Hello from John Duffield

[Farsight]

Hi Doug, John Duffield here. I'm the "relativity+" guy, an amateur with an interest in fundamental physics and education. I followed your link from physicsworld. I see you're into electronics, and I guess you know all about The World's Simplest Fusion Reactor. I've recently start a physics discussion forum myself, sounds like we've got a few things in common.

[Doug Coulter]

Hi John! And Welcome to our little corner of things. Here we are kind of following the open source software model, but with physics and tech stuff, with a big emphasis on practice and actual results, but of course we all like to gas on about theory too -- so there's a place for most anything. If there is something you can't find what looks like a good place, let me know and I'll create it.

The idea is to keep the signal to noise high while allowing people to do what they want -- both. So far, it seems to be working decently well, but I'm all ears on how to make it better.
We are trying to combine the "many eyes" feature of big science, with the "turn on a dime" feature of individuals who can do whatever the heck they want to right now. With luck, the best of both, and we all help and are helped, so good for all -- you get to use my work, I get to use yours. If I improve on yours, I contribute the improvements back the the community in a happy loop.

Go ahead and give us a link to your forum, we're not competing with anyone here (that I know of). I'm just trying to fill a need I perceived that wasn't filled before. Luckily we have a good number of members here I consider "heavy hitters", but sadly, they don't post as much as I'd wish....you know how that goes, I'm sure. I'll have to go around and rag on them some and see if I can get some more action out of them -- most of the current members are people I invited because I knew them and their work already and have a lot of respect for.

We are very much trying to "write the book" here on the things one doesn't generally learn in formal education (we assume people have some education already, whether formal or otherwise, or they'd' not understand the bulk of this anyway).

How the guys who make things actually work, do it. With a nice side order of why they do it the way they do, rather than some other way they've found doesn't work out as well. That's a huge time-saver for those just coming along, so failed ideas (and why they failed) are important here too. Sometimes the "tricks of the trade" are as important as the next neat theory.
Combined, unbeatable.

BTW, this has turned into a [urlhttp://www.coultersmithing.com/forums/viewtopic.php?f=40&t=130]hilarious discussion[/url]. I'm rolling. Amazing how many people know almost enough to have something to say. Maybe I shouldn't have instigated it (that place is normally pretty dead), but it sure is fun. As to the argument that antimatter has positive energy, and therefore mass, I'd have to agree, because I can't somehow visualize exactly what "negative energy" would be. I'm no so sure about there being no such thing as anti-light -- how would we know?
Maybe assuming that breaks something we know is true, but I'm not up enough on the various TOE's to say what that would be, myself. Sounds like it would be one heck of a hard thing to test, anyway.

I do remember one interesting argument from the days when people used the word Tachyon. That is that if something had negative mass, it would have to go faster than light, so C is an unreachable speed from either direction, so to speak. That one stuck with me somehow, not that I believe in negative mass (or for that matter, dark energy or dark matter -- smells like what a software guy would call a kludge-patch on something that doesn't really fix the underlying issues at all but simply hides them at best -- inelegant, therefore unlikely to be true, despite what we think we see). Doesn't mean I'm going to go off on MOND either -- same reason.

I'll defer to anyone who can convince me they have a clue what they are talking about, though. I'm a pretty good skeptic.

[Farsight]

Thanks Doug. I can't advise on how to make it better, I was hoping I could pick up a few tips from you actually. I like your ethos wherein one takes the best of big science and individual endeavour. Not that the two are the best of bedfellows, but I think it's important to be hands-on. I talk to experimentalists, and I've got various bits of kit in the garage. But with a two-your-old, I also have a reticence, such is life. This is the physics discussion forum. I've started small, with a few invitees, and I'm taking it slowly in case I find issues. We'll see how it goes.

Your hilarious discussion is maybe the wrong link. That's your First Hands-free fusor runs thread, where you're giving technical details. I guess you mean http://physicsworld.com/cws/article/news/44343 re antimatter falling up. Methinks you might have an interest in vacuum impedance and the evanescent wave. I don't believe in negative mass either, and I'd hazard a guess that I'm even more skeptical than you. Yes, there are issues with dark matter, particularly in the guise of WIMPs. But it isn't all bad news. Space has its vacuum energy, and since it isn't going past you at c, this has a mass-equivalence. And don't forget: space is dark.

