by Doug Coulter » Tue Nov 09, 2010 9:35 pm
(Joe, I have most of the same issues with it -- but yes, you can bend *slow* ions easy without much of a magnet, of the members here who are actual beamline experts, only JohnF has been tickled into posting so far -- and see pix of his lab for the magnets it takes to bend fast ions...not tiny ones.)
Ok, so if you have fields the right magnitudes and all (which I'd have to work out but something smells rotten here...) AND you had more than one bunch going, so (at least) two bunches could pass through the center at a time doing this trick -- assuming near 180 degree, OK, some would hit. The instant they are out of the field, space charge causes each bunch to blow up unless they are going so fast they just don't have time to defocus much due to that.
Also, unless you're going really fast, they never meet in the middle -- the huge charges needed to have any luminosity take a lot of input energy to make it to collision, rather than just spray out randomly before they get close enough -- one of the reasons you don't see fusors running on 5kv. But the approach doesn't work unless the ions are going slow enough that the field can bend them that sharply toward the center on the way out of the outer ring. I'd have to look at the focusing, but it looks to me like the field that would tend to plane focus them on the way "in" from the ring, would then defocus them coming back, for starters.
Also, isn't the center electrode kind of in the way here? Oh I see now -- cute trick. But all this is so poorly written and hard to get through, doesn't look like it's worth it to even take it any farther. The fact that like most bogus patents he's adding things on how to collect the energy he hasn't manage to make and obviously hasn't run the numbers on tells me a lot. Yeah, 6Li will give off some more energy if a slow neutron hits it (uranium might be a better multiplier,,,,duh) but thinking that enough of the neutrons can be slowed and intercepted that way as to think you're going to get in the range of 1::1 captures per neutron produced -- priceless ignorance. An open message to everyone (not just here) -- if you get gain, just call the power plant guys and have them do the rest. It's a done deal at decent efficiency. Just tell 'em you got this thing that stays yellow hot no matter how you try to cool it, and you'll get a knock on the door! If you need a phone number, I have a few of those. Lerner and his un-makeable energy capture scheme comes to mind. Patent away Eric, no one will ever need or want that silly crap even if you could make it.
I'll give up on winning the meaningless points. If nothing came of this since '89 we already have an (non) existence proof -- it doesn't work, and the patent's expired too -- so free for anyone to play with as well, so if anyone else thought it could work, they'd be doing it. I'd rather get Chris' thing up here someplace and not waste time on this. Unless he's changed it a lot it looked to me like it could work (only had semi-minor engineering issues mainly), and that makes me wonder why he's being so reluctant to expose it to those who could tell the difference and maybe even contribute to some success.
Wouldn't it be a lot easier to just make two cyclotrons inside the same H field such that the beams in them would rub like gear teeth of two gears turning the same direction would at their edges? Or three? All you'd need is more appropriately shaped "dee" sections in there and the right RF drives. Or just two intersecting beam storage devices...with the usual re-bunching and re-focusing fields to recover most of the ones that merely scattered a little bit? Of course, the closer you get to collision, the bigger the scatter angles, and no scheme handles that one well.
That is what got me interested in the cone trap beam-ring papers -- being pure electrostatic, one could have counter-rotating beams in one of them, and by adding the usual re-bunching and re accelerating cavities to the stuff in the papers, along with whatever refocusing quads needed -- you're there. Heck, I even bought the toolage to make those and got going, but I'm doing so much better on the fusor with every new thing I try these days, it's beginning to convince me it's not quite the dead end most think of it as. In other words, not an utter waste of time, just a waste of time re getting to gain that way alone. As a super improved neutron source, maybe not a waste of time at all, it's getting so fierce that way we are running less and shorter runs for our own safety. Doesn't take that many microwatt-hours of fusion to make the whole lab start being radioactive -- and my kitchen isn't that far away.
The real limit to colliding beams is (the lack of) space-time bunching, and the fact that you can't maintain either at high luminosities for long times or distances without space charge blowing it all apart. (see klystron or TWT design -- same problems) So you need very short focal lengths and decent energies to get momentary luminosity right at the interaction, but diffuse elsewhere so it's controllable at all. Which is why so far beam on target devices that even give up the nice center mass conservation law still beat fusors by a fat margin -- at least, the target is dense and harder to miss entirely than a particle in a diffuse beam. And that's without smart target tech, which I'm working on as a side issue; for the moment, if it looks like paying off, it will be the main issue very quick -- the advantage of being the owner of one's own lab is being able to follow your nose and no BS from bean counters, managers, and office politics.
There is a reason they need to use 30kv in a CRT TV to put maybe 10-40 watts on screen phosphor (a ma or so) in small dots (good focus, but still the beam is nearly all empty space at that current density -- a few fruit flies in the cathedral) with a decently long focal length with mere electrons, which have sqrt mass ratio issues at the same energies (voltages) compared to ions, here. The factor in this case is about 60 for D -- eg for the same space charge defocus effects, the ions need to have 60x the energy for the same current and FL to have the same beam-spread due to self repulsion...and that would be at the same luminosity as the E beam in a CRT -- low, no where near even the density of a gas, much less a solid. Fairly depressing when you run the numbers.
This is very much born out by my data here, where as I reduce the gas pressures and current, I get both more fusion and more Q along with better visual focus. Reduced scattering off orphan neutrals doesn't explain all of that, though it can't be hurting. I'm still working up enough data to make pretty parametric plots in post-able form, but my notes tell all. Trouble is, down there, the thing isn't self ionizing, so you have to provide the ions with another setup, and with the plain DC fusor, recirculation is actually pretty much nil. Which is why I put up that two grid approach, one an ion trap to gather and bunch ions, then fire them all at once through the center to be recovered after the firing for another try -- driven, not depending on luck or magic.
Until I did the low pressure/current thing, the differences between sloppy made and designed grids and accurate ones that could make a good focus didn't show up -- other things made more difference. Now, that has become important.
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.