POPS system

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

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Zixinus
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POPS system

Postby Zixinus » Tue Jul 17, 2007 12:32 pm

I just found this paper published in no less than the Physical Review Letters:
"Experimental Observation of a Periodically Oscillating Plasma Sphere (POPS) in a Gridded Inertial Electrostatic Confinement Device" by Park, Nebel, Stange and Murali, 2005.
http://link.aps.org/doi/10.1103/PhysRevLett.95.015003
As you might imagine getting a paper on IEC into PRL is, well, not easy. D.C. Barnes had one in '93 and before that you'd have to go back to the 60's I believe.

Park,Nebel,Strange,Murali is recognition and follow up of work done by Barnes and Nebel (Los Alamos) in '98:
"Stable, thermal equilibrium, large-amplitude, spherical plasma oscillations in electrostatic confinement devices" Physics of Plasmas, Barnes and Nebel, 98
http://link.aip.org/link/?PHPAEN/5/2498/1

AFAICT the POPS reasoning goes as follows:
It was recognized that collisions pointed out by Nevins/Rider for fusors/Polywell IEC fusion made net power unlikely.
"The high energy cost of maintaining a beamlike ion energy distribution makes it difficult to produce net fusion power and is considered to be a crucial obstacle facing IEC based energy devices..." - which we well know ad nauseum on this forum. So B & N came up w/ an oscillating scheme where _all_ of the ions are phased locked and move towards the focus together. Moreover they did the analytical work to prove on paper that this could be done. This PRL paper is observation of the thing, living, in the UW lab. They use a virtual cathode ala Tuck et al or Bussard:

"...A new electrostatic plasma equilibrium that should mitigate this problem has been proposed by Barnes and Nebel [12,13]. This concept uses electron injection into a spherical device to produce a virtual cathode with a harmonic oscillator potential (constant electron density). An ion cloud immersed in the virtual cathode [referred to as the periodically oscillating plasma sphere (POPS)] will then undergo a harmonic oscillation where the oscillation frequency is independent of the amplitude. By tuning the external radio-frequency (rf) electric fields to this naturally occurring mode, it is then possible to phase lock the ion motions. This simultaneously produces very high densities and temperatures during the collapse phase of the oscillation, when all ions converge to the center with their maximum kinetic energies. It has been shown that an analytic solution for the POPS oscillation exists and has the remarkable property that it maintains the ions in local thermodynamic equilibrium at all times [12]. In particular, the equilibrium state survives even though the plasma density and the temperature may vary by several orders of magnitude during the POPS oscillation..."

Barnes&Nebel noted in a related paper that there was a space charge problem that had to be solved for a working POPS. Then in April of this year this came out:
"Space Charge neutralization in IEC plasmas", Evstatiev, Nebel, Chacon, Park, Lapenta in Physics of Plasmas.
http://dx.doi.org/10.1063/1.2711173


Image

Discuss. Also, how well could this thing be applied to Polywell?

MSimon
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Postby MSimon » Mon Aug 13, 2007 3:57 pm

This is very important. If it can be made to work with Polywell it could do one or more of the following

1. reduce reactor size
2. Increase power out
3. Allow a reasonable amount of fusion at the 150 Kev resonance point lowering Bremss losses

Depending on the gain available you might be able to do more than one of the above.

POPS is tunable. In theory you could tune it to electrons, or protons, or any atom. However, getting electrons crashing around is not much use.

In the pB11 system you could tune it to protons or B11 depending on what you wanted to accomplish.

With a D-D system you get the effect squared. Pretty handy.

As I recall they have already managed a gain of 6.7 in the lab. If it doesn't cost much power and the equipment is simple this would be quite useful. If they get it up to 100 or more - heaven.

The WB-7x test reactor is designed for POPS testing.

Update:

Let me add that I have done preliminary calculations and the POPS frequency for the test reactor comes out to between 1 and 30 MHz - Broad band Amateur radio equipment could be used up to a few KW with power combiners. In fact it might be possible to use such equipment down to 100 KHz if required.

jlumartinez
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Postby jlumartinez » Mon Aug 13, 2007 10:02 pm

Does somebody know anything about these guys: http://www.fpgeneration.com/index.html ?
They state to have developed and quasi spherical IEC fusion reactor with POPS technology. If you read their website it is interesting to see that they were working for Bussard in EMC2 some years ago. They also use a magnetic field to confine electrons. Are they talking about an special case of Polywell? Opinions?

M.Simon, what you refer as a gain of 6.7? I suppose they haven´t achieved yet a real gain of 6.7 because in that case they were in all the newspapers.

MSimon
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Postby MSimon » Tue Aug 14, 2007 5:45 am

jlumartinez wrote:Does somebody know anything about these guys: http://www.fpgeneration.com/index.html ?
They state to have developed and quasi spherical IEC fusion reactor with POPS technology. If you read their website it is interesting to see that they were working for Bussard in EMC2 some years ago. They also use a magnetic field to confine electrons. Are they talking about an special case of Polywell? Opinions?

M.Simon, what you refer as a gain of 6.7? I suppose they haven´t achieved yet a real gain of 6.7 because in that case they were in all the newspapers.


It was a density gain of 6.7 Which would translate into a power increase of 6.7 since the density increase is only by one component of the mix. Except for D-D. For D-D that translates into an effective density increase of about 45. Not trivial.

==

The FPG folks seem to be using Bussard's ideas. They claim to have a patent but list no patent number. They are looking for $$$. They do not seem to be very open about their ideas and speak in generalities.

