crazy idea for sputtering

Discuss the technical details of an "open source" community-driven design of a polywell reactor.

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ohiovr
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Post by ohiovr »

There is always D-D to start - until the pB11 difficulties can be worked out.
Even deuterium fusion has high energy charge particle products: according to wiki:

http://en.wikipedia.org/wiki/Nuclear_fu ... _reactions

50% of the time D+D fusion results in:
1MeV triton and a 3MeV proton

the other 50% the fusion results in:
.8MeV 3He and a 2.6MeV neutron

Well 3 out of the 4 products should have energies and charges capable of sputtering the magrid although much less so than P+11B fusion. Even at maybe 1/8th as bad it still is bad.

ohiovr
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Post by ohiovr »

Maybe Nebel is right (I certainly hope he is). Take 3He+3He fusion. The polywell will be containing a potential well of about 100 KeV and the reaction products are no more than 12.9 Mev. The ratio of reaction product energy to containment energy is 129. So a magnetic container 100x as powerful may not at all contain the reaction products. 10 teslas may be plenty powerful enough to steer all the reaction products away from the coils. The electron and Ion guns would be eroded without some intervention. I think that can be solved.

TallDave
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Post by TallDave »

If they're averaging a thousand transits on their way out, how many could be actually hitting the Magrid? One in a million? Am I way off here?

ohiovr
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Post by ohiovr »

And wouldn't some of the particles collide with the structures connecting each magrid coil to each other? Whatsitcalled?

I would think that even 1 in a million particles colliding with metal parts would cause nearly immediate problems.

Aero
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Post by Aero »

ohiovr wrote:And wouldn't some of the particles collide with the structures connecting each magrid coil to each other? Whatsitcalled?

I would think that even 1 in a million particles colliding with metal parts would cause nearly immediate problems.
That brings up questions. The connecting "Nubs" are used to maintain current flow in the ambient temperature electro-magnet coils. That is, interconnection insures that there is a single current flowing through all of the coils of the Magrid. It seems that the requirement is that the current in each coil of the Magrid must be equal or nearly so.

First question, "What is the tolerance on magnetic field variation in the coils of the Magrid?"

Second question, "Is this interconnecting design absolutely required for ambient temperature electro-magnets?"

Third question, "Are Nubs connecting the coils necessary for a superconducting magrid?"
Aero

KitemanSA
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Post by KitemanSA »

Aero wrote: That brings up questions. The connecting "Nubs" are used to maintain current flow in the ambient temperature electro-magnet coils. That is, interconnection insures that there is a single current flowing through all of the coils of the Magrid. It seems that the requirement is that the current in each coil of the Magrid must be equal or nearly so.

First question, "What is the tolerance on magnetic field variation in the coils of the Magrid?"

Second question, "Is this interconnecting design absolutely required for ambient temperature electro-magnets?"

Third question, "Are Nubs connecting the coils necessary for a superconducting magrid?"
Fourth question why are we talking nubs? The magnetically protected replacement for them have already been proposed.

And by the way, the nubs weren't to balance the current but to provide it thru the whole system and to support the other 5 coils. Only the lower coil was connected to the rest of the world thru ceramic legs. The side and top magnets were all connected thru the "nubs".

Aero
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Post by Aero »

KitemanSA wrote:
Aero wrote: That brings up questions. The connecting "Nubs" are used to maintain current flow in the ambient temperature electro-magnet coils. That is, interconnection insures that there is a single current flowing through all of the coils of the Magrid. It seems that the requirement is that the current in each coil of the Magrid must be equal or nearly so.

First question, "What is the tolerance on magnetic field variation in the coils of the Magrid?"

Second question, "Is this interconnecting design absolutely required for ambient temperature electro-magnets?"

Third question, "Are Nubs connecting the coils necessary for a superconducting magrid?"
Fourth question why are we talking nubs? The magnetically protected replacement for them have already been proposed.

And by the way, the nubs weren't to balance the current but to provide it thru the whole system and to support the other 5 coils. Only the lower coil was connected to the rest of the world thru ceramic legs. The side and top magnets were all connected thru the "nubs".
Fourth question response - I respectfully submit that one unproven proposal does not preclude a second unproven proposal, so talking about nubs is fair game.

I further submit yet a third unproven proposal, being that by using a purpose built vacuum chamber, all of the Magrid coils could be excited through ceramic legs, all else (Questions 1-3 above) being equal. This would eliminate the nubs entirely.

Quoting from the current contract:
Based upon this review, the contractor will modify the existing wiffleball #7 (WB-7) device by installing compact, high temperature coil joints.
This leads me to think that there may be a reason to retain the nubs, which could be to provide the exact same current through all of the coils. This directs me back to questions 1-3.

Of course another reason to install compact, high temperature coil joints could simply be to enable higher power testing with the existing WB-7 as modified (that is, WB-7.1).
Aero

MSimon
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Post by MSimon »

TallDave wrote:If they're averaging a thousand transits on their way out, how many could be actually hitting the Magrid? One in a million? Am I way off here?
At 10T 3 MeV Alphas have a gyroradius of 5 cm. Which says that any fusions that happen more than 5 cm from the coils get deflected. Actually the distance is somewhat less due to the fact that the field at the coil shell is higher than the field at the center of the coil. But the magnetic geometry is complicated. At the center of the reaction space the gyroradius is "infinite". Near the coils it is small. Which says the charged particles that are moving will tend to form a shell that is near the magnets.

Normally I'm pretty pretty good at visualizing particles in fields and machines in motion etc. But I got to say that imagining all the stuff going on and trying to figure out which effects predominate without experimental numbers is tough. It hurts my head. Fortunately I love pain and chaos. Which makes me a good candidate for a R&D engineer or a mental hospital. Take your pick.
Engineering is the art of making what you want from what you can get at a profit.

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