New here – My FF questions

[theanphibian]

I have done a great deal of reading into energy research and my general area is fission. I’ve consumed much of the information on Focus Fusion and wish to offer my congratulations on what seems to be a continuous string of developments.

The merit of a project should come from the expected probability of success times the expected benefits of success. I concur with the views expressed on this site that Focus Fusion with pB fusion would achieve the holy grail of energy sources. In fact, I feel that I can’t express this opinion strongly enough. But words really don’t suffice for this. Even if a highly altered and significantly more expensive version of the Focus Fusion design succeed, then the world would be set on a completely different track. I enjoy speculating about futuristic matters, but reasonable skepticism dictates the extravagance of the vision should probably be correlated with a lower probability of success.

Nonetheless, I take Focus Fusion to have a significant amount of credibility. I reserve a great amount of hope that Z-pinch may be the breakthrough we’re all looking for. I understand that Sandia is also making some heavyweight claims about their results. And it would seem that their project and Focus Fusion have a great deal in common. Funding seems to be flowing at a similar level for both, and both aim for a major breakthrough that could ultimately produce power. I understand the criticism that the Sandia approach uses filament wires, limiting the ultimate potential of the machine, but I’ve seen discussion of full-scale power plants that appear quite plausible while still using the idea of expendable wires. Notably:

heavy element wires -> z-pinch -> massive x-ray flux -> inertial confinement -> fusion

I’m not strongly interested in the mechanics of a power plant. I believe that if sufficient fusion conditions could be demonstrated, then billions in funding will be peanuts. We’ll find some way to make power out of it. Humans are good at that. Likewise for FF.

I’ll get to the point.

What is this picture technically?
Plasmoid X-Ray Image
(you’ll just have to click it because I can’t get it to post images)

Is it an x-ray image of the bremsstrahlung from the plasmoid? How big is the plasmoid again? My intuition is that it is very very small (b/c it induces fusion) to the point that you wouldn’t be able to image it. Maybe it’s a premature plasmoid? I don’t know. But it seems clear that the radiation is what’s directly emitted from the plasmoid. Is this correct? And why are there so many apparent filaments at the top and bottom? Isn’t the number of filaments equal to the number of outer Copper electrodes? Perhaps the image appears this way because it’s spinning significantly during the time of exposure.

How on Earth do the charges separate?

Again, I think I’m relatively informed on this technology, but I lack a fundamental understanding of how you plan to achieve the charged particle beam that supposedly would lead to direct energy conversion.

pB fusion produces 3 He nuclei – yes. Those will have a relatively random angular distribution. I don’t expect it to be isotropic, but no matter what kind of initial velocity vectors you have for the Boron and proton, they products will come out in some mostly random direction. Why do we expect a charged particle beam to escape from the top and bottom (for lack of better terminology) of the plasmoid?

Beams Shooting out of Plasmoid

My imagination leads me to speculate that it is believed that charges will fly out the ends because the electromagnetic confinement of the fusioning volume has less pressure in the Up-Down directions – in other words, is largely a cylindrical pressure. This operates on the assumption that the plasmoid can, in fact, contain the He ions within the volume. Understandably, if the fission products are contained, then the ball just heats up until the fuel is used up (assuming confinement is held).

Are you Doing a Lecture Circuit?

I have yet to hear anyone speak about z-pinch possibilities in person. But I know it’s an established topic with an active research community.

Eric Lerner’s talk at Google made a big impression with a lot of people (including myself). I am curious if anyone is actively going around and giving seminar presentations. Or are you planning any milestone publications in the near future? Is there any interest in doing university department seminars? In addition to Nuclear Engineering, I think that sustainability advocates should have some interest.

[Aeronaut]

Glad to have you with us, theanphibian.

A simplified view of the DPF is the Lee model, developed by professor Sing Lee of the UN University. http://www.nsse.nie.edu.sg/research/plasmaphysics/ComputationPkg.htm will get you the Mather style DPF simulator and all of the math behind the simulator, which includes the physics. This model divides each machine cycle into 5 phases, the Axial, Radial inward shock, Reflected radial shock, compressive/radiative, and expansion. As the names imply, the last 4 phases use a cylindrical model.

My understanding of the purple image is that its the filaments beginning to kink up near the beginning of Phase 2. I still don’t have a direct correlation between much of the Lee model (simplified but easier to grasp initially) and the LPP model, which is very detailed. But there are 2 simulators being tested. Maybe FF will have a package similar to the Lee model this year.

The compressing cylinder is the collapsing magnetic field, which can exceed 10GG, heating the plasmoid containing the fuel for any shot by compressing it into a near solid. The plasmoid diameter for the energy yield charts is 8.6 microns. As the plasmoid is compressed, some fusion begins, producing positively charged helium ions and the resulting free electrons. The magnetic field provides the motion and the tight focus of the beams.

Even though it needs to be shown as a beam for that concept, the electron beam is actually busy heating the plasma even hotter. Something like thermal runaway in an overheating transistor. This is where the majority of the fusion reactions begin occurring.

I’d love to give presentations on the FF in the Great Lakes region, but PM me if you can provide a venue in other regions and we may be able to swing at least a tele-conference. I’m currently working up a plan to clone the FF-1 at over 2,000 universities and colleges to pull a time warp on public awareness, time to peer-review, time to market, etc. I just posted the rough outline on our facebook wall, if you’d like to comment.

I think it was Napolean Hill in Think and Grow Rich, that thoughts draw others of their type.

[Breakable]

I tend to think that the magnetic field created by Plasmoid makes particles with different ionization move in opposite directions.
The effect is described here

[theanphibian]

Aeronaut wrote: Glad to have you with us, theanphibian.

