Aviation Week on the Lockheed Skunkworks CFR

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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David_Jay
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Location: Grand Rapids, Michigan

Aviation Week on the Lockheed Skunkworks CFR

Postby David_Jay » Wed Oct 15, 2014 12:31 pm

AWST has some significant coverage of the Skunk Works Compact Fusion Reactor (CFR)

Intro article here:
http://aviationweek.com/technology/meet ... actor-team

Additional details in an article here:
http://aviationweek.com/technology/skun ... or-details
not tall, not raving (yet...)

David_Jay
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby David_Jay » Wed Oct 15, 2014 12:41 pm

A video here:

http://aviationweek.com/blog/high-hopes ... -transport

Let me know if any of these links require registration (since I am registered I can't see what does/doesn't require registration), I can probably cut-and-paste the text from the two articles.
not tall, not raving (yet...)

crowberry
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby crowberry » Wed Oct 15, 2014 1:47 pm

Thanks David_Jay for this very interesting news! :D The articles and the video are accessible without a password. At last there is some concrete information about the Lockheed Martin reactor:

Overall, McGuire says the Lockheed design “takes the good parts of a lot of designs.” It includes the high beta configuration, the use of magnetic field lines arranged into linear ring “cusps” to confine the plasma and “the engineering simplicity of an axisymmetric mirror,” he says. The “axisymmetric mirror” is created by positioning zones of high magnetic field near each end of the vessel so that they reflect a significant fraction of plasma particles escaping along the axis of the CFR. “We also have a recirculation that is very similar to a Polywell concept,” he adds, referring to another promising avenue of fusion power research.


Image

So it seems they are using electric fields for the recirculation and to manage the losses like in a Polywell. And the ends they try to plug with stronger fields.

Maybe they have some patents submitted as they come out with this information? LM for sure has more resources than EMC2 to progress on a fast pace.

mvanwink5
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby mvanwink5 » Wed Oct 15, 2014 3:36 pm

I like the cables used to hold the toroidal magnets. I am sure these guys appreciate EMC2 and J Park's paper on cusp plugging. "Pop the clutch" may have been the breakthrough needed. Anyway, looks like I was rash to count LM out of the Dark Horse race.

It's a funding scramble now as much as it is a matter of science. LM has a really polished sales pitch, especially on development time to prototype.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

swamijake
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby swamijake » Wed Oct 15, 2014 4:36 pm

Isn't that just a magnetic mirror? I don't get it.

Skipjack
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby Skipjack » Wed Oct 15, 2014 4:50 pm

Seems like they borrowed a lot from others. The neutral beam injection reminds me of what Tri Alpha is doing.
What I don't understand is, if they can achieve a high beta, why cant they burn advanced fuels?

DeltaV
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby DeltaV » Wed Oct 15, 2014 5:41 pm

I count 5 coils. Numbering 1-5 as nearest-farthest, coil 3 (center coil) appears to have the largest diameter.

Ignoring the two end coils, this looks like an "inverse" of Torulf's "synthetic" FRC:
Image
Attachments
Lockheed_CompactFusionReactor_5Coils.png
Lockheed_CompactFusionReactor_5Coils.png (123.92 KiB) Viewed 15877 times

birchoff
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby birchoff » Wed Oct 15, 2014 5:49 pm

Since they have a blanket given the image below. That must mean they are planning on burning neutronic fuels like DD or DT. Which begs the question, wouldnt those superconducting rings be operating in a very extreme neutronic environment. Which would mean they should be gin degrading pretty quickly over time. Though a simple solution given arrangement would be to move the magnetic rings to be outside the blanket instead of inside the blanket.

Image

AcesHigh
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby AcesHigh » Wed Oct 15, 2014 5:59 pm

the answer to your question must be here... if you can make sense of it... words in an article rarely explain things that well.

" Instead of constraining the plasma within tubular rings, a series of superconducting coils will generate a new magnetic-field geometry in which the plasma is held within the broader confines of the entire reaction chamber. Superconducting magnets within the coils will generate a magnetic field around the outer border of the chamber. “So for us, instead of a bike tire expanding into air, we have something more like a tube that expands into an ever-stronger wall,” McGuire says. The system is therefore regulated by a self-tuning feedback mechanism, whereby the farther out the plasma goes, the stronger the magnetic field pushes back to contain it. The CFR is expected to have a beta limit ratio of one. “We should be able to go to 100% or beyond,” he adds."