[Doug Coulter]

You're right about the link, thanks for fixing that one for me, I'll just leave the wrong one there for the moment.
I can't add much in the way of tips, other than it pays to be computer facile, have another reason to have it on anyway, and be able to type like the wind. At that I probably post far too much here for balance, but I'm hoping members will eventually swamp that out. After all, I have decades of cool things I've done to catch up with -- but so do many of them. This is going to get big, and I'm glad I got the unlimited BW and bytes plan at my ISP for it, locked in a good price along the way by a multi year contract.

I can't imagine doing this with children (or not very responsible adults) around, a two year old is a real terror! I have signs up, like "excessively dangerous thing, don't even think about it" and "don't look at this with remaining eye" but you know how that goes. I kind of have to give a little orientation lecture at the lab door for new visitors -- I don't have the room to make it all walled off and somehow "safe" from idiots, so the only way is to keep them out.

I forget which insight that "space is dark" thing proves, but I remember going "ohhhhh" when I first heard it.

On a much more practical note than "things falling up" I have a question for anyone here that knows some theory. DD can take three reaction paths, the first two about equal probality, one of which makes neutrons, and the last one that goes to pure gamma rays and a lot more energy (16 Mev). Those numbers were of course derived from measurements in a thermal plasma.

Is there any hope/possibility that in a non-thermal plasma that something like polarization might allow one to have a shot at changing the probabilities of the three reaction paths?

I am more than willing to go beam on beam (no electrons), and use RF, lasers etc to get to a place that would allow that.

I'm only doing DD now because hey, it's easy, and the neutrons are a nice way to prove fusion is happening at all, but I'm no fan of free neutrons in my lab, activating things (including me).
So you can see the interest in that, not to mention about 4x more energy output. As it is, every time we get to multiple millions neutrons per second, we scale down again to stay in some sort of safe exposure range, and it's getting harder to do that as things get better, so we're also shortening run times.

[Farsight]

Sounds good Doug. Unfortunately in my case when it comes to high voltage and big amperages I fear I might turn out to be the idiot, if you catch my drift.

I have a question for anyone here that knows some theory. DD can take three reaction paths, the first two about equal probality, one of which makes neutrons, and the last one that goes to pure gamma rays and a lot more energy (16 Mev). Those numbers were of course derived from measurements in a thermal plasma.

I don't know about this I'm afraid. I know that fusion is doable on a benchtop, but that's about it for me. As far as I know without "hot" particles, you need pressure instead, and there's a sliding scale. Something like the way you can do arc welding of metal with blue heat, blacksmith welding with red heat and hammering, or cold welding with no heat and a lot of pressure. I'll ask a guy about it, see if he knows.

[Doug Coulter]

Right -- it would take around a megavolt of "pressure" to actually push two D'+s together against Coulomb forces, we are getting some fusion via quantum tunneling at voltages as low as 20kv, but of course it goes up fast with input energy -- all the way till the point where you get no net gain and beyond (no low energy cross section sharp resonance in this one, as there is in DT).

Some data of fusion reactions

This is from an astrophysics book, and assumes a thermal situation -- everything random -- but S(o) is a sort of measure of cross section probabilities.

I think thermal is :
A. Not the way to go, too much random loss and so on, and
B. Already being done as well as it's going to be by the tokomak boys, or perhaps the DPF guys.
C. Leaves electrons in the mix, and they are notorious for radiating loss energy as photons.

I do plan to do a DPF or pinch machine soon, I've got the Maxwell caps of the requisite thousands of joules to do it.
But that's for fun, I really don't expect anything that is basically a thermal/pressure thing to work out at any human scale, and so far, I'm right, no one is doing all that well that way. Nice as a lab source of neutrons, but that's about it. Even beam on target DT beats those, though for efficiency even without the center mass (conservation of momentum) working for you. And with target stationary in the lab frame, has a big resonance at a mere 110 kv, less if you do beam on beam of course.

