by Doug Coulter » Sun Nov 02, 2014 12:50 pm
Well, a few of us have indeed read all Farnsworths (and a few others) patents and found them to be both inspiring, and wanting, much like patents of today that people fight over in court. Further, in Farnsworth's case, there was quite a bit of unpublished work that is covered in the Miley book - and some of it made more sense (I have no idea if Miley was selective. but most are).
Re the flipped polarity thing. Carl Willis on fusor.net and others have used that construct with an axial H field for an ion source, and we here thought hard about making an inside-out fusion device, which with the polarity flip, would simply be a glorified beam on target device with the walls serving as a target. Has some interesting advantages there, since it's easier to cool the larger walls vs a small target, which allows them to retain more D as a target, but there's only one of me at present building fusors, and that idea had to take a number, since even in theory - beam on target is more lossy than beam on beam. There has never been a lack of enough high voltage in any serious fusion experiment, it's not the point. If you have to put in say, megavolts, but only get megavolts out - what's the point? No gain.
"Spherical wave guide" is an oxymoron. A wave guide, or for that matter, a piece of coax, is simply a way to move RF from place to place - there are at the least one input and one output. A spherical metal shell IS a resonator for EM fields, but a quick calculation, along with knowing the particle speeds, shows that it's all the very most wrong frequency to do anything much, and that stainless steel has so much skin resistance that even if the plasma was non conductive, there'd be ridiculously low Q. Measuring particle transit times in my fusor has shown they are going a LOT slower, than say, the applied 50kv would indicate, for a variety of reasons that are obvious once you've seen some data on a real machine, or just thought about it enough. It's a lossy media to say the least.
We've worked with a few different cathode materials, as well as a few shell coatings. We find a small amount of secondary electron emission to be good, a lot is bad. I use carbon for the ends (a very low emission coefficient) and right now, tungsten for the grid/lens rods. We also tried thoriated and otherwise doped tungsten that has higher electron emission, and it didn't work as well, since they are emitted at about the worst possible place, and most simply fly to the tank walls and generate waste heat. You need a few, and it seems a few more than the free ones you get from ionizing a neutral gas, but not many.
We don't notice a lot of X rays from electrons just voluntarily trying to hit something fantastically electrically charged to repel them. We do see them from the walls, and using a high Z coating for the walls makes it far worse.
The tank (anode) of course is at ground, mostly for safety of the operator (and the pumps and other plumbing). This has absolutely nothing to do with heat generation. As mentioned above, the fast electrons bashing the anode heat it up just fine, it's a major problem to keep it cool if you want to keep any D embedded in it.
FWIW, the answer to "has this been covered" and much of it has - is called the search function of this board. You might want to view some actual experimental results before talking about theory that doesn't hold in the light of actual observations. You might even then know we don't do spherical fusors here at all, but cylindrical ones (well, kind of) in the 6x6" sidearm of a much larger tank, and that we've set all records of late, blowing the sphere guys off due to the fact we can make an accurate cylindrical lens (line focus, no limit on length) vs a sphere which cannot be tiled with any shape that leads to a good focus in the center and is limited at best to one point.
I'd suggest that in a mixed charge and mass situation people revisit Newtonian mechanics before talking virtual cathodes. It's ridiculous on the face of it - the light, negatively charged electrons that would make one up, repel one another out of the position you'd want, and fly towards the attracitve positive ions - there's this small matter of an 1836*2 difference in mass involved. Which moves more, the lighter or the heavier, given equal forces. We've probed and looked - sorry, the BS from the armchair guys is simply wrong.
FWIW, we've also measured zero confinement, and darned little (fraction of a percent) recirculation. Did I say the all-important word MEASURED? Talk is cheap. There are plenty of sites for that. We're not one of them. We do things here, then report on the actual results. Speculation is only favored when we are trying to explain how a measured result occurred. And at that point, if the experiment was well setup and designed, it usually takes very little to see how it all fits into established science and models in hindsight.
We are NOT trying to simply duplicate Farnsworth, Hirsch, Meeks, or anyone. We're trying to make this work, they failed at that. I have to compliment them for being honest. They saw the odd outlier and super high output but reported it as such as they lacked the data acquisition to know the exact circumstances to replicate it - so they called it an oddity. We don't have that limitation here, and can now say they were being honest - there really are some interesting modes that put out lots more than usual, and now we know how to replicate them at will. That's science -if you can't replicate it, it's junk. If all you do is talk, that's worth even less.
QM doesn't really get involved in what we do till the nuclei are within around a femtometer. We can't of course manipulate any force other than EM, so all we're really doing is setting up the conditions where those super short range forces can take over.
IEC is an utter misnomer, FWIW. There is no confinement at all going on (well, the tank walls keep the shop air out), it's a beam collider, and nearly all the involved particles are once through and out.
We have a recursive system here that makes the Mandebrot set look simple. Math has gone from being the queen of science to at most, the barmaid. There are no solutoins to even the three body gravitational problem (other than perturbation which has its own limits that are shockingly severe). We have a far more complex system here, with perhaps 1017 particles, various charge mass ratios and polarities...there is simply no hope of simulating this before the heat death of the universe with math we have and any computer that will be built before then.
Get thee to a lab boy, and learn some things. Idle speculation is a simple waste of time that could be more profitably used doing a real experiment and measuring something that hasn't yet been. And know some EE and regular science first, don't go straight to QM which, while critical, is all so short range we're not working with that directly, only trying to improve some probabilities things will be close enough for it to take over. Just at the guys who build fission reactors don't control the weak force or the strong whatsoever. They just pile up the right stuff in the right arrangement and let nature take its course. So do we, though there is more detail and precision involved to get two of our projectiles to hit as unlike with uncharged neutrons, we only get pretty much one shot per input acceleration. We hope to improve the reaction rate at the "focus" via better luminosity there, due to focus and bunching. We'd like to pay attention to the well-established conservation laws along the way, as failing to do so doesn't work out well.
Some books, also mentioned elsewhere on the board that might help you get up to speed if you're neither too lazy or too cheap:
Radio Engineers' Handbook by Frederick Emmons Terman, 1943 first edition - out of print but often available at Amazon or used book stores. Covers pretty much all of EE, including calx for resonators and waveguides, as well as the best work on electron optics I've managed to find - and charged particles are charged particles, given a E/M fudge factor for a particular one.
Inertial Electrostatic Confinement by George H. Miley and S. Krupakar Murali - ISBN 978-1-4614-9337-2 Name should be obvious. It would be better if they gave data under more realistic conditions. Somehow they manage to skip over the entire operating regime fusors tend to run in....Some good info on older ideas of Farnsworth and some new speculations, a little math that might reasonably be extrapolated if you take a lot of things they don't bother with into account (at low volts and high pressure, things are just different in odd ways, like scattering).
Quadrupole Mass Spectrometry edited by Peter Dawson ISBN 1-56396-455-4 Pretty good basics on how charged particles act in DC and RF fields, and a really good introduction/visualization of the Mathieu equation - which is what we are working with, only we add a couple of variables to even that hairy stuff (space charge for example).
No one really has "the book" which is what we are writing here - and which is why random speculation is discouraged. It ruins and dilutes the real facts of actual observations made by members here. This is a learning resource, not facebook or G+. Gabbing, we have another forum for, called the water cooler that gets auto-erased unless one of the mods makes a topic sticky. Those are really distinct parts of this place, and the book section (the rest) is why we get so many hits from the search engine bots. Once they can't find something on wikipedia, they come here. When you post, try and keep that in mind. You should also hit the "introduce yourself" thread so people know who they are talking to, and don't go over or under your head too badly.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.