which is 3-sigma statistically all the time!), they loose energy.

Sure, but that energy doesn't vanish, it gets passed to one or the other ion. Since the ions don't get lost to upscatter to any significant degree, there's nowhere for the energy to go (except to the electrons, which can upscatter to the wall, but tend to give up all their energy doing so -- Joel's latest simulation suggests this process is very efficient and in fact satisfies Rider's requirement in that respect).

Rick can point out anything he likes in comparison with ITER, but to little effect because Polywell will NOT function as a thermalised machine.

Not as a fully thermalized machine, no, but Chacon et al did the full bounce-averaged Fokker-Planck simulation and it says large Q values are possible with partial thermalization.

Rick has publicly stated that confinement is proven.

At the WB-6/7 scale, I should hasten to add. Rick has also noted, with admirable intellectual honesty, that transport scaling is where new fusion schemes have typically stumbled. I won't be surprised if B scaling doesn't look enough like the B^.25 Bussard claimed for PW to be economically viable. (Disappointed, but not surprised.)

[ladajo]

And thus the desire to see hard data from WB7 and compare to WB8. WB8 numbers will rewrite some of the predictions to be sure. As you stated, how much is the key.
The other truth of science will play as always, something not expected will be seen, or has been seen at this point.

4 months.

[D Tibbets]

Sure, but that energy doesn't vanish, it gets passed to one or the other ion. Since the ions don't get lost to upscatter to any significant degree, there's nowhere for the energy to go (except to the electrons, which can upscatter to the wall, but tend to give up all their energy doing so -- Joel's latest simulation suggests this process is very efficient and in fact satisfies Rider's requirement in that respect). ....

Actually, radiant energy is lost- the best example is Bremsstrulung X- rays. Bussard considered this in one of his early papers. He shows a table of different fuels and the minimum temperature that needs to be obtained for the fusion to catch up to these losses (I believe radiant losses), even with perfect confinement. D-T was ~ 5 Kev, D-He3 and P-B11 were higher. For some reason D-D was not listed, though I'm guessing it would be somewhere in the neighborhood of 8-10 KeV. Also, I don't know if these numbers take into account the ~ 25-30% energy recovery that could be obtained with a thermal cycle. Borrowing Eric Learners direct X-ray conversion scheme might increase this recovery to ~ 80%. If it works, that in itself may be a game changer for some fusion schemes.

Dan Tibbets