Archived - Example of magnet effects on plasma

[Dan Tibbets]

Something to do with surplus magnets harvested from microwave ovens.
I mounted 6 donut shaped magnets in a cube, similar to a Polywell to see what it would do to the plasma appearance in my Pressure Coooker demo fusor.
It shows the limited 'confinement' of this low energy plasma. Also, it shows the unfortionate interception of the plasma by the North pole of the magnets on the inner face of these permanate magnets. To avoid this, I would have to use electromagnets or glue a bunch of disk magnets end to end to form a ring (?).



Dan Tibbets

[MSimon]

Outstanding bit of work on the cheap!

[tligon]

Ah, an improved WB1! You spaced them out, like WB-6!

I've hoped for several years one of you guys would try this. I have six larger donut magnets in the garage I was thinking of trying this with.

Yes, you need electromagnets to avoid the face cusp losses, which brings in a whole issue of floating high current power supplies (the easy answer is car batteries). All "solid state" magnets will have B field lines going into the faces at some point. You could try ceramic insulators, but my bet is they'll just encourage recombination. All the WB experiments in which insulators were tried at cusps produced fireworks there.

I know at least one amateur working with high-temperature superconductors, but he is not doing electrodynamic fusion. With such a machine, a Polywell made of a single turn of conductor might work, similar to the copper tube machines (MPG). LN2-cooled copper tube has also been suggested.

[Chris Bradley]

(Are Halbach cylinder type magnets used in microwaves?)

I would be cautious over loose use of the words 'confinement' and 'plasma' in this set-up, though I know you understand the difference I am not sure others may. This is a gas discharge whose particle motions are being modified by magnetic fields.

It does look to me like the ceramic magnets have charged up and are doing a job of reflecting the ions back. I had wondered if this could be done and was due to try it myself. Nice to see it.

I am not sure it is *much* of an improvement over WBx... it would appear to me to be a quantum leap forward !! At least you can see some sort of structure in the ion flows, more than can be said for any other image I've seen of a WB!

D'you think you have enough control over pressure to get equivalent current ratings between with- and without- magnet experiments? I'd be interested to know if the magnets slow down electron conduction in this arrangement.

[Dan Tibbets]

From Chris Bradley: "I would be cautious over loose use of the words 'confinement' and 'plasma' in this set-up, though I know you understand the difference I am not sure others may. This is a gas discharge whose particle motions are being modified by magnetic fields."

You might be giving me more credit than I deserve. Unless plasma is more accuratly described as a population of atoms that are All ionized, while a gas (glow) discharge represents a population in which perhaps only a small percentage is ionized at any given time. Or, to use a water analogy and steped down one phase: plasma= steam, and gas discharge = boiling water.


Dan Tibbets

[Mike Beauford]

Very nice work indeed! Keep up the great work!

[Richard Hull]

Nice piece of simple experimental work. It deserves achive status. Many thanks for this effort and visual posting.

Anyone dare to see about real fusion results in this type arrangement? It is obviously not ideal and not a WB by any stretch, but very interesting.

I know, I spent many a delightful hour with various magnet structure arrangments in the long two year fusor I and fusor II periods 97-98. I then put the magnets away and went and did IECF fusion.

Cool stuff and interesting images, but where is it in the advance of fusion in our systems?

Richard Hull

[Chris Bradley]

Richard Hull wrote:
> It is obviously...not a WB by any stretch

Out of interest, what would be your definition of 'being a WB'? What qualifies a thing for that title?

[Carl Willis]

Very pretty discharge, Dan.

Do you have plans for graduating to better vacuum equipment than the pressure cooker soon? It looks like you're at a torr or more of pressure.

In regard to whether Dan's magnetic trap should be associated with the terms "wiffle ball," or "Polywell," I agree with Richard. "Wiffle ball" applies to an effect in magnetic-mirror traps in which electron currents do particular things to the magnetic field. It's unclear to me that this trap's design and operation is consistent with creating that particular effect. There is also no electric field surrounding the magnets that would act to trap escaped electrons, and a negatively-biased central grid is in use rather than a confined-electron space charge, so this is a different animal than what Bussard, Rick Nebel, et. al. set out to do. Generally speaking, I think we need to exercise restraint in the use of vocabulary specifically associated with the EMC2 effort. The jargon has popular appeal but the concepts are widely misunderstood. I also worry that "chumming the waters" with this lingo, even if it may be technically appropriate, will draw out another round of EMC2 sycophancy. Personal opinion, for what it's worth.

-Carl

[Chris Bradley]

Carl Willis wrote:
> "Wiffle ball" applies to an effect in magnetic-mirror traps in which electron currents do particular things to the magnetic field.

So in this device of Dan's, not a single electron is trapped by, nor reacts with, magnetic mirrors, yet such effects have been demonstrated with calibrated diagnostics in EMC2's experiments?

