Dr. Park invites questions from the community

Consider specific people in the fusion research community, business, or politics who should be made aware of polywell research, and how we might reach them.

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D Tibbets
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Re: Dr. Park invites questions from the community

Postby D Tibbets » Thu Feb 04, 2016 12:12 am

Only ten questions? Where to begin...

The machine designed to achieve and demonstrate high Beta effects had wide separations between magnets. Does this reflect improved cusp confinement compared to WB6 and imply a need to keep ExB losses from becoming dominate? For that matter, without a deep potential well, is Ion cusp losses dominating the picture over electron cusp losses in this machine, at least as higher Beta is reached?

How much did the internal magnetic field measuring coaxial cables limit achievable Beta?

Is there a reconciliation between this machines low Beta cusp confinement numbers and those claimed for WB6? WB6 was ~ 60 passes , while this machine was ~7 passes. Given that simple biconic mirror confinement was quoted as ~ 5-8 passes (in the older patent application), the numbers for this machine ('Mini B' as it has been called here) seem small. Is the increased magnet spacing distance combined with the overall smaller size (relative differences magnified) significant, despite the increased B field strengths?

The reported neutron counts for the relatively large reaction space in WB7 and 8 [EDIT- error, no known counts from WB8 ] seem modest compared to simple amateur fusor reports with only modestly higher voltages, and this is ~ 3 orders of magnitude less than that claimed for WB6. Was deep potential wells obtained in WB7,and 8? You mention that deep potential wells was obtained in 1995, how about in WB7 and/ or 8?

The bridging nubs may have been a major source of sputtered plasma in WB6 with an unknown percentage of the greater than 40 Amps of high energy electron current hitting them. Was this found in WB7.0? Did the elimination of these nubs starve the machine of a plasma source?
If highly positively charged magrid cans leads to loss of central dominate potential well in the corner cusps, can this be mitigated by moving the charge to a ribbon on the outer surface of the cans-effectively increasing the radius of the accelerating positive electrode by a few cm or more?
Bussard reported that the average speed of ~ 10 KeV injection energy electrons in WB6 was about 10 million cm/s. This presumably reflects the effects of a deep potential well, with the electrons spending a major portion of their lifetimes at significantly slower speeds. Without a deep potential well the average speed is significantly higher. This is significant for Bremsstruhlung radiation and also for confinement as measured by time, not so much for number of passes measure. Is this consideration reasonable?

Can a neutral beam of slow electrons matched with fast ions serve as both an efficient electron injection and cool ion injection source? This presupposes a positive charge on the magrid (outer surface only charge tolerable?) to accelerate the electrons while slowing the ions .This may serve to keep the beam more narrow than pure electron beams of the same current while also allowing for cold ion injection. The ions would give up most of their energy to the positive magrid (a direct conversion effect) and enter the machine at low voltage cool conditions. Further cooling inside the machines through radiation losses might keep them adequately trapped in the potential well. Better electron injection efficiency is hopefully achieved. This opens up other questions and compromises, but is this a possible solution?

Without sufficient positive charge on the magrid, recirculation is only possible by the electrons (and ions for that matter) looping around to another cusp. Is this possible to do with sufficient efficiency despite ExB and instability issues? Will an additional layer of external magnets be necessary? This seems to be the approach championed by Dr McGuire at Lockheed. Do you feel that electron recirculation is a needed feature for the Polywell, or can primary high Beta cusp confinement of electrons suffice?

As asked by another poster, do you feel a D-D half cat reaction is possible? In my limited understanding a machine that requires a dedicated D-T reaction for profitability adds a lot of additional challenges, especially from an economical perspective.

What is your take on several mechanisms that have been proposed for application to the Polywell. These include edge annealing, effect of the potential well on Bremsstruhulung losses, effect of diluting the high Z fuel (He3 or B11) on Bremstruhlung losses versus fusion output, etc.


Dan Tibbets
Last edited by D Tibbets on Thu Feb 04, 2016 1:39 am, edited 1 time in total.
To error is human... and I'm very human.

ladajo
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Re: Dr. Park invites questions from the community

Postby ladajo » Thu Feb 04, 2016 12:21 am

Dan,
Where did you see neutrons produced in WB-8?
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)

D Tibbets
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Re: Dr. Park invites questions from the community

Postby D Tibbets » Thu Feb 04, 2016 1:34 am

ladajo wrote:Dan,
Where did you see neutrons produced in WB-8?



