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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mvanwink5
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby mvanwink5 » Sun Oct 19, 2014 5:59 am

Perhaps having the internal coils and supports at the same potential as the wall helps. Also, having the attachments at the coil edge would seem to be better than where the nubs in WB-7 were located. So, perhaps the supports aren't a show stopper. This Fusion business is just full of tricks, and I think a fusion rabbit's foot needs to be included in the patent. Perhaps if we look closely at the LM pictures, hidden in the reactor design is a horse shoe, 4 leaf clover, and a rosary.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

TheRadicalModerate
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby TheRadicalModerate » Sun Oct 19, 2014 7:06 pm

Skipjack wrote:A steady state reactor wont be able to do Tritium suppressed and He3 boosted D+D though, unlike Helion's pulsed reactor, which can do just that.
So they would have to go all the way to PB11, which is a lot more challenging.


I'm having a hard time imagining how you'd get charged fusion products out of this thing in a coherent enough form to harvest more than thermal energy from them. In a polywell, the magnetic fields are trivial compared to the fusion product energy. Here, the B-fields are at least going to do some funny things to the exit trajectories. That makes direct conversion a little... odd, doesn't it?

Skipjack
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby Skipjack » Sun Oct 19, 2014 8:45 pm

TheRadicalModerate wrote:
Skipjack wrote:A steady state reactor wont be able to do Tritium suppressed and He3 boosted D+D though, unlike Helion's pulsed reactor, which can do just that.
So they would have to go all the way to PB11, which is a lot more challenging.


I'm having a hard time imagining how you'd get charged fusion products out of this thing in a coherent enough form to harvest more than thermal energy from them. In a polywell, the magnetic fields are trivial compared to the fusion product energy. Here, the B-fields are at least going to do some funny things to the exit trajectories. That makes direct conversion a little... odd, doesn't it?

Good point!

D Tibbets
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby D Tibbets » Mon Oct 20, 2014 3:15 pm

TheRadicalModerate wrote:
Skipjack wrote:A steady state reactor wont be able to do Tritium suppressed and He3 boosted D+D though, unlike Helion's pulsed reactor, which can do just that.
So they would have to go all the way to PB11, which is a lot more challenging.


I'm having a hard time imagining how you'd get charged fusion products out of this thing in a coherent enough form to harvest more than thermal energy from them. In a polywell, the magnetic fields are trivial compared to the fusion product energy. Here, the B-fields are at least going to do some funny things to the exit trajectories. That makes direct conversion a little... odd, doesn't it?


I fail to see the difference. The charged fusion products will not be contained by any potential well. They will exit the same as in a Polywell. Provided the B fields strength is sufficient to turn the fusion charged particles internally, they will only exit via a cusp. Just like in the Polywell they will follow a magnet line as they loop around a magnet while in the low Beta exterior region. Because of their KE the loop will be much greater, reaching radii much greater than fuel ions or electrons that have escaped. So long as the cusps are orientated with one end pointed at the machine center and not parallel to it there will be a radii where external grids can selectively pick them off. The situation may be different as you consider addition paired magnet cusp regions in more distal ends of a multiple (more than three) magnet setup. These end regions may have FRCs, so I'm uncertain where the fusion ions would end up. But, I am thinking that these modifications to the basic Polywell central focus fusion concentration setup will be a minor part of the fusion yield. I'm guessing that these additional charged particle manipulations is mostly about conserving the fuel ions , and primarily the electrons, and contribute little to the production of fusion ions. It is more related to increasing the electron/ energy confinement, than the fusion yield. The triple product is boosted, not because of additional fusion, but because of improved confinement.

Of course this has all sort of considerations. The mono energetic electron energy may be more problematic, Bremsstruhlung considerations may be different , etc. The central region (inside the large central magnet) is presumed to produce the most fusion due to the assumed significant confluence/ central focus possible here. Also, I am assuming that the end regions are fed only with escaped electrons from the central core. Using Polywell considerations (Wiffleball effect) the average densities obtainable may be greatest in ths central core region.

