Lawaranceville E-Newsletter

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

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RERT
Posts: 118
Joined: Mon Jun 02, 2014 9:10 pm

Re: Lawaranceville E-Newsletter

Postby RERT » Mon Apr 25, 2016 8:07 am

Me too. Hope it soon moves on from being a charity case! R.

Skipjack
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Re: Lawaranceville E-Newsletter

Postby Skipjack » Sat May 28, 2016 11:30 pm


zapkitty
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Re: Lawaranceville E-Newsletter

Postby zapkitty » Wed Jun 29, 2016 7:08 pm

And yet again :)...

http://us8.campaign-archive2.com/?u=879 ... 6559f2f07d

From the Summary:

LPPF Reports New Record Temperatures To Int'l Conference

Hydrogen-Boron Groups Announce Advances, Plan Closer Collaboration

Z-pinch Device Gets 6 J Fusion with Deuterium

:)

DeltaV
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Re: Lawaranceville E-Newsletter

Postby DeltaV » Thu Jun 30, 2016 3:24 am

Link from the above:

Avalanche proton-boron fusion based on elastic nuclear collisions
https://www.researchgate.net/publication/303293228_Avalanche_proton-boron_fusion_based_on_elastic_nuclear_collisions
Abstract
Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a layer of boron dopants in a hydrogen enriched target have produced around 109 alphas. We suggest that these unexpected very high fusion reactions of proton with 11B indicate an avalanche multiplication for the measured anomalously high nuclear reaction yields. This can be explained by elastic nuclear collisions in the broad 600 keV energy band, which is coincident with the high nuclear p-11B fusion cross section, by the way of multiplication through generation of three secondary alpha particles from a single primarily produced alpha particle.

zapkitty
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Re: Lawaranceville E-Newsletter

Postby zapkitty » Thu Jun 30, 2016 6:16 am

DeltaV wrote:Link from the above:

Avalanche proton-boron fusion based on elastic nuclear collisions


Yep, that came out last month, i think... not quite a fissile-style chain reaction but definitely indicates more burn for the buck.

Seems that the posited "two strong - one weak" alpha output might have more dividends to pay than just a slightly extended burn and higher conversion efficiency....

D Tibbets
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Re: Lawaranceville E-Newsletter

Postby D Tibbets » Sat Jul 02, 2016 11:39 am

DeltaV wrote:Link from the above:

Avalanche proton-boron fusion based on elastic nuclear collisions
https://www.researchgate.net/publication/303293228_Avalanche_proton-boron_fusion_based_on_elastic_nuclear_collisions
Abstract
Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a layer of boron dopants in a hydrogen enriched target have produced around 109 alphas. We suggest that these unexpected very high fusion reactions of proton with 11B indicate an avalanche multiplication for the measured anomalously high nuclear reaction yields. This can be explained by elastic nuclear collisions in the broad 600 keV energy band, which is coincident with the high nuclear p-11B fusion cross section, by the way of multiplication through generation of three secondary alpha particles from a single primarily produced alpha particle.


Huh?
First, I'll assume they mean 10^9 alphas, or 10e9 alphas. Production of three alphas from one primary alpha? Are they referring the alphas heating the local protons or borons?- a local ignition type of interaction? Or, as I suspect, the initially fusion produced excited carbon12 isomer (not an alpha) breaking down (fissioning) into one alpha plus an excited Beryllium8 isomer- whichthen quickly breaks down (fissions) into two additional alphas. This is the well accepted highly dominate pathway for this reaction and is nothing new. The cross section for p-B11 fusion may be better than the classic estimate for those temperatures though.

PS: I am a fan boy of the narrow fusion cross section peak at ~ 120 KeV. I fantasize that their results may show the extra fusion within the broader thermalized energy spread of the fuel elements that occurs at this lower energy. This would not only show some improvement in overall pB11 fusion yields, but also the potential to operate in this narrow energy resonance cross section peak in order to reduce Bremsstruhlung losses significantly. If this fusion cross section resonant peak shows a measurable improvement in the yield of a hotter thermalized plasma with an average temperature of 600 KeV, then any non thermalized machine (like the Polywell claims) could concentrate at this lower energy, yielding good fusion yields with engineering advantages and energy cost savings (~ 10 times less Bremsstruhlung losses) than operation at the higher traditional temperatures.

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

Ivy Matt
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Re: Lawaranceville E-Newsletter

Postby Ivy Matt » Sat Jul 02, 2016 8:47 pm

There's a link to download the full-text PDF from the page DeltaV linked to. The number of alphas produced is indeed 10 to the 9th power. Cut-and-paste operations often fail to preserve superscripts and other formatting.

