EMC2 website upgrade in progess

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

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D Tibbets
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Re: EMC2 website upgrade in progess

Post by D Tibbets »

There are two components to electron optics or focusing. One is the internal distribution of electrons - mostly radial motions versus mostly circular near the Wiffleball border. Interactions with ions also plays a very important role in potential well shape.

The other consideration is focusing electrons down the throat of a cusp in order to minimize external mirroring and rejection of electrons trying to enter the machine. This seems to have become a very important limiting consideration.
Apparently WB8 and Mini b have used high voltafge e-guns placed at considerable radial distance from the magrid. This is much different from WB6 e-guns which were closer, low voltage. Electron emission from WB8, etc. guns would be primarily thermionic emission and this has well defined limits on flux versus surface area. In WB6 the e-guns used thermionic emission, but also ion impacts to drive electron emission. The magrid served as the extractor. This is mentioned in the patent. I do not know what the ion impact contribution was but I believe it must have been much more significant than in WB8. The newer e-guns therefor are lagging in capacity, despite more sophistication .

The question I have is why this radically different approach was adopted? What tradeoffs favor this alternate approach?

Dan Tibbets
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Tom Ligon
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Re: EMC2 website upgrade in progess

Post by Tom Ligon »

Every Polywell with thermionic emitters will have an issue with ions impacting the emitters. Relative to the plasma, the emitter MUST be negatively charged. Ions can't resist it. As soon as you have some stray ions outside the magrid, there will be high energy impacts with the emitters, heating the emitters further. In fact, if you let it get out of control using the more efficient types, you'll blow the low work-function components (things like barium and cesium) off the surface and kill the emitter.

The whole exercise with old-school emitters such as tungsten filaments or thoriated tungsten is that this sort of deactivation is less likely.

At one point I was looking at diamond films or the ends of carbon nanotubes as an emitter. Ion impact will set if off. Graphene will probably work, too.

happyjack27
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Re: EMC2 website upgrade in progess

Post by happyjack27 »

D Tibbets wrote: The other consideration is focusing electrons down the throat of a cusp in order to minimize external mirroring and rejection of electrons trying to enter the machine. This seems to have become a very important limiting consideration.
Dan Tibbets
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that is all.

D Tibbets
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Re: EMC2 website upgrade in progess

Post by D Tibbets »

Tom Ligon wrote:Every Polywell with thermionic emitters will have an issue with ions impacting the emitters. Relative to the plasma, the emitter MUST be negatively charged. Ions can't resist it. As soon as you have some stray ions outside the magrid, there will be high energy impacts with the emitters, heating the emitters further. In fact, if you let it get out of control using the more efficient types, you'll blow the low work-function components (things like barium and cesium) off the surface and kill the emitter.

The whole exercise with old-school emitters such as tungsten filaments or thoriated tungsten is that this sort of deactivation is less likely.

At one point I was looking at diamond films or the ends of carbon nanotubes as an emitter. Ion impact will set if off. Graphene will probably work, too.
My limited understanding is that the ion bombardment was a good thing in WB6, it increased the electron emission of the filaments. Of course it also sputtered off metal, etc. The patent application suggested that the distance of the filaments outside the machine was critical- too close and you have problems like in WB5 where the central potential well was overcome by the potential of the e-gun derived cloud of electrons outside the cusp and this destroyed the electrostatic ion containment. The e- gun filaments being too far away is a problem because of emitter beam spread leading to decreased injection efficiency. Also the ions that do escape are less likely to hit the filamants due to spacial spread due to inverse square law effects (and possibly external ions sticking to B field lines and being carried away from the filamants.There is a Goldilocks location (maybe). All of this reasoning applies to the WB6 where the e-gun filaments were at low voltage that was not much different from the grounded shell/ Faraday cage . The magrid served as the extractor for the e-guns and as such had to be within some defined distance . As such the e-guns were not a terribly attractive target for the ions. The only high voltage surface in WB6 was the positive charged magrid and it was magnetically shielded. The Mini B machine, and WB8(?) apparently has a grounded magrid and high negative voltage e-guns. The dynamics are different.

I personally prefer the high positive voltage on the magrid for this reason along with my understanding of electron recirculation. I suspect that in my world at least, the final solution may be a high positive potential on the magrid and a moderate negative on the distant e-gun. Electron focusing is thus achieved with this push - pull approach, much of the recirculation effect is retained, etc. An example might be a magrid potential of +75 KV and an e-gun voltage of -5 KV. Net electron acceleration would be 80 KeV. Throw in a set of direct conversion grids and the optimum compromise picture becomes even more complex.