And, of course, this speculation is mostly moot if D-T fuel is the only option. That is what is mentioned as the fuel for this design, and the predominance of the fusion output energy as neutrons dictates only heating as the dominate energy harvesting method. Only D-He3 , P-B11 or even more difficult fuels may lend themselves to worthwhile direct conversion efforts.

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

DeltaV
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby DeltaV » Tue Oct 21, 2014 4:47 pm

Beginner's luck...
On my second day on this forum, I managed to inspire Lockheed to develop me a fusion reactor.

http://www.talk-polywell.org/bb/viewtopic.php?f=3&t=1537

This is about some nice geometrical properties of spheroids which may, or may not, have application to offshoots of the baseline Polywell concept. I don't know enough plasma physics to do more than speculate, but I can always hope that some physicist might get inspired...
Forcing a static, non-spherical field would probably be a bad idea (as Dr. Bussard said, naturally occurring fusion reactors are all spherical), but might there be some advantage in modifying the Periodically Oscillating Plasma Sphere (POPS) concept to cause field shape to oscillate between spherical and prolate spheroidal, spherical and oblate spheroidal, or oblate and prolate spheroidal? I only have a cursory understanding of POPS, so I'm also assuming here that it normally tries to keep things as spherical as possible. Would there be any tendency for particles in a spheroidal field to concentrate near the focal line or disk? In Slough's concept, FRCs are linearly translated into collision. IF Polywell particles did tend to concentrate near spheroid focal regions, could they be slammed together by driving the prolate foci, or the oblate focal circle, into a central point?

I had a gig there once, so they already have my SSN for royalty direct-deposit.
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D Tibbets
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby D Tibbets » Tue Oct 21, 2014 7:36 pm

Further ruminations comparing the Lockheed design and the Polywell.
[You might want to get a cup of coffee before starting. 8)

viewtopic.php?f=10&t=4629&start=15

Torulf2, I'm not sure what you are saying, the line cusp in the picture is obvious. The two magnets shown are opposing. It is not a solenoid arrangement. The solenoid arrangements are generally accepted as hopeless, due to poor magnetic curvature surfaces leading to macro instabilities.

In the picture 1/2 of a ring magnet is seen on the right, and a full ring magnet on the left. The plasma shows a point cusp with plasma exiting to the left, and a line cusp between the magnets with the plasma exiting in a line or cone between the magnets. If the magnets were the same diameter, this would be a classic biconic opposed magnet mirror machine. In the picture the right magnet would also have a point cusp exiting to the right. What is not shown (in my opinion) is a third magnet located further right. This would result in a picture mirroring what is seen. Copy the picture, flip it horizontally, and paste it on the right side of the original picture. Now you can see the two line cusps along with the two end point cusps. If the central magnet is removed, it would have one equatorial line cusp- the classic mirror machine. By having the central magnet the single equatorial line cusp is split into two, but importantly the width of these two line cusps are now much narrower,and the net result is better containment. If you assume magnets of very narrow width(horizontal width in the picture) or mathematical lines representing the magnets much like Bussard used in his modeling until WB6) the gain would be modest, perhaps halving the net losses from the line cusp component relative to a two magnet mirror machine. But with real magnets with real significant width/ thickness, the relevant magnetic fields are measured from the can surface, not the center line of the magnet. As such the gains from splitting the equatorial line cusp results in significantly greater gains in the confinement efficiency of the line cusp. The fatter the central magnet the better, within some practical limit. For example an oval instead of a circular magnet cross section. For other reasons increasing the diameter of the central magnet may also have benefits. Primarily by increasing the internal volume and by changing the direction/ angle of the two line cusps. This may have benefits in direct conversion grid layout outside the magrid, along with external direction guiding of the escaping plasma- such as for a rocket engine or transformer like energy conversion if the machine is pulsed. Also, having smaller diameter end magnets help to push the B fields to a common focus between the central magnet.