By my reading of the paper, what they are referring to is essentially the same thing as the alpha heating the tokamak folks (and NIF) are depending on to achieve ignition. They focus in particular on collisions of alphas with protons at rest, accelerating the protons to energies of ~600 keV. There's an illustration of the process in the paper, although it depicts the fusion reactions producing three alphas with 2900 keV each, which is contrary to my understanding of the p-B11 reaction.

Here's the takeaway from the paper:
Computations done for cylindrical trapping with ultra-high magnetic fields under the assumption of the avalanche show that a 30 kJ laser pulse of ps duration could produce more than GJ energy in alpha particles.

By comparison, NIF was designed to deliver upwards of 1.8 MJ of energy to its targets.
Temperature, density, confinement time: pick any two.

zapkitty
Posts: 267
Joined: Fri Apr 09, 2010 8:13 pm

Re: Lawaranceville E-Newsletter

Postby zapkitty » Mon Aug 15, 2016 4:25 pm

The Return of the Bride of the Son of the August 2016 LPP Report:

http://us8.campaign-archive1.com/?u=879 ... 6559f2f07d

RERT
Posts: 118
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Re: Lawaranceville E-Newsletter

Postby RERT » Mon Aug 15, 2016 4:44 pm

But to get to the full planned current of 2.8 MA, the inductance of other parts of the FF-1 circuit must be reduced, so more energy is available inside the vacuum chamber, and less is wasted in magnetic field energy outside the chamber. The research team has some concrete ideas of how to do this, but we need help in testing them out. LPPFusion needs paid help from someone who has done 3D modeling of pulsed power circuits and has present access to the software required—such as COMSOL. If you have these specialized skills, or know someone who does, please get in touch with us and we can give you more details and solicit a proposal.


(Their starting point is 1.1 MA)

I have neither the expertise nor the software. Does anyone here? I will forward this request where I can, perhaps others might also think that worthwhile.

D Tibbets
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Re: Lawaranceville E-Newsletter

Postby D Tibbets » Sat Nov 05, 2016 12:34 am

Here is some news from LPP. It seams that tungsten has caused as much problems as hoped for gains .Beryllium is now the new hope. They have not completely abandoned tungsten but are planning modifications to perhaps circumvent some of the problems while they wait for the beryllium.

http://lppfusion.com/wp-content/uploads ... ber-28.pdf

Also, see the News at the LPP site.

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

ladajo
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Re: Lawaranceville E-Newsletter

Postby ladajo » Sat Nov 05, 2016 12:27 pm

Thanks for sharing Dan, I had been wondering of late where they are at. This is indicative of real science, two steps forward, one step back; one step forward, two steps back. The effort in itself growing the knowledge base in depth and breadth. And occasionally, forwards outpace backs.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

Skipjack
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Re: Lawaranceville E-Newsletter

Postby Skipjack » Sun Nov 06, 2016 4:42 am

It seems like many of their problems are engineering and material issues rather than physics issues. Wonder when/if they will hit a wall where the actual physics turns out to be the limiting factor.
Also wondering whether Uri Shumlak's FuZE will be affected by the same problems or if they have some solutions that could help LPP.

ladajo
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Joined: Thu Sep 17, 2009 11:18 pm
Location: North East Coast

Re: Lawaranceville E-Newsletter

Postby ladajo » Sun Nov 06, 2016 5:04 pm

The $64 question:

Wonder when/if they will hit a wall where the actual physics turns out to be the limiting factor.


I suspect it will be stability related.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)

What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

RERT
Posts: 118
Joined: Mon Jun 02, 2014 9:10 pm

Re: Lawaranceville E-Newsletter

Postby RERT » Sun Nov 06, 2016 6:10 pm

Not sure what you mean. Their experiments and reactor design are pulsed, rather than steady state. What kind of stability are you talking about?

ladajo
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Location: North East Coast

Re: Lawaranceville E-Newsletter

Postby ladajo » Sun Nov 06, 2016 7:34 pm

The actual ability for the pinch to form and stabilize at full power. They are seeing some success, however, there is a long row to hoe.
So many factors influence this. Contamination, materials, geometry, power feed cleanliness, etc...
They have been in the "we don't know what we don't know" mode for some time now. Not a bad place, until they trip and face plant. For now, nothing uncovered has been fatal. I hope they keep rolling.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)

What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)


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