Lockheed Martin news

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

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crowberry
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Lockheed Martin news

Postby crowberry » Mon Aug 29, 2016 12:32 pm

Tom McGuire presented the Lockheed Martin CFR status at the US-Japan Compact Toroid Workshop 2016, http://www.physics.uci.edu/US-JAPAN-CT2016/proceedings.html. His talk is entitled Overview of the Lockheed Martin Compact Fusion Reactor (CFR) Program.

mvanwink5
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Re: Lockheed Martin news

Postby mvanwink5 » Mon Aug 29, 2016 1:07 pm

Seems still alive and kicking, LM still funding them (still looking for partnering). No timeline, T5 is next. Presentation is dated 2015.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

crowberry
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Re: Lockheed Martin news

Postby crowberry » Mon Aug 29, 2016 1:49 pm

Yes, the subtitle on all pages says (C) 2015, but the creation date of the document says the 19th of August 2016.

crowberry
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Re: Lockheed Martin news

Postby crowberry » Fri Dec 02, 2016 8:52 pm

Lockheed Martin has published a poster from the APS 2016 conference Lockheed Martin Compact Fusion Reactor Concept, Confinement Model and T4B Experiment.

The Lockheed Martin Compact Fusion Reactor (CFR) concept relies on diamagnetic plasma behavior to produce sharp magnetic field boundaries and confine fusion plasma in a magnetically encapsulated, linearring cusp geometry. Simulations show stable inflation to the high beta, sharp boundary state with constant thickness sheaths. Zero dimensional confinement models predict effectiveness of neutral beam heating to produce high electron temperatures in the T4B experiment. Those same models are used to determine feasibility of an operational reactor and determine required magnetic shielding performance for design closure. The T4B experiment will characterize and test plasma sources in the CFR geometry and conduct initial neutral beam heating experiments. The T4B experiment design and diagnostics suite are presented.

mvanwink5
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Re: Lockheed Martin news

Postby mvanwink5 » Fri Dec 02, 2016 10:24 pm

I really like presentation posters as opposed to slide presentations. McGuire seems to have all the technical and nontechnical sales skills for a fusion project and that bodes well going forward (compared to Polywell. GF and TriAlpha are first class and fully funded).

The size of this machine 7m dia. x 18m long is not small for a 200 MW thermal reactor to be called compact, but it is compact compared to the government funded multi $ billion fusion boondoggle Tokamaks and laser projects. It must still be compact enough for LM applications.

So, in my own words, LM is ready to add neutral beam heating to their T4 reactor. No time table is given, no indication that the experiment has been funded. McGuire has based designs on their model built from past experiment results. The project looks well organized to manage risks from unknowns and to nail them down as early as possible. I have had doubts about the survivability of the internal major magnet support stalks, and stalk details are included in this poster, nice.

The big leap in risk reduction will be this next one, T4 part B, plasma heating via neutral beam injection, which is the same for Polywell, heating plus confinement. Also, it seems all dark horse continuous plasma fusion reactors are converging on neutral beams for plasma heating.

Finally, this project seems to be skating on traditional fusion project thin ice funding and support, ready to be put in the historical fusion scrap closet... or not... (Schrodinger's cat) - I base this assessment on project pace, which seems to have slowed, and lack of timetables and stated financial commitment. Could just be budget cycle and Presidential election cycle which was undetermined before (September 2016) and now is a known change, but what will it be?

But it ain't dead. And the project has matured. I can now believe it is possible. (I am such a skeptic :lol: )

All dark horse fusion projects should be risk managed but funded.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

D Tibbets
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Re: Lockheed Martin news

Postby D Tibbets » Sun Dec 11, 2016 8:25 pm

Lockheed's design uses neutral beams for heating, as does almost every other magnetic confinement scheme, and it may also be used in the Polywell. But, I remain entrenched with the idea that the Polywell uses a potential well to heat the ions, and that potential well is established/ maintained by the injection of energetic electron beams. There may need to be supplemental heating by neutral beams or microwaves, but the potential well is primary. It is also essential that this deep potential well be substantial or ion confinement defaults to magnetic interactions and this is anathema to the Polywell, especially as Dr Parks has devalued the idea of recirculation- through the same cusp or neighboring cusps. This fundamental difference between the Polywell and recirculating machines like Lockheed's/ McGuire's design or in a sense FRC designs is significant. Though, after saying this, I admit that I have seen some mention of electrostatic forces/ charge separation being used in Tri Alphas FRC design to aid confinement.

I further admit that I am somewhat confused by what a Neutral beam is. I did some minimal research, but was not enlightened. Is a neutral beam a hot steam of neutral atoms? And, if so, how do they prevent rapid ionization at the required high energies? Is the beam a tight mixture of ions and electrons that holds itself together better than separate beams of each? If so, how is penetration through magnetic fields effected?