In the Polywell there are at least 6 point face cusps, and these may dominate the losses. In this design there are only two point cusps, so there may be significant gains. The line cusps are very similar to the truncated cube polyhedral shape for the Polywell. There are two end magnets with a central magnet. The difference is that in the Polywell this central magnet is actually a complex assembly of four separate magnets, but still the result is the splitting of a single wide equatorial line cusp into two much narrower line cusps. In the Polywell the resultant line cusps are spiky, but otherwise the same concept.

Consider a 2 dimensional representation of a 3 D object., much like a globe of the Earth. Lay out the two end magnets withe the central magnets laid out side by side- 4 long. Now assign line cusps to the end magnets- it is circular with spikes towards the intersections of the central magnets. Because the central magnets are close to the end magnets at the intercepts, the line cusps look almost like 4 separate point corner cusps, but they are still obviously line cusps. This picture may reveal the similarity of the two designs.

The end result is similar, the magnetic fields still converge to a central minimum/ focus. Any line drawn through the center is still symmetrical. The line cusp (corner cusps in the Polywell) losses could be made similar . And the face point cusps are reduced from 6 to two. I'm not sure if full volume could be maintained with the three ring design compared to the Polyhedral design ,but it would be close, especially relative to the net cusp losses. The magnetic fields remain symmetrical. A line drawn through the center will always be symmetrical. I think Wiffleball inflation is still valid. The internal volume is similar, so plasma volume and trapping is similar.
That is the problem with the two magnet opposing magnet mirror machine. The magnets could be moved very close together to minimize the line cusp losses, but this results in the internal volume also shrinking proportionately. That is the whole point of the Polywell- avoiding the volume shrinkage that occurs with line cusp loss minimization in a mirror machine.

Your mention of the plasma recirculating through the center along field lines could occur, but as it has been hashed out on this forum, and stated clearly in the patent application, this is intolerable. Due to up scattering the electrons and boosting their energy with each cycle, the electron temperature would be out of control and criticisms by Dr A. Carlson would apply- that is- extremely high internal electron potentials would be required to keep losses in check. Once the electron escapes outside the space between the magnets, if it is to be recirculated, it must first stop (be decelerated), and re enter through the same cusp. That way the electron energy upon reentry remains constant. Failing to stop the electron (up scattered) requires that the electron needs to be removed from the system (hit a wall), before it can circle around along a field line and reenter through another cusp.


The extraction from the above thread describes the system in large part in my opinion. Further evolution of my understanding does suggest that circulation (appropriate to call it recirculation hear?) can occur around magnets somewhat like a FRC. If the magnet can surfaces are not charged to high positive voltage the progressive acceleration of electrons that complete an external loop is not a problem. With positive magrids this is intolerable- it would act like a cyclotron particle accelerator, progressively accelerating the cusp exiting electrons that were internally (or externally) upscattered so that they would not be reversed and accelerated back through the same cusp to the same energy that newly introduced electrons would in the positive charged model of the magrid. With neutral grounded magrids, new electrons would be accelerated by the high extraction voltage local to the electron guns. Subsequently, the ideal situation would be that the KE of the electrons would be preserved inside the machine, and also in those electrons that escaped through a cusp and circulated/ recirculated through a neighboring cusp (looped around) would retain the same energy. Up scattering could still be controlled by picking off the more energetic electrons on the more extended magnetic line loops.

Considering the electrons looping around several or more magnets sets up conditions like a FRC. But there are significant differences to a simple FRC in my understanding. Mostly, these differences are two fold.
First, my understanding of a FRC is that the plasma circulates- the neutral plasma, meaning both the electrons and ions are looping around. In the Polywell and what I like to call this cylindrical Polywell, the electrons are looping around (or reversing after exiting a cusp in the positively charged magrid version). But the ions are primarily contained within one core due to the potential well in a non neutral plasma (excess electrons). The FRC aspects are applicable only to the electrons. In a way it is two seperate machines, depending on weather you are talking about electrons or positively charged ions. Cusp escaped ions could indeed circulate around the magnets, but if the potential well is working, this will be a small contribution to the overall ion containment.