This mentions WB7 Neutron counts on slide / page 7
My recollection was that WB8 was also mentioned, but my memory failed me. Oh well :oops: . I will edit the previous post to reflect this...


http://iec.neep.wisc.edu/usjapan/16th_U ... lywell.pdf

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

mvanwink5
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Re: Dr. Park invites questions from the community

Postby mvanwink5 » Thu Feb 04, 2016 1:54 am

Do you feel that electron recirculation is a needed feature for the Polywell, or can primary high Beta cusp confinement of electrons suffice?
Yes, I had thought the point of achieving cusp closure and proving Grad's conjecture was that recirculation was a bust in Polywell.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

ladajo
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Re: Dr. Park invites questions from the community

Postby ladajo » Thu Feb 04, 2016 3:07 am

I think this may be a central point of misunderstanding heldover from the old days.
I see it as an oscillation in a cusp, with some that make it out and are lost.
I do not see the out one cusp in another as viable in any construct for a polyhedron machine.
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: Dr. Park invites questions from the community

Postby mvanwink5 » Thu Feb 04, 2016 3:34 am

Once on the other side of the cusp it should be history. Lockheed, though, is counting on major recirculation.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

ladajo
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Re: Dr. Park invites questions from the community

Postby ladajo » Thu Feb 04, 2016 2:00 pm

To me, the big question is "how many are some?"
If this number is low enough during fusion conditions then we are onto something.
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)

D Tibbets
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Re: Dr. Park invites questions from the community

Postby D Tibbets » Thu Feb 04, 2016 3:05 pm

mvanwink5 wrote:Once on the other side of the cusp it should be history. Lockheed, though, is counting on major recirculation.


Ditto...

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

ltgbrown
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Re: Dr. Park invites questions from the community

Postby ltgbrown » Thu Feb 04, 2016 7:21 pm

ladajo wrote:To me, the big question is "how many are some?"
If this number is low enough during fusion conditions then we are onto something.


That to me is the big question. Everything else is fun details to start thinking about.
Famous last words, "Hey, watch this!"

D Tibbets
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Re: Dr. Park invites questions from the community

Postby D Tibbets » Fri Feb 05, 2016 5:02 pm

ltgbrown wrote:
ladajo wrote:To me, the big question is "how many are some?"
If this number is low enough during fusion conditions then we are onto something.


That to me is the big question. Everything else is fun details to start thinking about.


Well, perhaps. One of the basic requirements as put forth by Dr Bussard, is that the Polywell must be an open machine to allow for recirculation. Without this consideration, a closed design may be possible. The cusp plugging/ cold electrons in the cusp issues remain though. IE: Adequate high Beta cusp electron containment may be possible, but it is benificial only if a deep central potential well for ions can be maintained as well. In this regard the open machine may be required, not for recirculation of electrons, but to maintain a central potential well. This in contrast to the Lockheed design, which is an open machine (sort of) for purposes of recirculation (of both electrons and ions), not for maintaining a potential well (there is none).

"Is this a reasonable picture of the issues?" could be added to the front to make it question for Dr Parks.

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

ladajo
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Re: Dr. Park invites questions from the community

Postby ladajo » Fri Feb 05, 2016 5:36 pm

Dan, as I understand it these days, any (e-) that transits a cusp is gone in Polywell. Recirculation is not a factor.
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: Dr. Park invites questions from the community

Postby mvanwink5 » Fri Feb 05, 2016 10:52 pm

I had understood that cold electrons accumulating in cusps would be countered by neutral beam injection or hot electron injection at the cusps.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

ladajo
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Re: Dr. Park invites questions from the community

Postby ladajo » Sat Feb 06, 2016 1:33 am

And if that cusp does not have a beam?
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: Dr. Park invites questions from the community

Postby mvanwink5 » Sat Feb 06, 2016 2:46 am

Maybe enough cusps will do, otherwise every cusp?
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

hanelyp
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Re: Dr. Park invites questions from the community

Postby hanelyp » Sat Feb 06, 2016 3:30 am

One BIG question: what uncertainties remain to be resolved?
The daylight is uncomfortably bright for eyes so long in the dark.


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