" one of the reasons we think our physics will work is that we’ve been able to make an inherently stable configuration.” One of the main reasons for this stability is the positioning of the superconductor coils and shape of the magnetic field lines. “In our case, it is always in balance. So if you have less pressure, the plasma will be smaller and will always sit in this magnetic well,” he notes."

birchoff
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby birchoff » Wed Oct 15, 2014 6:17 pm

AcesHigh wrote:the answer to your question must be here... if you can make sense of it... words in an article rarely explain things that well.

" Instead of constraining the plasma within tubular rings, a series of superconducting coils will generate a new magnetic-field geometry in which the plasma is held within the broader confines of the entire reaction chamber. Superconducting magnets within the coils will generate a magnetic field around the outer border of the chamber. “So for us, instead of a bike tire expanding into air, we have something more like a tube that expands into an ever-stronger wall,” McGuire says. The system is therefore regulated by a self-tuning feedback mechanism, whereby the farther out the plasma goes, the stronger the magnetic field pushes back to contain it. The CFR is expected to have a beta limit ratio of one. “We should be able to go to 100% or beyond,” he adds."

" one of the reasons we think our physics will work is that we’ve been able to make an inherently stable configuration.” One of the main reasons for this stability is the positioning of the superconductor coils and shape of the magnetic field lines. “In our case, it is always in balance. So if you have less pressure, the plasma will be smaller and will always sit in this magnetic well,” he notes."


Still doesnt answer my question I believe. It sounds like they are saying they basically have two sets of magnetic field generators. The rings inside the chamber and those blue tubes on the outside of the blanket. Where the goal is to create this magnetic field gradient where the farther away from the center the plasma goes the steeper the magnetic field gradient becomes.

That is all good. But if your burning DD or DT some constant rate of neutrons being generated will hit the Ring inside the chamber that houses the super conducting magnet. Since neutrons do not interact with magnetic fields then they will eventually embrittle the ring housing and damage the superconducting material that makes up the electro magnet in the ring which would inevitably lead to quenching as I understand it. This is not necessarily an insurmountable problem, but it would be nice if they explained how they were going to deal with that problem. Again assuming they plan on burning DD or DT. Like Mcguire said, they took the ideas of a bunch of reactors and mixed them together to see if they could make something work. Which could also mean they plan on buring 3He or pB11. In which case the neutron problem pretty much goes away, or at least is reduced to the point were having to simply refurb the reactor over some economically viable period of time is not that big a deal.

KitemanSA
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby KitemanSA » Wed Oct 15, 2014 6:26 pm

One article I scanned suggested that this was a flow thru magnetically guided electrostatically confined system. ICBW.

Ivy Matt
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby Ivy Matt » Wed Oct 15, 2014 6:40 pm

There's also a Reuters press release masking the rounds:

http://newsdaily.com/2014/10/lockheed-s ... y-project/

[Lockheed] said future reactors could use a different fuel and eliminate radioactive waste completely.
Temperature, density, confinement time: pick any two.

D Tibbets
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby D Tibbets » Wed Oct 15, 2014 6:41 pm

swamijake wrote:Isn't that just a magnetic mirror? I don't get it.


At firs,t the image did remind me of that- with end cap magnets to decrease axial plasma losses. The selinoid with end caps has been described in the past. The major difference is the central focus issue and the B fields that are not always convex towards the plasma.

But looking closer, the central three magnets do look like what I have described as a Polywell derivative. The second and forth magnets are the equivalent of an old mirror machine with an aspect ratio of ~ 1 (width equals separation). But the central (3rd magnet) placed between splits the single intolerable leakage equatorial line cusp into two much more narrow line cusps. This substantially reduces and possibly greatly reduces the total line cusp losses. The Polywell does the same thing with a different geometry. The line cusp losses are greatly reduced with the important preservation of the internal reaction volume. You could also decrease the equatorial line cusp loss in a mirror machine by moving the magnets closer together, but this also shrinks the corresponding internal reaction volume.