What I am wanting to do is something more coherent -- head on collisions, beam on beam, no energy put into degrees of freedom that don't help me. Fusors kinda/almost do that now, but of course there are other issues with them. I can easily build a beam on beam device that gets rid of most of those troubles, however, and one is in (slow) progress for down the road. See this thread for some papers on an interesting way to do a beam on beam within the same ring. Looks very doable (and I have the right reamer to make the cones from). All you'd have to add to the fancier ring would be some stuff to re-bunch the beams, and some focus at the interaction points. This thing can support two counter rotating beams at a time, for example -- pretty simple too.

ChrisB here has a patent on something that solves most of these problems in a different way than I contemplate, it's a cool idea and I hope he posts the patent up here soon.
He has found a way to redirect and re bunch scattered particles from near misses with energy efficiency for example, eliminating the thermalization problems.


However, I have to believe that the orientation of the nuclei when they approach one another matters to this -- spin too, and spin axis, and that in a low current beam, all these things can be controlled via various tricks. The question really is -- is that worth it, potentially? If we could alter the rates of the 3 reactions in a way favorable to us, or could we make all 3 more likely than they are in a random-thermal enviornment. We already know the sun is a pretty lousy fusion device -- it's been around awhile and it's very inefficient per gram as a power source, just has a lotta grams. Of course, it's not burning pure D as well.

Here I am interested in eliminating the loss sources -- electrons giving off X rays and being accelerated backwards into the tank walls, and avoiding putting energy in to nuclear motion that doesn't result in head on collisions. This question I'm asking is the next twist on things after that. In other words, as non thermal a reaction setup as is possible to create.

DD isnt't the only fuel I am interested in -- I'm no fan of neutrons in general, they make quite a mess of things. For example, p->Li is a good one, the one Cockroft and Walton began with, and has a decent cross section too, at reasonable energies, and nicely high Q, though handing Li as such creates problems -- any that condenses on insulators makes trouble for example. P->B is nice, but needs much higher input energy.

So what I'm looking for is what the crypto boys call a knapsack, or trapdoor -- some slick way to manipulate conditions that affects the tunneling probability into fusion. I have long believed that this is a finesse problem, not to be solved by brute force, as the tokomak guys are trying -- and failing by most standards.

At any rate, this is a potential low hanging fruit -- science kind of moved on to higher energies and subnuclear stuff before this was all even measured, or so it seems from various intense attempts to scan the literature of the day, and since.

[chrismb]

DD can take three reaction paths, the first two about equal probality, one of which makes neutrons, and the last one that goes to pure gamma rays and a lot more energy (16 Mev). Those numbers were of course derived from measurements in a thermal plasma.

As far as I was aware, all fusion cross-sections have been evaluated by beam into stationary targets (gaseous, or otherwise). This is the only way to properly control for random scattering that would otherwise be insolvable by thermal fusions. And the only fusions that have been observed in thermonuclear plasmas to date are DD and DT - again, AFAIK. I don't think that even D3He has been observed yet (except in fusors).

In regards spin-alignment of nucleii, I don't really know. The only time I have seen it discussed is Todd Rider describing the spin-enhanced fusion cross-sections for p-11B, which, by implication, suggests DD doesn't have any such known spin-aligned resonances else I'd have thought he'd have talked about that first?

[Farsight]

I don't know enough about this to contribute usefully Doug. All I have is outline fundamental concepts. It goes something like this: the thermal approach is like me firing a fusillade of lead bullets inside my garage. They're fast, so they're "hot". Sometimes I get lucky and two fall to the ground welded nose-to-nose like civil war battlefield rarities, but it takes a whole heap of input energy for a small output result. I'd say you have to find a way to end up with the equivalent of a hole in a tungsten block into which you drop a pair of bullets. Then you hit them with a hammer and punch. Or a whole array of holes which you spray with a machine gun.

However, I have to believe that the orientation of the nuclei when they approach one another matters to this -- spin too, and spin axis, and that in a low current beam, all these things can be controlled via various tricks. The question really is -- is that worth it, potentially?

Sounds plausible. Think of the bullet analogy. If they're contra-rotating at nose-to-nose impact they're less likely to skitter apart. But IMHO this still isn't "bracing" them. As to how you do this, I don't know, but note that Barium Titanate has a very high magnetic permeability. See http://en.wikipedia.org/wiki/Barium_titanate where it says The addition of inclusions of barium titanate to tin has been shown to produce a bulk material with a higher viscoelastic stiffness than that of diamonds. Barium titanate goes through two phase transitions that change the crystal shape and volume. This phase change leads to composites where the barium titanates have a negative bulk modulus (Young's modulus), meaning that when a force acts on the inclusions, there is displacement in the opposite direction, further stiffening the composite.[3] See that tin? Think soldering, and borax. There's something on google about the dielectric properties of boron incorporated into barium titanate that might be worth looking into, but the first couple are journals that I can't read, and I've got to go. And besides, like I said, I don't know about this field, I'm probably just wasting your time.