I'm just interested in a definition because without it we'd never be able to determine if an 'amateur' has actually reproduced a 'Polywell' effect, and found it 'successful' or 'wanting' in the process. We might have to include within the definition of a Polywell/WB "..a device evolved from, and built by, EMC2.." which would, by definition, exclude the possiblilty of an amateur effort. If an additional element (in this case an additional recirculation grid) is also not permissible within such a definition, then we may find that such a definition also excludes future "WB's" from being WB's, if there are minor changes introduced!!

[Richard Hull]

Carl's discussion carried a condensed definition for me, however, the true definition is to be found in Bussard's written works.

The whole WB concept is designed to increase fusion. For my money, anyone who uses magnets in a WB configuration or what they want to call a WB configuration that increases fusion in a fusor system using the exact same energy input as with a simple fusor will be an advance. I don't mind a simple internal permanent magnet arrangement that is cheap improving fusion. Anyone can do that.

Can it boost fusion, though?

No one knows because no one has ever done it!

To my direct knowledge no one has used any WB device including Nebel and Bussard to do any fusion!!! There are no images or measuring devices of any sufficiency presented as evidence of fusion during any WB run. There are folks telling us they have seen it or done it. But the stripe of proof is missing. Data is missing.... Sorta' key to the effort and getting others to believe in it.

As you all know, we, at a minimum, demand some images and proof of fusion read by accepted instruments to allow induction in the Neutron club.

It is a good thing that Nebel's group is professional and not amateur for they couldn't get into the neutron club here as amateurs with their currently presented material.

Richard Hull

[Chris Bradley]

Richard Hull wrote:
> The whole WB concept is designed to increase fusion.
> To my direct knowledge no one has used any WB device including Nebel and Bussard to do any fusion!!!
> As you all know, we, at a minimum, demand some images and proof of fusion to allow induction in the Neutron club. It is a good thing that Nebels group is professional and not amateur for they couldn't get into the neutron club here as amateurs with their currently presented material.

I remain unclear, then, why Dan's efforts are "obviously not ... a WB ", whereas EMC2's devices are WB's!?

It doesn't have neutrons just as the official WB's don't. It's your "obviously not ... a WB " comment that I'm probing, not the concept of the Polywell.

[Wilfried Heil]

Dan,

good images and I like the near zero-budget approach. If you can't create a "deep potential well" with trapped electrons, at least you can simulate that by placing the cathode in the middle of the magnet assembly.

I too wonder why the plasma touches your magnets at several points and not along a straight line. Do these have several poles? Is this really an effect of the magnets or just of the mechanical baffle in the way of the glow discharge?

Not bad at all!

Wilfried

[Carl Willis]

Hi Chris,

>So in this device of Dan's, not a single electron is trapped by, nor reacts with, magnetic mirrors, yet such effects have been demonstrated with calibrated diagnostics in EMC2's experiments?

Is this an inference from something I wrote? (I don't think so.) Is it a rhetorical point?

I suspect most readers can accept, prima facie, that there are a plurality of electrons in the discharge in Dan's pressure cooker; that there are magnets in the pressure cooker configured as a magnetic-mirror trap; and that therefore at least some non-zero number of electrons will indeed be trapped to some degree (where trapping means that they are reflected toward the interior by interaction with the magnetic fields in a widely-known manner instead of moving away from the negative-charged object in the interior as they would tend to do in the absence of those magnetic fields). In responding to this I feel like I'm a lawyer being compelled to make a case that the sky is blue.

About Wiffle Ball and Polywell. While wading through this invented jargon, a certain children's poem called "Eletelephony" comes to mind...anyone else? Really I don't care what people call things--let the lawyers sort it out. If I had a point earlier, it was that Dan's apparatus differs from Robert Bussard's apparatus, and that caution would be recommended in applying Bussard's invented vocab to Dan's apparatus. I think Dan is doing interesting things of his own, and describing his magnets as a magnetic-mirror trap is the better approach. It's established, it's accurate, and it comes with none of the social flypaper effect that the Bussard jargon does.

-Carl

[Chris Bradley]

Carl Willis wrote:
> If I had a point earlier, it was that Dan's apparatus differs from Robert Bussard's apparatus

..and if I had a question earlier, it was "in what particular way does it differ"?

What unique, singular (or set of) difference(s) does it have to Robert Bussard's apparatus?

OK, permanent magnets and a grid at the centre. The permanent magnets merely, potentially, make it more efficient and the grid is 'simply' an experimental substitute to make up for, and give a helping hand to, an electron core not deep enough by magnetic fields alone - which could reasonably be argued to be an experimental stepwise investigation to create a neutron gain (higher ion flux) but with an efficiency loss (ion collisions with grid).