The thing is, no one has gotten a magnetic electron confinement (MEC) IEC device to operate for longer than a fraction of a millisecond in the last 10 years.

No one has yet experimentally combined POPS and MEC.

I did a search on Alex Klein and MIX and fusion and only came up with FPG. What ever the MIX concept is there is very little published on the subject i.e. zero as far as I can tell.

jlumartinez
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Postby jlumartinez » Tue Aug 14, 2007 9:34 am

I also tried to search something about these guys and I couldn´t find anything. No papers, no patent number, no references in the web. I contact them with an email and asked about the differences with a Polywell and they answered me that their concept "is very different from Bussard's polywell, basically opposite polarity"and they stated that a patent is pending. They don´t have any experimental device yet. They are also trying to find investor

MSimon
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Postby MSimon » Tue Aug 14, 2007 11:58 am

jlumartinez wrote:I also tried to search something about these guys and I couldn´t find anything. No papers, no patent number, no references in the web. I contact them with an email and asked about the differences with a Polywell and they answered me that their concept "is very different from Bussard's polywell, basically opposite polarity"and they stated that a patent is pending. They don´t have any experimental device yet. They are also trying to find investor


Opposite polarity means they are shooting in ions. Which makes sense given their diagram. Confinement will be about 40X lower for a given magnetic field.

They are looking for some one to fund a math project first followed by a test reactor.

pstoller78
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Postby pstoller78 » Tue Aug 14, 2007 6:33 pm

I wonder if Tom would know much about Alex Klein. If they worked at EMC2
at the same time perhaps he could shed some light.

JD
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Postby JD » Tue Aug 28, 2007 10:28 pm

Greetings and may I ask a question? Wouldn't the PoPs oscillation adversely effect the migration of the ions? Specifically wouldn't this slow down the migration and cause more thermalization which I thought the Bussard approach was trying to prevent?

Not sure if I'm looking at this properly, the best quick and dirty explanation I found for PoPs was at ...

http://www.lanl.gov/p/rh_pp_park.shtml

MSimon
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Postby MSimon » Tue Aug 28, 2007 11:24 pm

JD wrote:Greetings and may I ask a question? Wouldn't the PoPs oscillation adversely effect the migration of the ions? Specifically wouldn't this slow down the migration and cause more thermalization which I thought the Bussard approach was trying to prevent?

Not sure if I'm looking at this properly, the best quick and dirty explanation I found for PoPs was at ...

http://www.lanl.gov/p/rh_pp_park.shtml

According to the LANL site you quote POPS does not affect thermal distributions. How it works with Polywell will have to be determined by experiment.

JD
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Postby JD » Tue Aug 28, 2007 11:47 pm

MSimon

Sorry, I didn't state it right, I was speaking of a PoPs system implemented with Bussard's concept as discussed earlier.

MSimon
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Postby MSimon » Wed Aug 29, 2007 12:12 am

JD wrote:MSimon

Sorry, I didn't state it right, I was speaking of a PoPs system implemented with Bussard's concept as discussed earlier.


That is a big question. I'd like to know the answer. I await further experiments.

Keegan
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GO POPS

Postby Keegan » Tue Sep 04, 2007 4:15 am

POPS is definitely a big thing. I have suspected for sometime that a working polywell will almost definitely use some form of resonant/ oscillatory drive

MSimon where does your 1-30mz come from. It would be the resonant frequency of what ?

Does anyone have access to the PDF of those journals mentioned ?.

http://scitation.aip.org/getabs/servlet ... s&gifs=yes

http://scitation.aip.org/getabs/servlet ... s&gifs=yes

I am very interested in investigating this field
Purity is Power

MSimon
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Postby MSimon » Tue Sep 04, 2007 4:51 am

A plasma container with a certain size and well drive has a characteristic frequency. The frequency is dependent on the particle mass so you can tune it to Hydrogen or Boron depending on which species you want compressed. Of course with D-D it goes as n^2/2.

This paper is a good start:

http://www.lanl.gov/p/rh_pp_park.shtml

I used the curve given to derive the constant and assumed tuning for Hydrogen in my calculations.

I assumed a radius of 1.5 to 6" to derive the formula. The actual value was not given in the text. Then based on that and a 1 to 2 m radius and the drive voltages, I came up with an approximation of the frequencies.

The frequency is strictly an electrostatic phenomenon. No magnetic field enters the equation so it is different from gyro radius.

In any case - for now the exact frequency is not too important. It can be determined by experiment. What is important to know is the approximate range as it will give us an idea of how difficult it will be to generate and control.

I may have some papers on this. I'll see if I can find the Links.

MSimon
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Postby MSimon » Tue Sep 04, 2007 5:07 am

Some more:

http://www.sherwoodtheory.org/sherwood0 ... m/3B01.pdf

One of the givens for POPS was a thermalized plasma.

The frequency may be different if the energies are bunched. Or the bunching may make the Q (electrical resonance) higher. i.e. more sensitive to control. In layman's terms it means that the useful range of frequencies is narrower.

Los Alamos is not too far from where Dr. B's lab is being set up so maybe he will be in contact with Nebel and Park.

A version of the Park/Nebel paper in big type with large graphs

http://www.aps.org/meetings/unit/dpp/vp ... d/park.pdf

Some more interesting abstracts (combined into one big pdf) on IEC and other stuff. Scroll around:

http://nnp03.lanl.gov/pdffiles/thursPoster.pdf

POPS prospects in 1998:

http://fti.neep.wisc.edu/tofeprogram/pd ... 562339.pdf

MSimon
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Postby MSimon » Tue Sep 04, 2007 5:35 am



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