[Doug Coulter]

Chris, yep, that's what I thought too. But we know that in beam on target types of things, there's no control over nuclear orientation, and that D does have a moment because it must -- can't be round given what it's made of. I have seen experiments where, like NMR, a big magnet was used to get partial control over this (even with neutrons, which have a kind of moment of their own), but nothing that relates to any fusion cross section. Normal rotational speeds are at any rate, insanely fast if I recall right, around whatever axes the thing can rotate about.

John, John Futter and I've been talking about just such an approach. The thing about the bullet analogy is this -- they're all moving the same way and don't collide with one another doing that!
(which is also the problem with a thermal velocity vector distribution, a lot of the energy you put in doesn't create collisions -- so I'm an a-thermal kinda guy)

However, there is a possibility of using something like silicon as a "funnel" at which you shoot "shotguns" from both sides. In his business (implantation etc for the government in New Zealand) it's a problem as things go much deeper in one of the xtal orientations -- it's like looking down a row of bundled tubings. So to implant to some desired depth, they have to watch that.
That's kind of a sneaky trick to get to better effective luminosity for sure, which is definitely part of the game here. Else I work with space-time bunching. Space with short focal length optics so space charge doesn't blow up beams, and time bunching for the same reason. The luminosity only has to be high right at the collision point in space-time. Elsewhere, you let the beam spread out or you can't control it anyway. Despite my initials, I don't think a DC fusor will ever fly.

By the way, if you compute the sizes of things, shooting say protons at say a Li target, you are shooting at golf balls 1/3 mile apart from an airplane, with a shotgun -- most of your bullets miss.
However, I actually own guns that can be that accurate easily (I hold some decent all time records doing that), even with wind blowing, barrel vibrations, ammo that is not perfectly all the same and so on. So theoretically one should actually be able to do it better in this case -- atoms are all alike (if it's all the same type of atom) and a cold crystal target, once you know where 3 are, you know where they all are over some range of distance before inevitable motions spoil the coherence. Think of using something similar to an old CRT shadowmask, then focusing an image of that down onto the target -- you do direction selection only on ions going the right way already, and only accelerate (eg invest big energy in) ones that might hit something, rather than wasting all that "powder and lead" with a shotgun shooting from the sky. When I ran the numbers on that, it looked like it could scale to about 10kw output -- with a lot of if's -- like if you can make the shadow mask and optics accurately enough. That's one heck of a small implied hole size to spacing ratio! But R Crewe in his electron microscope work, actually was able to focus a beam well enough to see uranium atoms on a substrate as fuzzy balls -- you aim for the center. Protons or deuterons should be easier to focus better (shorter wavelength).
Too bad he did this fine work just before the scanning tunneling microscope came along and stole his thunder, but I have his papers.

My thinking (and also Curtis Faith, who you should have join your board, he's doing a maybe-credible TOE right now) is that there just has to be some difference in reaction/tunneling rates depending on the relative orientation of the nuclei when they get close -- for example, if it was already closely aligned to the the way He would look, the favored reaction would be to go to He, perhaps, and one sort or another of the other orientations would favor one of the other more common reactions, just as a minimum-effort type of thing -- it will do what's easier to do. In other words, if one of the nuclei had to make a 180 degree flip or spin the other way, it won't do that -- it will do one of the reactions where that doesn't matter instead of the one I want.

And of course, I personally am into the idea of getting useful energy out, and not so much neutrons...which gives me two out of 3 shots in the case of DD.
Obviously, there is something going on in the DT reaction that makes it "can't miss" compared to this, which might be a clue of some sort.

Could be they're going to always hit neutrons-first, though, due to Coulomb forces as they approach....those get real strong in proximity to the event. Curtis thinks we might be able to manage rotations to get them to glance this way or that anyway, I don't have the math for that or for the wave functions rolling off the tip of my tongue though. I doubt anyone here does.