This is no mere lawyers trifle, it is a potential and bonafide discussion on an amateur polywell investigation. If neutrons are detected then the grid could then be reduced progressively to see the function of neutrons produced with grid transparency. In extremis, the grid disappears and it would surely then be a WB? Thus, such a setup could be used as a 'probe' to explore WB functionality. My question is therefore not just bandying with words, but if this sequence of events is followed, then *would you end up with a 'full on' Polywell*?

I don't know what a 'full-on' polywell means, but Richard and yourself seem to have an idea, hence this legitimate question and the probing of the generalisation "obviously not a WB". Once the differences are properly identified, then we will know the answer to this last question.

[Dan Tibbets]

OK, using the term 'Polywell wannabe' may be a stretch. Other than taking an oppertunity to take some pretty pictures, I was curious if the flawed magnets(solid state magnets with face cusps instead of electromagnets without face cusps) could show some visual Wiffleball effects as the voltage (electron pressure?) was increased. Perhaps the plasma (glow) border pushed out closer to the magnet surface with increased voltage a little bit (perhaps wishfull optical dilusion as the plasma brightened alot with increased voltage/ current). I could not appreciate any obvous changes in the geometry, or shapes of the cusps. If there had been profound changes in the appearance in this extreamly sloppy setup, I could have exclaimed "Eureka"! Alas, no such luck.
If I cleaned up the construction- moved magnets closer together so that the gaps were closer to what they are susposed to be, made things symetrical, etc. the results might be a little more meaningfull. But, after a few runs my bailing wire has already softened, and sags. So I'll have to redesign the magnet cage. The microwave magnets are perhaps to thick. Perhaps using thinner ring magnets, like those on speakers would work better.

Concering Chris Bradley's question about current and voltage variations without and with the magnets- The measured voltages tended to be ~ 10% higher (at the same Variac input voltage) and the current ~ 10% less when the magnets were present. I am without a deep vacuum gauge since I fried the prevous one. So the comparable vacuums between the two setups were only grossly similar. I used ~ the same pump down time for both (~15-20 min.). Assumeing the magnets, hot melt glue, etc were not outgassing much the pressures should have been in the neighborhood of ~ 150-300 microns (based on prevous experiance). At least the voltage/ current loads did not obvously worsen with the magnets present.

And, another picture below.


ps: the magnets were not grounded. They were floated- so were they at the voltage of the cathode?, somewhere in the middle?


Dan Tibbets

[Carl Willis]

>What unique, singular (or set of) difference(s) does it have to Robert Bussard's apparatus?

I thought I already commented on that.

viewtopic.php?f=18&t=7816#p56455

>There is also no electric field surrounding the magnets that would act to trap escaped electrons, and a negatively-biased central grid is in use rather than a confined-electron space charge, so this is a different animal [...]

It's a fundamentally different animal. It doesn't have electrostatic confinement of electrons. It has a cathode grid. The permanent magnet flux thing that Tom Ligon mentioned is more of a disadvantage of permanent magnets in this use than a fundamental difference, but whatever.

-Carl

[Richard Hester]

For a bit, I was all gung-ho to do a small Polywell using a 6" (silly me, I mis-typed 6' before) sphere with side arms in a tetrahedral or cubical arrangement. The plan was to stack large donut magnets on the side tubes to make the cusp fields and shoot electrons down though the tubes. I had bought the hemisphere and flanges and magnets and...

My enthusiasm was dampened in a hurry by Bussard's Google talk pretty much spelling out what would work and what wouldn't. In retrosopect, this still may be an interesting experiment to try to in order to investigate well formation on the cheap (relatively speaking), even given that there will be essentially zero recirculation. The way I figure it, the efficiency would be no worse than a standard fusor. With the magnets on the outside, the walls are taking the beating from the electrons, not the magnets, and the walls can be cooled from the outside.
Doing it up right would require a big, big vacuum chamber with electromagnets (not a good match for my basement or my wallet). However, with that in mind, I recall a gas station in town that had a spherical propane tank about 8' high, and i used to muse about making a big, big fusor with it (this was back in '99 or 2000). That tank would would have made a wonderful chamber for Polywell experiments, if I could gotten it before it got all stunk up by the propane (the walls drink up a tremendous amount of the odorant used so that you can smell a leak).

I was thinking of using a CVC piezoelectric puffer valve (millisecond response time) to inject measued amounts of gas.

[Chris Bradley]

Carl Willis wrote:
> There is also no electric field surrounding the magnets that would act to trap escaped electrons

'no' electric field? I am not sure if we (can) know to what degree these magnets have charged up.
(I guess a 'wrap' of foil held to some desired potential could fix the field to some desired magnitude.)