Secondly, is the density enhancement internally due to primary cusp confinemant and as (greatly) enhanced by Wiffleball effect. This hundred fold to even many thousands fold increase in internal lifetimes and thus density/ pressure leads to the vast majority of fusions occuring in this central core, weather confluence contributes or not. The loops of electrons and possibly some few ions external to the core magnets is trivial for fusion considerations. I think this differentiates the recirculation of electrons from the plasma trapping in a FRC, at least in a simple FRC. Who knows what perturbations Tri Alpha has added to their system., or compression schemes in other pulsed designs.

The external circulating electrons represents conservation of electron input energy only. If the electrons circulate to an area between two end magnets, they may have an opportunity to pass through the point cusp and back into the primary central core. Otherwise, while trapped between the end magnets they may act as a cusp plug, with all of the complications (good and bad) that result- think of WB5 cusp plugging. The space between the end magnets would not (I think) form another Wiffleball because it is only primarily electrons and the Brillion limits may apply. This is especially true with recent revelations of how difficult it is to establish a Wiffleball. As such, the less dense plasma trapped in the end magnet inter spaces would contribute little to the fusion output.

My concept of the three ring machine is that it is a a simple design sharing most characteristics of a Polywell. Adding additional end magnets may have some modest gain in electron energy confinement. Perhaps this is significant if the performance is marginal. The three ring design may be extensible though. One end magnet could serve as the start of another three ring 'core'. This would reduce the number of point cusps (as a loss mechanisms) from 2 to 1 per core (or less with additional cores strung end to end). Each core would have to have it's own plasma and electron injectors, as leakage from an adjacent core would not be able to build up to Wiffleball conditions on it's own (I think). The contribution of the line cusps to the point cusp loss proportions and the effectiveness of looping retention of the electrons that do escape determine if this has any advantages.

There are all sorts of permutations that might be applied. One consideration is that if recirculation through same cusp or neighboring cusp is good enough, eventually collisional processes will come to dominate, both as energy losses (like Bremsstruhlung), Maxwellion thermalization and ExB diffusion. A big advantage that may never change is the macro stability of the system.

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


mvanwink5
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby mvanwink5 » Wed Oct 22, 2014 9:23 am

Very nice downloads, thanks!
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

DeltaV
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby DeltaV » Wed Oct 22, 2014 4:45 pm

New details on compact fusion reveal scale of challenge
22 October 2014
http://www.theengineer.co.uk/news/news-analysis/new-details-on-compact-fusion-reveal-scale-of-challenge/1019393.article#ixzz3GsrDfsrq

McGuire’s reactor traps the plasma using powerful magnetic fields. Unlike a tokamak, which wraps its plasma in a complex series of fields made by three sets of huge magnets outside the reactor vessel, the CFR has two sets, one inside consisting of two rings suspended in the plasma and one outside, circling the circumference of the cylindrical reactor. The internal magnets produce a type of magnetic field known as a diamagnetic cusp, where the magnetic forces change direction rapidly and force the nuclei in the plasma towards the midpoint between the two rings (this is called a magnetic well). The fields from the external magnets squeeze the plasma, forcing it towards the ends of the vessel, while the two magnets at either end produce a very high magnetic field which acts as a mirror, forcing the particles back into the reactor in a process known as ‘recirculation’. ‘Part of what we’re doing is to probe the properties of that and look at our diamagnetic shape and confinement and see if really works at lower temperature, and as we go forward we’ll increase heating and scale it up,’ McGuire said.
Wiffleball-like...

The small volume of the plasma means that less energy is needed to heat it to the point where fusion occurs, McGuire said. In experiments, the team is using microwave emitters to pump energy in to initiate fusion, but for a working reactor he expects to use the technique of neutral beam injection, where very fast uncharged deuterium atoms shed their energy in the plasma; the build-up of heat from fusion will then be sufficient to keep the reaction going. McGuire claims that the team can reach the point known as ignition — where no more heat needs to be added and fusion is self-sustaining — with ‘less than a kilowatt’ of initial heating. ‘The biggest result is that the plasma is stable over a second-long shot, many hundreds of the ion collision frequency. Looking at the plasma with optical diagnostics, it appears very stable with plasma going down into the magnetic wells.’ As nobody has ever created ignition in a fusion reactor, this is a major claim.