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

mvanwink5
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Re: Lockheed Martin news

Postby mvanwink5 » Sun Dec 11, 2016 9:03 pm

I further admit that I am somewhat confused by what a Neutral beam is.

Glad you asked that...

I thought the neutral beam for Polywell was for startup only.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

hanelyp
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Re: Lockheed Martin news

Postby hanelyp » Wed Dec 14, 2016 1:55 am

In rough terms, they produce a neutral beam by accelerating fuel ions, then neutralizing them with electrons to produce uncharged but very fast atoms. The neutral beam passes through the magnetic field as if it wasn't there, then ionizes when it hits particles in the plasma.

With an open field line machine I'd usually expect injection of charged ions and electrons to work. But that might not play so well with a CFR as the field lines that pass through the end cusps continue through the sheath around the outside of the interior magnets, not through the center of the machine where you want to deposit heat and fuel. It would depend on how well the ions can free themselves of the field lines inside.
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happyjack27
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Re: Lockheed Martin news

Postby happyjack27 » Wed Dec 14, 2016 3:02 am

i think i proposed a while back in this forum, using an ion gun accelerated through a negatively charged electron ring, spewing off the electrons which then join the ions. (or vice-versa: a ring of protons towards a collinear electron source, which might help with focusing. ) since the ions have much more mass, presumably you can collimate them much better, and they'll hold that collimation better. as a (mostly) neutral beam, both the electrons and protons make it through the magnetic wiffleball with much more ease. then the higher magnetic fields pulls the electrons off.

i presume this mention of a neutral beam is sort of the same idea - except presumably there's no wiffleball to get inside.

D Tibbets
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Re: Lockheed Martin news

Postby D Tibbets » Wed Dec 14, 2016 5:45 am

I can see ionizing a gas,accelerating the electrons and positive ions (seems some negatively charged ions are needed for the highest energy neutral beams), matching velocities and having a high degree of recombination. What I do not follow, is how neutral beams with a beam density greater than some minimal amount (low current) do not very quickly undergo collisions with very fast reionization. The energies involved is way above the ionization energy of the atoms. Dr Bussard felt that with a relative few free electrons the subsequent ionization of most of a gas was very quick- within a few dozen microseconds, depending of course on the density.

I wonder if it is a game of getting the beam propagated to the desired area very quickly, before it breaks down. The beam at 10 KeV might be traveling at a speed of a few hundred thousand M/S. In 10 microseconds it could travel a few meters. I suppose that may be adequate, again provided the beam density is not too high. That would seem too limit the power you could inject into a plasma, especially if the working density is higher, like in a Polywell. I suppose a bunch of neutral beam injectors could do the job. Considerations about the ionization cross section also plays a role,

I suppose. In Bussard's gas puff, the very slow neutral gas atoms/ molecules are bombarded by high energy electrons , which ionize some of the atoms, and because of a peak cross section at ~ 100 eV, the secondary electrons (most at a speed near 100 eV) create a very rapid secondary ionization cascade. I wonder if this is impeded somewhat if the atoms are traveling well above this velocity energy- perhaps > 10 KeV (to make up for the slower atom / ion speed due to it's larger momentum). This may impede the ionization rate as it is beyond the cross section peak for free electron ionizing collisions. I suppose the relative vectors along with the atom speed applies. If the secondary electron is knocked off at a vector the same as the beam flow, the relative collision speeds would be similar to the case with a cold gas. But, if the secondary electron vector is to the rear side or backwards, the relative speeds would be different. The difference may not be much but if the collisional ionization cross section curve is steep, it might buy some time.


I suppose such hand waving convinces me that producing neutral beams for injecting particles/ energy through a magnetic field can work for a reactor where no more than a few meters of travel distance is needed. Alas, no neutral beam death ray that could be fired at targets kilometers away- unless of course your neutral beam is actually made up of neutrons, where distance would be limited by the lifetime of the free neutrons, or the atmospheric scattering...

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

mvanwink5
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Re: Lockheed Martin news

Postby mvanwink5 » Wed Dec 14, 2016 12:23 pm

Dan,
Have you looked at pictures of the neutral beam injector cans for the Tri Alpha C2U (bottom of page http://trialphaenergy.com )?
It should give you some idea of distances. Those cans are really fat, I wonder if there is some design in a patent that would reveal what is inside?
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

happyjack27
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Re: Lockheed Martin news

Postby happyjack27 » Wed Dec 14, 2016 2:51 pm

the simple phrase "neutral beam" is ambiguous as to whether it's made up of neutrons, or just an ion beam and an electron beam collinear with each other, or whether it matters at all either way - whether it only matters that the net charge is about zero.

i was under the impression that it only mattered that the net charge is zero - that it doesn't matter whether you have neutrons or ions and electrons, or a mix, or going back and forth.

i pictured it a similiar principle to "gas puff", except it was much more precise - it was more like "gas laser".
and also potentially more energy efficient - if you puff a gas out, you're using pressure, which means a lot of those atoms are bouncing against the cylindrical walls of your pipe, transferring their kinetic energy to it, which gets lost as heat. presumably if you use instead electricromagnetic forces to accelerate, you can get a more precise and higher energy "beam" per unit energy lost entropically.

so in sum my thinking was that it was a more efficient and more precise "gas puff".