Dan Tibbets
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D Tibbets
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Re: EMC2 website upgrade in progess

Post by D Tibbets »

And, just to further deviate from this thread topic. A near neutral beam injection may provide the best solution. Combine a low energy electron and high energy ion beam and shoot it down a cusp. The space charge induced beam spread will be less and tight cusp penetrating flows may be achieved. A small electron excess (1 ppm) or a separate low power (and thus less spread) electron beam would establish the internal potential well. The high energy ions would drag the electrons along to an extent but most of the electron acceleration would be from the positive charged magrid. The ions would be decelerated by the magrid so that they penetrated the cusp at the least KE feasible (giving up their KE to the magrid). The ions would thus be at low energy at the top of their internal potential well. Some balance of ion and electron energies at the beam origins might be workable.

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

Tom Ligon
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Re: EMC2 website upgrade in progess

Post by Tom Ligon »

If I were to try my hand at a Polywell, it would be based on PXL-1. Not because it is the most promising, but because it did mysterious things I didn't understand, and we retired it before we got to the bottom of it. It specifically did NOT have a charged magrid.

I wouldn't hold my breath on significant updates of the website. I think I can safely spill one bean on this from talking with Jay ... he was not at all happy with the previous content, which he inherited. He pulled down the old stuff and put up the present teaser, but is not sure where he wants to go with it.

If any of you have any useful suggestions, perhaps if you discuss them here, Jay will drop by and read it?

mvanwink5
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Re: EMC2 website upgrade in progess

Post by mvanwink5 »

Take a look at GF's web site and follow the concepts. Redo the EMC2 website as good business practice.
http://www.generalfusion.com
Counting the days to commercial fusion. It is not that long now.

crowberry
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Re: EMC2 website upgrade in progess

Post by crowberry »

EMC2 has finally updated the website. It is a collection of links to Polywell and some general fusion material and there is a new WB-8 picture on the page with plasma in it. The design is rather basic, but it is a big step forward compared to the previous version.

ladajo
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Re: EMC2 website upgrade in progess

Post by ladajo »

Nice pic choice, good happy snap of a classic Spikeyball.

And the wheels grind on...
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)

mvanwink5
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Re: EMC2 website upgrade in progess

Post by mvanwink5 »

However, that website has nothing to do with EMC2 that had the Navy contract:
EMC2 Fusion Development Corporation is a nonprofit organization comitted to research and development in frontier energy technologies, in particular nuclear fusion energy. EMC2 Fusion Development Corporation is not affiliated with Energy Matter Conversion Corporation (EMC2) or any commercial entity mentioned on this page.
(as KitemanSA has repeatedly pointed out and is clearly stated on the new webpage for the site just referred to).
Counting the days to commercial fusion. It is not that long now.

ladajo
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Re: EMC2 website upgrade in progess

Post by ladajo »

They have to stay separate to maintain the Non-profit status for FDC.
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)

mvanwink5
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Re: EMC2 website upgrade in progess

Post by mvanwink5 »

So, why doesn't EMC2, the for profit company, create a website? Why is the non profit organization doing it? Seems a bit odd to me unless EMC2 is trying to get non profit funding...

edit:

Thanks Tom for the below response...
Last edited by mvanwink5 on Thu Feb 26, 2015 4:13 pm, edited 2 times in total.
Counting the days to commercial fusion. It is not that long now.

Tom Ligon
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Re: EMC2 website upgrade in progess

Post by Tom Ligon »

The EMC2FDC website perdates the present reincarnation of EMC2. I don't think KickStarter existed then, but the hope was to drum up some funding essentially like what KickStarter, GoFundMe, etc does. Its kind of a leftover. However, it does have the advantage of not having Navy strings attached, so it can look into things that are not covered by the contract they eventually got.

I don't know the present intent EMC2 has for the FDC non-profit, but it would be a nice vehicle for things like doing talks to university groups.

I personally operate as two entities. One is my DBA consulting company, Assorted Technical Expertise. But I also run Rattlesnake Ridge Research. At the moment, they are both "non profit", but the intent is for ATE to do the paid consulting. RRR is an umbrella for my hobbies and pro-bono work ... stuff that costs me money and was never intended to make any.

raelik
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Re: EMC2 website upgrade in progess

Post by raelik »

Tom Ligon wrote:The EMC2FDC website perdates the present reincarnation of EMC2. I don't think KickStarter existed then, but the hope was to drum up some funding essentially like what KickStarter, GoFundMe, etc does. Its kind of a leftover. However, it does have the advantage of not having Navy strings attached, so it can look into things that are not covered by the contract they eventually got.
So no plans to make a KickStarter, IndieGoGo, etc for the EMC2FDC? I know Famulus had his fairly small one, but that was just to fund his personal project, not an overarching one to help fund the science.

Tom Ligon
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Re: EMC2 website upgrade in progess

Post by Tom Ligon »

I suspect those days are behind them. I'm not privy to the current business plan, but having been an informal go-between back around 2007, I suspect they have some sincere interest with adequate capital.

Alas, this time around, presuming there is money interested, it doesn't have to go thru me, so I'm left guessing with the rest of you.

I did score some of the yard sale goodies from Famulus. I wish I were in a position to carry that project on, but the lottery tickets have not cooperated.

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