Also, this setup allows for a central focus like the Polywell, along with the favorable convex field lines towards the plasma, and open spaces between the magnets that allows for electron recirculation. The truncated cube Polywell has two line cusps that are deformed and compressed to the extent that referring to them as corner point like cusps has been used. It also has 6 face centered point cusps. This design has the two line cusps that are compressed but not deformed and two point cusps. The line cusps may average greater width than the Polywell, but the reduced number of point cusps may make up for most of this. Also, the reaction volume is less spherical, but still quasi-spherical as I understand it.

I have been considering this three ring arrangement for ~ 3 years and have done some permanent magnet experiments in this configuration. This has given me insight into the gross magnitude of line cusp narrowing possible without the critical shrinking of the internal volume. I think the central magnet having a greater diameter is beneficial for several reasons. One key to appreciating the design is to remember that the magnets have real dimensions . Bussard, etel made the mistake of assigning mathematical lines to the magnets which changed ExB diffusion perspective and also the effective separation of the magnets. With mathematical lines the separation is straight forward. But, with different minor radius dimensions assigned to the magnets things change. All that is important is the strength of the B field at the surface of the magnet cans. as this changes the effective separation of the magnets for cusp descriptive purposes. EG: two magnets with a separation of 1 meter as measured from the center of each magnet minor radius (can radius). If the cans are 10 cm in minor radius, the seperation is only 80 cm from can surface to can surface. This surface is where the B field starts falling off in the essentially vacuum medium. The internal can fields are irrelevant from this perspective. Therefor the advantage of having a central ring magnet is greater than simple mathematical calculations with assumed linear magnet dimensions would suggest. Having the thicker center magnet magnifies this if circular dimensions are assumed. Having elongated oval shape along the cylinder axis of the machine would help more. How much deviation from circular can be tolerated is an open question. Thus the greater minor diameter of the central magnet and resutant greater major radius. Also, having the central magnet greater in diameter changes the geometry of the two line cusps. Instead of pointing out laterally, they are canted towards the ends. This may allow for a smaller diameter vacuum vessel and have advantages for placement of conversion grids, plasma out flow guiding grids (think rocket thrust), etc.


The two end magnets are somewhat confounding as they do not contribute to a central focus, but perhaps their contribution to restricting/ controlling the point cusp losses are advantageous.

The greatest distinction between this and the Polywell design may be how the issue of electron/ plasma injection through the available cusps is handled.

The comment about operating past Beta =1 is confusing. With cusps, the best confinement is at Beta=1, or infinitely close to it. Past Beta=1 or Beta>1, the cusp losses increase. I speculate that other issues may compensate for this though. The "Wiffleball" surface may be even more 'sharp'. And the total reaction volume may be a little larger, so operating slightly past Beta= 1 may be the optimal compromise. Recirculation and electron injection issues may also contribute to the best knob setting...

The D-T choice of fuel seems pessimistic, but perhaps this conservative approach (like Dr Parks comments for the Polywell) are the best political position as the Fusion community has a familiarity and acceptance of this approach.

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

tokamac
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby tokamac » Wed Oct 15, 2014 6:44 pm

DeltaV wrote:I count 5 coils. Numbering 1-5 as nearest-farthest, coil 3 (center coil) appears to have the largest diameter.

Ignoring the two end coils, this looks like an "inverse" of Torulf's "synthetic" FRC


Indeed.

Image

From http://newsdaily.com/2014/10/lockheed-s ... y-project/

D Tibbets
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby D Tibbets » Wed Oct 15, 2014 6:57 pm

Note that the other picture/ illistration showing only two magnets is confusing. Either it would be a simple mirror or a short selinoid, The first has intolerable line cusp losses and the second has unfavorable B field geometry for macro instabilities. For illustrating a lithium blanket it is OK. Until otherwise indicated I chose to discount it.

I suppose a two magnet mirror machine might perform better if you could pump in plasma fast enough to push the machine to near Beta = one conditions. But the intensity and thus the cost of injecting the plasma/ electrons is perhaps 10 times greater, so it is much more difficult, except that electron injection efficiency may actually be better. The Q would suffer. That would probably necessitate the D-T reaction with its fusion cross section advantages and power yield advantages. In that regard the illistration may actually represent a potential viable approach. The Beta= one consideration trumps the baseline cusp loss picture.

Dr Parks, etel at EMC2 presentation of strong Wiffleball- Beta =1 (close) may be the game changer.

The race is on to achieve major funding for this general approach. Tokamakians beware... :twisted:

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


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