Recovery.Gov Project Tracker

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

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ladajo
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Post by ladajo »

I am not sure about that Kite. I think this is primarily a plus up in time and money for WB8 work.
It has not yet posted to FPDS, so it is hard to tell for sure from our public perspective.

To clarify on some of the above comments, NAWC is merely the contracting agent for ONR in this. The work is not being done for NAVAIR, it is for ONR. ONR is just using the China Lake contracting office to manage the admin for them.

Baed on the wording, I think when they say 4-5 years, that is for power production.
Say less than 2 years to complete WB8 and possibly 8.1. Even if 8.1 is tried, that does not mean they could not parallel pursue a DD power unit, as at that point, DD is proven. So if they are done with 8/8.1 in the next two years, that still leaves 3 years to build a power unit. The bigger question is how well could they pull together energy collection in that time window to capture something useful from the core?

If all goes well, they should be starting on the build of the first "installable" unit in 5 years. As stated, that gives up to 2 years to complete 8/8.1 testing. And 3 years to build and test a full size test unit. Seems reasonable if things stay on track.
Electron injection seems to be a slow down for now, albeit accounted for at this point contracting wise.

I would also point out that $5 Million is $277,000 per month in operating costs for 18 months. Last we heard they are staffing at about 14ish, and that is probably running about $77K/month. That leaves taxes, physical overhead (2 shops rented + services), as well as consumables and material costs for the remaingin $200K. That seems thin, especially if they are buying some hardware with the money. I am sure given a little thought we can break out some better cost estimates to get a feel for the new timeline v. funding curve.
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)

Tom Ligon
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Post by Tom Ligon »

Back when we were looking for a spot more suitable than NASASpaceFlight.com, participants attempted to start up their own. One was the fellow who got me invited to speak at the 2007 ISDC, Mitchell James. He's taking a sort of Prometheus Fusion approach in his garage, although I expect it is less well funded.

While I was back at EMC2 I ran into a few interesting papers suggesting carbon, in the form of diamond films or carbon nanotubes, could be coaxed into copious electron emission. Mitchell recently informed me he has that working pretty well.

If you can eliminate heated cathodes you have the potential to circumvent several problems. The most obvious is that light emission from them is a pain when you are trying to measure light from the plasma. The second is that the spikes of gas pressure these systems are prone to tend to deactivate cathodes ... the rush of ion bombardment blows off the thin active layer, often some low work function dopant such as barium or strontium. Cold carbon may get around these.

http://www.nuclearfusionpower.us/blog/

mvanwink5
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Post by mvanwink5 »

Ladajo,
Factor in ss, insurance, unemployment, contract supervision (+admin charges) by the Navy, etc, it is a wonder there is money left for doing any testing.
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

rcain
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Post by rcain »

mvanwink5 wrote:...
I think this was brought up before, but Bussard wanted to go to the demonstration machine because of potential trouble in pushing electrons into the WB. In a larger machine, the electrons will predominantly come from the ionization of fuel. So, EMC2 is having to solve problems for the smaller machine that won't be relevant for the larger machine. At least that is my thought on this issue...
that was my understanding also. Jeeze... wish they'd just build a full size machine and be done with it. We'll all be dead by the time this thing flies.
Tom Ligon wrote:Way back in the early 90's they thought there would be two ways to build a wiffle-ball. One was to inject the electrons and then build up the magnetic field. That's not the easiest power control problem but it certainly can be done and is an option.
IIRC, isn't that the method described in Doc Bussard's Valencia paper?

In general though, sounds very positive that they are continuing with the project. Time for some catch-up effort by others.

Tom Ligon
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Post by Tom Ligon »

RCain, it is one of the two methods described in that paper and several others.

http://www.askmar.com/ConferenceNotes/2 ... 0Paper.pdf

Look to Figure 16 and the associated text.

What we generally tried was the method of establishing a constant B and ramping up electron drive voltage and thus current. You generally have some control over drive voltage, whereas magnet current is simply switched on at full strength from a battery bank and contactor.

The second method would be to turn on the e-beam straight to the Child-Langmuir current limit and ramp up the B-field. Considering you are dealing with 100's or even 1000's of amps, that's a do-able but considerably more challenging engineering problem.

And I'm not sure WB6 could manage either ... it simply dumped high voltage from a capacitor bank in to an already powered-up magrid. Any ramping up of current would be very rapid and a function of some inherent feature such as series inductance to the HV supply.

ladajo
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Post by ladajo »

The highest value that can be reached by electron density is when this ratio equals unity; further density increases simply “blow out“ the escape hole in each cusp. And, low values of this parameter prevent the attainment of cusp confinement, leaving only Gmr, mirror trapping. When beta = unity is achieved, it is possible to greatly increase trapped electron density by modest increase in B field strength, for given current drive.
So this means that B=1 is when for a given B level, any further increase in drive will just pump e-(s) out the cusps as the B field has not the strength to contain them. Thus, to push the device into high containment, one sets a drive level, ramps up B Field until e- cusp leakage takes its big dive. Then, to set the Wiffleball effect, you ramp up B Field a bit more and squeeze the cusps shut further.