Wagers on there being a mini-Polywell in there?
The SkunkWorks team is currently using a spherical reactor to experiment on plasma heating
Image
The writing on the upper flange says "proton <something>"...

crowberry
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby crowberry » Wed Oct 22, 2014 6:13 pm

DeltaV wrote:Wagers on there being a mini-Polywell in there?

The writing on the upper flange says "proton <something>"...


I would guess that the spherical vacuum vessel contains the three central toroidal magnets that create a magnetic well similar to a Polywell. Or it could be an mostly empty chamber just for testing the micro wave heating?

I think the writing says "proton detector".

If they really have a plasma lifetime of one second, then that is really a great step forward.

hanelyp
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby hanelyp » Wed Oct 22, 2014 9:48 pm

Plasma stable over 1 second isn't the same as 1 second confinement time. In the simulations I'm running (OOPIC) of a slightly simplified version of the skunkworks configuration the confinement is amazingly stable, absorbing an order of magnitude more plasma than beta=1 before appearing to blow out. Keep feeding the plasma in at the right rate and indefinite steady state is plausible. But the confinement becomes leaky via cross field diffusion, mostly near the pole cusps, and unless the latest revision I've made fixes it it gets confinement time in microseconds in simulation. For reference, in my setup beta=1 is around 4e19 ions/m^3, proper fusion temperatures for deuterium.
The daylight is uncomfortably bright for eyes so long in the dark.

Solo
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby Solo » Thu Oct 23, 2014 3:20 am

With mechanical supports for the coils, this idea is dead in the water. You cannot get 'recirculation' that way. All the plasma on the field lines that pass outside those 'internal' rings can ExB or grad-B drift around azimuthally until it collides with the stub and is lost. So you basically turn it into a cusp machine, which has shitty confinement. QED.

Suppose you figure a way to levitate those coils, despite the fact that they are extremely unstable, since they oppose the externally-generated field. You still have a superconducting coil inside a plasma with no room for shielding (not if you want a reactor on a semi truck), and more importantly, no divertor, just a limiter most likely. That right there is going to eat your lunch, because it will introduce too many impurities.

Ok, so what if the coil wasn't a coil, what if we put beams in there? Well, you have Tri-Alpha. (This is essentially an FRC with coils.)

So I give this about 0% chance of going anywhere. My question is, what the heck is LM thinking, letting this brash young dude promise fusion in 5 years? I guess all PR is good PR, and if nothing comes of it in five years, it's no big deal to them.

Robthebob
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby Robthebob » Thu Oct 23, 2014 5:43 am

So i got a question for yall.

No one (documented anyways) before EMC2 could get a cusp machine to high beta. So... how did LM know they could? How could they make the claim that they could unless there was proof that they could... did they figure out how to do it (via neutral injection) before EMC2 did it and just didnt publish anything about it? If they just did and didnt publish anything about, that's pretty unethical.
Throwing my life away for this whole Fusion mess.

RERT
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby RERT » Thu Oct 23, 2014 7:48 am

Solo - worth noting that if something has to carry current into the internal coils, it will presumably be via the supports. The radial current will set up a circulating field which will tend to divert the cusp flow around the supports. At least, that is as far as my intuition goes. I can't immediately see how it would work out in 3D in the 'cusp channel'.

choff
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Re: Aviation Week on the Lockheed Skunkworks CFR

Postby choff » Thu Oct 23, 2014 8:09 am

My guess is that while the electrons can circulate outside the coils circumference the ions stay within. There's only two line cusps and two point cusps. One of the point cusps would be where electrons are injected, the other where they leave. So they don't have to worry about wiffleball formation in order to keep electrons from leaving through corners, they can operate at 1KW.
CHoff


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