And you're not wasting my time to any greater extent than it is already. I've been reading your board too, and instigating a little over there. Let me know if it's too much...
You think that Martin Braun guy is any good? He sure is a teaser and we've had bad luck with those here and elsewhere sometimes -- they always claim to know everything, but never come out with it, and they really do waste time. He's easy to get going, for sure! Email me if you want. I'm trying to get with that paper over there that talks about energy equivalence and see if I can figure out what he's getting at. I've often wondered about the kind of thing where possibly a De Broglie and a Schrödinger wave set might resonate together between two entities....which would have applicability here to cross sections and how to manipulate them.

As far as I know, that's a completely un looked at field -- things that affect cross sections. We just measure them. It seems we have enough theory, if really worked out, already, to look at that, but no one does it who can. Low hanging fruit? Hope springs eternal!

[Farsight]

A-thermal sounds good Doug. The thing that the public don't seem to appreciate is that when it comes to particle physics, hot is fast moving. A proton doesn't have any property of temperature. Re the crystal, to improve your chances you don't shoot from exactly face-on. Take a step to the side and kneel down, and shoot into a long crystal. You're seeing more nodes, this kind of thing:

.oO.oO.oO
.oO.oO.oO
.oO.oO.oO

...Think of using something similar to an old CRT shadowmask, then focusing an image of that down onto the target -- you do direction selection only on ions going the right way already, and only accelerate (eg invest big energy in) ones that might hit something, rather than wasting all that "powder and lead" with a shotgun shooting from the sky. When I ran the numbers on that, it looked like it could scale to about 10kw output -- with a lot of if's -- like if you can make the shadow mask and optics accurately enough. That's one heck of a small implied hole size to spacing ratio! But R Crewe in his electron microscope work, actually was able to focus a beam well enough to see uranium atoms on a substrate as fuzzy balls -- you aim for the center. Protons or deuterons should be easier to focus better (shorter wavelength). Too bad he did this fine work just before the scanning tunneling microscope came along and stole his thunder, but I have his papers.

Sounds interesting. Anything that ups the odds in your favour is worth looking at.

My thinking (and also Curtis Faith, who you should have join your board, he's doing a maybe-credible TOE right now) is that there just has to be some difference in reaction/tunneling rates depending on the relative orientation of the nuclei when they get close -- for example, if it was already closely aligned to the the way He would look, the favored reaction would be to go to He, perhaps, and one sort or another of the other orientations would favor one of the other more common reactions, just as a minimum-effort type of thing -- it will do what's easier to do. In other words, if one of the nuclei had to make a 180 degree flip or spin the other way, it won't do that -- it will do one of the reactions where that doesn't matter instead of the one I want.

I had a look for Curtis Faith and saw this: http://www.fusor.net/board/view.php?bn= ... 1243479106. Sounds like he's thinking for himself, which is good. See http://lenr-canr.org/acrobat/Meulenbergtunnelingb.pdf re DD reaction paths.

Could be they're going to always hit neutrons-first, though, due to Coulomb forces as they approach....those get real strong in proximity to the event. Curtis thinks we might be able to manage rotations to get them to glance this way or that anyway, I don't have the math for that or for the wave functions rolling off the tip of my tongue though. I doubt anyone here does.

I don't think it's maths that you need here, so much as an understanding of what protons and neutrons actually are.

You think that Martin Braun guy is any good? He sure is a teaser and we've had bad luck with those here and elsewhere sometimes -- they always claim to know everything, but never come out with it, and they really do waste time. He's easy to get going, for sure! Email me if you want.

I'll have a look. I can only hope that everybody remains civil and stays on topic, but hey, people are people.

I'm trying to get with that paper over there that talks about energy equivalence and see if I can figure out what he's getting at.

Don't underestimate it.

I've often wondered about the kind of thing where possibly a De Broglie and a Schrödinger wave set might resonate together between two entities....which would have applicability here to cross sections and how to manipulate them.

There aren't really two types of wave.

As far as I know, that's a completely un looked at field -- things that affect cross sections. We just measure them. It seems we have enough theory, if really worked out, already, to look at that, but no one does it who can. Low hanging fruit? Hope springs eternal!

It's lying on the ground.