The other tenant seems to be that Bussard 'unveiled' that you will never cut off e- cusp leakage completely, but that with the machine properly constructed, those e- are available to "recirculate / oscillate" back into the machine core.

So as Tom pointed out, Bussard argued that you could go constant I, and ramp up B, or... you could go Constant B and ramp up I.

it would seem that by machine design (also again pointed out by Tom), that B is constant, given the cap bank nature of the coil power supplies, they are on or off, so the more controllabel would be the e- source. Of course another issue for the coils is length of run heating, even if you had a big enough variable power supply to ramp the coils up with for dial-a-field.
There surely are some big-ass DC drives that could feed the monster, however, they would at the same time cook the monster.

Also, we can also return to Bussard's argument on just going big:

Thermal coil heating in smaller machines is the largest issue for acceptable B-fields, and...
It is thus NOT POSSIBLE to test at steady-state ALL of the physics working in concert, in a Polywell machine, in devices below about 1.5 m in size/radius. This fundamental fact, driven by the realities of mechanical and thermal engineering design and construction - to meet immutable constraints of the basic physics -, has made it impossible to reach the objective of a break-even fusion power machine at the sizes and scales used in the U.S.Navy IEF program conducted by EMC2 since 1991. To achieve this objective, it has now been conclusively proven that machines
in this larger size range must be used.
And as a side note, in case Joseph reads this:
The last tests of WB-6 were conducted hastily during October/November 2005. These proved (by beta=one tests) to be an order of magnitude better in effective e-losses (i.e. losses greatly reduced) than WB-4.
As the neutral gas filled the machine interior, fast injected electrons created ionization in this gas. The ion and electron densities produced by this fast ionization were too low to drive the system to the electron beta=one condition.
However, the low energy electrons resulting from this ionization rapidly cascaded with additional neutral atoms, being driven by electron/electron collisions with the incoming injected fast electrons, and made still more low energy electrons. The cascade time e-folds at a rate of 1/(no)(sigmaizn)(veo), where (no) is neutral density, (sigmaizn) is ionization cross-section for low energy electrons at speed (veo). Typically, for no = 1E13 /cm3 (i.e. ptorr = 3E-4 torr), veo = 1E9 cm/sec (Ee = 100 eV), and
sigmaizn = 1E-16 cm2, the cascade e- folds with a time constant of about 1E-6 sec (one usec). Thus all of the neutral gas is ionized and the system is filled with low energy electrons in only a few usec. Wiffle Ball trapping
works very effectively here. If all the electrons were still at ca. 100 eV, the surface beta would be about beta = 0.01, at B= 1000 G.
However, the low energy electrons are heated by fast collisions with incoming fast injected electrons. The Coulomb energy exchange time for this process is also about 1 usec. Thus the device will reach beta = one conditions when the mean electron energy is about 2.5 keV, in ca. 20
usec. Beyond this point excess electron density will be driven out beyond the beta = one limit; the field will have expanded as far as it can within MHD stability limits.
This process uses “cold“ electrons to start, with “hot“
electrons as drives, to yield a beta = one population of “hot“
electrons. Of course, while the terms —cold“ and hot“ imply
Maxwellian temperature distributions, these systems do not
exhibit this on the time scales of interest. This is called the
“two-color“ electron startup mode, and will work for any
machine which is e- driven and supplied with neutral gas
input at the proper rate. This is the preferred method of
startup for reactor-scale systems
.
The overall result is that a deep potential well is provided in
a few tens of usec, and the ions formed by ionization are
trapped within this well, heated by the fast e- injection to
well depth energy, and thus yielding fusion.
Of course, for the steady-state operation of the basic concept,
what is needed are large controllable power supplies, much larger machines (but still only to about a maximum size of 2m radius), and controllable gas supplies and e-guns able to survive their B and E fields and gradient environments.
With these the machines can be driven initially via internal neutral gas burnout, and can use the “two-color“ electron energy/density method (which has been known since 1994) to drive startup. As described above, this two-color effect (starting with “dense “cold“ electrons and transitioning very rapidly to less dense “hot“ electrons, by energy exchange collisions with incoming injected electrons) will occur automatically in any machine, as employed in the pulsed cap-driven tests of WB-4 and WB-6, if background neutral gas is used by fast electron injection as a source for initial ionization within the machine.
Go big or go home.
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)

choff
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Post by choff »

There's a small update at NextBigFuture.
CHoff

Roger
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Post by Roger »

Robthebob wrote:They have problems pumping electrons into the system? Their electron gun isnt big enough? that just sounds weird to the point that it's almost funny. Just if they know what well depth they're going to try to get, they should know around what type of drive voltage the gun need to be able to have....
Is this the anomaly previously mentioned, maybe e-guns were to close to the Mgrid? Pull them back a bit, increase power a tad?
I like the p-B11 resonance peak at 50 KV acceleration. In2 years we'll know.

ladajo
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Post by ladajo »

Bussard seemed to think that in smaller pulsed machines that the more aggressive you got with the machine that timing and cooling became more problematic. To the point that you couldn't do it with a small scale machine, especially considering time, cost and fidelity as compared to just going big.