A simplified view of the DPF is the Lee model, developed by professor Sing Lee of the UN University. http://www.nsse.nie.edu.sg/research/plasmaphysics/ComputationPkg.htm will get you the Mather style DPF simulator and all of the math behind the simulator, which includes the physics. This model divides each machine cycle into 5 phases, the Axial, Radial inward shock, Reflected radial shock, compressive/radiative, and expansion. As the names imply, the last 4 phases use a cylindrical model.

The link you mention defaults to the general research site. The material was removed at some time in the past. I would offer as an alternative:

http://web.archive.org/web/20070216131940/http://www.nsse.nie.edu.sg/research/plasmaphysics/ComputationPkg.htm

This page does offer some novel content, thanks for the leads. The page has some Excel books that can be downloaded with a simulation based in Visual Basic, but it doesn’t work on my computer, oh well. Anyway, I’m not strongly interested in the computational specifics right now, I’m mostly interested in the qualitative physics since I still haven’t fully grasped those yet.

My understanding of the purple image is that its the filaments beginning to kink up near the beginning of Phase 2. I still don’t have a direct correlation between much of the Lee model (simplified but easier to grasp initially) and the LPP model, which is very detailed. But there are 2 simulators being tested. Maybe FF will have a package similar to the Lee model this year.

I understand those are the filaments, that makes sense.

Am I correct in taking that the purple image is from imaging from a real experimental test? Not computational or anything of the sort. But I know the modeling is very important (otherwise you’re wandering around in a 6-dimensional space I hear).

The compressing cylinder is the collapsing magnetic field, which can exceed 10GG, heating the plasmoid containing the fuel for any shot by compressing it into a near solid. The plasmoid diameter for the energy yield charts is 8.6 microns. As the plasmoid is compressed, some fusion begins, producing positively charged helium ions and the resulting free electrons. The magnetic field provides the motion and the tight focus of the beams.

Even though it needs to be shown as a beam for that concept, the electron beam is actually busy heating the plasma even hotter. Something like thermal runaway in an overheating transistor. This is where the majority of the fusion reactions begin occurring.

I was previously looking at the actual pB reaction as a 2-to-3 body problem. But we are mostly interested in the dynamics of a He (as the reaction product) gas within the plasmoid confinement. So at 10 GG we will see a huge effect from that. Also, since it’s so dense, the coulomb interactions between ions will be abundant… I’m just thinking out loud here, I’ll keep reading up. I believe it’s completely possible for the beams to happen but it seems odd that one would be positively charged and the other negatively charged. I could see it happening, but I’m vague on the specifics.

[jamesr]

theanphibian wrote:
Am I correct in taking that the purple image is from imaging from a real experimental test?

I believe the image is taken from Bostick, Nardi et al 1976 paper:
RADIATION DAMAGE (BLISTERING) IN Al, Cu, Si BY EXPOSURE TO A PLASMA FOCUS DISCHARGE doi:10.1016/0022-3115(76)90350-0

The caption to the image in the paper is:

(c) Image converter photograph of current sheath (5 ns exposure by visible light) 20-30 ns before maximum axial compression,
as sheath collapses toward the “pinch” stage. The plasma vortex filaments which are visible on the current sheath provide the “raw material” out of which the plasma
nodule will be probably formed. Maximum voltage applied to the electrodes: 15 kV: local current within the nodule can be much larger than peak current on electrodes
because of current loops formation in the plasma. Plasma nodules are strong sources of bremsstralung X-rays and can be observed by pinhole camera photographs.
In one discharge the emission intensity from one nodule is usually higher than intensity of other nodules when a multiple-nodule structure is formed in the
plasma within the axial column as it is outlined in (a).

[Henning]

Yes, that image is an actual image of a sheath. Rezwan explained it in some old article. Actually it’s black and white, only for aesthetic reasons it was coloured. See also the Wikipedia picture here: http://en.wiki.org/wiki/File:DPFfig2_.jpg

[KeithPickering]

theanphibian wrote: And why are there so many apparent filaments at the top and bottom? Isn’t the number of filaments equal to the number of outer Copper electrodes?

The filaments are created in counter-rotating pairs, with one pair per outer cathode. So the number of filaments is 2 x electrodes.

See this image:

https://focusfusion.org/index.php/gallery/image_med/6/

[Aeronaut]

KeithPickering wrote:

And why are there so many apparent filaments at the top and bottom? Isn’t the number of filaments equal to the number of outer Copper electrodes?

The filaments are created in counter-rotating pairs, with one pair per outer cathode. So the number of filaments is 2 x electrodes.

See this image:

https://focusfusion.org/index.php/gallery/image_med/6/

I’ve been misinterpreting the slideshow. Glad the question was raised.

[jamesr]

Its not quite as simple as that. There may be many filaments, and each one could be comprised of lots of micro-filaments. Plasma is an unstable thing. Density & temperature gradients will tend to cause instabilities which will cause splits and reconnections of the filaments and turbulent behaviour.

[Aeronaut]

jamesr wrote: Its not quite as simple as that. There may be many filaments, and each one could be comprised of lots of micro-filaments. Plasma is an unstable thing. Density & temperature gradients will tend to cause instabilities which will cause splits and reconnections of the filaments and turbulent behaviour.

That leads to another question or few.

1. How does the plasma sheath rotate during the axial runout phase? This would seem to imply huge spikes in the current waveform.
2. Would a more correct visualization be that each cathode’s filament system is the base of a corkscrewing spiral?

[Author]

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