Carl Willis [then] wrote:
> at least some non-zero number of electrons will indeed be trapped to some degree

The quantitative delta between what Bussard intended and what is likely to be going on in Dan's device is not in question. For sure in this current trim it falls far behind the intent, surely by many orders of magnitude. But this is not to prove that WB-1 through X successfully trap electrons any more successfully either, yet these *are* WB devices? So, *obviously*, factual proof of successful and significant electron trapping is not a prerequisite of being defined as a Polywell/WB device!

You may have expressed a dislike for lawyer-ese, but I would congratulate you on your ability to dodge being nailed down to concluding a hard statement of things, just as per their own mastery of such verbal techniques!

[MSimon]

The difference between this device and a Polywell are two and they are significant.

1. Permanent magnets. They will have a plasma burn where the field gradient is zero (at the pole faces). Thus high electron/ion losses precluding wiffle ball formation.

2. The magnets have no definite charge.

The device seems to me to be a good one for visualizing cusp losses by watching actual plasma flows. Other than that its differences from a Pollywell are so great that further conclusions are unwarranted.

[MSimon]

I did some BOE calculations and figured a small voice coil operated valve could work if you could keep it sufficiently shielded from the magnet/electromagnet fields. Good operating force and response times in the sub mS range. If you tied it in with a pressure sensor of the appropriate speed you could servo the gas pressure so puffing would not be required (assuming a continuous operation machine). For pulse operation a puff valve is probably better.

Any way if you are interested contact me.

[tligon]

I would classify it as a WB because it is a similar configuration to WB1.

That is not to say it is actually capable of making a true "WiffleBall" (one word to distinguish it from the trademarked toys). It almost certainly does not confine electrons well enough to create a diamagnetic wiffleball. OTOH, I'm not sure that phenomenon has ever been conclusively demonstrated in any of the electromagnetic WB machines.

Dan's gizmo does produce very similar plasma effects to those seen in WB1 and WB2.

[tligon]

Did Dan report his operating pressures?

I did not run WB1, but it ran in the same chamber as WB2, which I did operate.

The chamber was equipped with both a small turbopump (typically used for the experiments) and a large ion pump. It was quite capable of high vacuum operation.

Both experiments used commercially-available dispenser cathodes, which are easily poisoned or inactivated by high pressure (1e-3 torr would kill 'em). Typically we lit off WB2 at around 1e-6 torr, and the pressure would then shoot up to around 3e-4 (or so says the caption of the picture hanging above my desk here). The glows produced by WB1 were comparable. That intense glow does not necessarily indicate pressures as high as a torr.

WB1 differed in one important aspect, which Dan's machine could easily be modified to duplicate. WB1 faced the ceramic (non-conductive) magnets with stainless steel "washers" (preferably 316 or a similarly non-magnetic alloy), held in place by stainless steel welding wire (same stuff we made the DG2 fusor grid from). These provided conductive inner and outer faces, wired to serve as the machine anode.

[Carl Willis]

Hi Chris,

I'm just resistant to having words put in my mouth, whether they be a "hard statement of things" or merely some semantics-related bickering as we have had tonight. I did explain my reasons for why Dan's creation is fundamentally not kin to the device whose vocabulary is getting thrown around. I remain satisfied with what I wrote, and I remain bemused by what you infer from it. The argument is hard to leave behind though...it vaguely evokes the satisfaction of eating billy-goats right off the bridge.

>'no' electric field? I am not sure if we (can) know to what degree these magnets have charged up.

I also noticed Dan's late comment that the magnets are "floating." That update clearly negates anything I said that assumed the magnets sat on the floor of Dan's metal pressure cooker, as they appear to in the photo. If you want credit for the opposite assumption all along, i.e. that the magnets were insulated from the cooker, I don't think anyone would begrudge you that credit.

Apologies to Dan for the noise on his thread.

-Carl

[Chris Bradley]

I'm sure Dan can speak for himself if he objects to the debate. I expect he may well be awaiting the conclusion of the debate to see if further development *would* be considered a WB or not, just as I am. For the reasons I stated above, I considered this is a bonafide question to be asked and debated. (I don't think I have got to 'bickering' status, but it's in my character to get scrappy!)

Why is this significant/of any relevance? Well, to start with there is Richard's and your $400 prize;
viewtopic.php?f=7&t=242#p242
and if you've both already dismissed this as 'not a WB' then it is already concluded that Dan DT cannot win this prize with this device (and I wouldn't put it past his resourcefulness to get that far!), but it has not been stated what particular features are unacceptable.

But we still remain with this "unclassifyable" status of what a 'Polywell' actually is. I remain unclear what the definitive features of a Polywell are such that they include the previous WB's but exclude other devices.

Tom Ligon wrote:
> I would classify it as a WB because it is a similar configuration to WB1.

I consider that authoritative. Thanks, Tom.