D Tibbets
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Re: Lockheed Martin news

Postby D Tibbets » Wed Dec 14, 2016 7:10 pm

happyjack27, A colinier beam of free electrons and ions may have a net charge of zero, but there are two obvious (to me) complications. Without the ions and electrons being very tightly coupled (neutral atom) and at the same energy,thus traveling at the same speed, there would be the two stream instability as I understand it. Where the ion goes the electron goes in an atom. In a plasma, the electrons travel ~ 60 times faster than deuterium atoms if at the same kinetic energy, so at the same energy the electrons quickly outpace the ions with a large and rapid buildup of space charge. With separate ion and electron guns matched for velocity, not energy, this charge separation would be minimized, at least till the ions and electrons thermalized with each other- which I understand is a relatively slow process due to the different momentum (the same consideration that governs neutron thermalization in a substrate, low molecular weight atoms are much better than large).

The other problem with a velocity matched ion and electron stream is that as they penetrate a magnetic field, their gyromotion will be in opposite directions. This would again lead to some charge seperation. The magnitude of this problem depends on B field strength. I again wonder if this is why the illustrations I have seen show the neutral beam guns with long tubes that penetrate to near the center of the reaction space. If shielded (iron tube) the magnetic fields would not effect the beam till it was near it's target penetration. The draw back of this is that there is a solid structure within or very near the plasma space- Loss of plasma heat and sputtered contaminates may be an issue.

I have seen mention that very high energy neutral beams (>100 KeV) requires negatively charged ions in the mix. This may suggest that the ' neutral beam' is indeed made up of charged species to a large extent, not a high speed stream made up of almost all neutral atoms.

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

happyjack27
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Re: Lockheed Martin news

Postby happyjack27 » Wed Dec 14, 2016 7:41 pm

D Tibbets wrote: With separate ion and electron guns matched for velocity, not energy, this charge separation would be minimized, at least till the ions and electrons thermalized with each other- which I understand is a relatively slow process due to the different momentum (the same consideration that governs neutron thermalization in a substrate, low molecular weight atoms are much better than large).


i was thinking the electrons would start out at 0KE, and then the ions would pull them up to matched velocity. but starting out at matched velocity is similiar enough. i'm sure they'll thermalize but as you say it's a slow process and it only needs to stay relatively non-thermal for about half a meter - until it enters the confinement region of the wiffleball. just long enough to get it through the point cusp.


The other problem with a velocity matched ion and electron stream is that as they penetrate a magnetic field, their gyromotion will be in opposite directions. This would again lead to some charge seperation. The magnitude of this problem depends on B field strength.


As is often quipped in compsci, "that's not a bug, it's a feature."

we WANT charge separation exactly where the magnetic field is highest. up to then, the electrons will by gyrated away from the center by the mag field much more than the ions will. so you'll get radial charge separation. but then that charge separation is going to pull the electrons back towards the center much more (in terms of acceleration) than it pulls the ions towards the outside. and that's what we care about - keeping the electrons towards the center so they make it through the point cusp on initial injection. (ions it's really no matter as they're dominated by space charge, not mag field.)

(specifically, treating the ions as an infinite cylinder, that's going to create a 1/r voltage gradient, thus providing a constant centralizing force for the electrons, regardless of their distance from the center. (and de-centralizing force for the ions.) this would mean they'd oscillate / orbit about the central axis, but thermalization will presumably dampen these oscillations, leading to an overall focusing effect.)

then as soon as we're through the cusp, we want any neutrals to ionize - we want charge separation. and we have exactly what we need for that: a high B field.

D Tibbets
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Re: Lockheed Martin news

Postby D Tibbets » Wed Dec 14, 2016 8:35 pm

Mmm... interesting and enlightening, though use of a cusp seems unnecessary to detrimental. In a Polywell or Lockheed design with cusps, the recirculating electron (and possibly ion) current would bombard the neutral beam gun tube- probably bad. And, most plasma containment schemes do not have cusps, so the only entry method is through the magnetic field, thus the obvious benefit of a neutral beam- either truly neutral atoms, or tightly constrained mixed beam of ions and electrons. Mentioning neutral beams in cusps does perhaps offer a method to improve injection efficiency, at least in the Lockheed design. In the Polywell it would seem to conflict with electrostatic ion containment, at least with a velocity matched ion- electron beam. In the Polywell (at least the WB6 version), the "neutral beam" was puffed through the B field away from a cusp at very low energies. In a picture of WB7 the gas puffer appears to have been at a face centered cuff. Mmm... is that a significant difference?

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


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