It really makes sense when you think about it. You are trying to spin up wiffleball, which by its nature limits e- pass through at the same time you are trying to drive in e- to build the well depth you seek. All of this in a "shot" based machine.

Can't run the magnets to long cause you will cook them. Can't run the e-guns long cause you don't have a big enough power supply to get what you want. And you are trying to time it all so that you get enough e- in to build the well, and press out on the magnetic fields to achieve Beta=1, which in turn reduces access to drive in e-(s) as the wiffleball forms. It really would be easier to deal with in a larger scale cooled coil machine where you can get a true steady state run with real knob turning, instead of shot based tests. Set, fire, record. Set, fire, record.

As Bussard himself said, to see it all really work together, you need to go big. Testing to date has reportedly looked at facets. And the sum of the facets is good, but limited in context. Once they get the shot settings 'right', they then fire for effect and count neutrons. But, there is no tweaking. What comes out is a result of what was loaded.
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)

bennmann
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Post by bennmann »

Oh Glorious day, 5 mil!

The e gun stuff is very interesting. PERHAPS Nebel and Park started a new team that is black that we don't know about, and they are working on the big machine while EMC2 still keeps a small profile trying to make the smaller machines more viable with the e-gun because space is a premium in the navy. Of course there's no evidence for that. But the smaller machines logic does still make sense to me, and this contract is bigger than the last one.

MSimon
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Post by MSimon »

I was looking at a paper on electron guns for a similar machine several years back and if they did the math right the curves show the amount of drive necessary declining with an increase in machine size.

I can see the curve in my mind but I don't recall exactly the numbers but IIRC the drive levels went down orders of magnitude with linear increases in size.
Engineering is the art of making what you want from what you can get at a profit.

Mike_P
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Post by Mike_P »

Hi all,

I had an interesting discussion with someone who had 30 years experience in contract administration with the Navy, in particular, contracts with NAWC. Their opinion was that NAWC is the customer not the ONR. ONR might be supplying the dollars but NAWC is definitely the customer. One other thing they pointed out was that if power supply was to be used for propulsion then Nemesis would have been the customer not NAWC. Lastly, if NAWC is involved then the final use for the power must be airborne. If so then going big is not an option, sorry Ladajo. The only real use for an energy source of that magnitude in an aircraft would be for an airbourne laser weapon. Large pulsed discharges of power would be great for such a weapon.

If this fairy tale of mine is close to being correct then it would explain why they haven't gone large and are instead focusing ( pun unintended) on working through the issues of having a small light weight reactor.
Eschew Obfuscation or at least "Push the button, Max!"

ladajo
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Post by ladajo »

It really is ONR's project. They are the sponser and shot callers.
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)

RobL
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Post by RobL »

I am sure that most of you have heard of Kelly Johnson, Head of Skunk works and IMHO one of greatest engineers in history. He had a set of 14 written rules for running projects and a 15th rule that he passed on by word of mouth:

"Starve before doing business with the damned Navy. They don't know what the hell they want and will drive you up a wall before they break either your heart or a more exposed part of your anatomy."

tomclarke
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Post by tomclarke »

Mike_P wrote:Hi all,

I had an interesting discussion with someone who had 30 years experience in contract administration with the Navy, in particular, contracts with NAWC. Their opinion was that NAWC is the customer not the ONR. ONR might be supplying the dollars but NAWC is definitely the customer. One other thing they pointed out was that if power supply was to be used for propulsion then Nemesis would have been the customer not NAWC. Lastly, if NAWC is involved then the final use for the power must be airborne. If so then going big is not an option, sorry Ladajo. The only real use for an energy source of that magnitude in an aircraft would be for an airbourne laser weapon. Large pulsed discharges of power would be great for such a weapon.

If this fairy tale of mine is close to being correct then it would explain why they haven't gone large and are instead focusing ( pun unintended) on working through the issues of having a small light weight reactor.
Well it is an interesting idea. I suppose you might market Polywell as an efficient way of attaining very high pulse energies even though overall energy gain not high enough to use as a continuous power source? But that would be more true of lower containment time fusion systems.

Edit - I'm not sure you could ever get better pulse Q than continuous, but eqpt would be easier.
Last edited by tomclarke on Sun May 13, 2012 4:58 pm, edited 2 times in total.

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