Migma

[Doug Coulter]

Well, here's an off the wall one, have some fun finding the "then a miracle occurs" issue with it, I'll keep my answer for later...
As usual, click the image for a larger version you can actually do something with.

From JSTOR

From JSTOR

Spoiler:
How does the radius of curvature change to a smaller one to get those figure 8's? Is a left-out detail that the H field isn't uniform, do they lose energy some other way? If they lose energy, do they continue to do so forever? Do the helicies in the vertical oscillations (which look just like what a uniform field cyclotron undergoes) make everything miss at the interaction points?

Any thoughts?

[johnf]

Curios
the physics seems a bit bent on the additiion of the electron beam.
yes neutralising the charge after acceleration would stop the repulsion. normally this is done with the electron beam being at right angles to the charged particle beam. i use this in our sputter system for non conductive targets so the target does not charge up and deflect the argon beam away from the target.

As for the figure eights are the ions giving up energy to the plates hence a slow down and a tightening of radius--I will to give this more thought

[Doug Coulter]

Well, for whatever reason, the story is the inventor got into an acrimonious battle with his source of funding - after setting what was then a record. Whether he was a jerk, or there's something important (scientific) missing, dunno - not a clue.
If electrons hang around, they are a great way to lose all your input energy into photons....
At this point, I'm pretty sure we don't even know what's going which way in a fusor, and how much, just total current flow. For example, are those negative (I think) things coming out the end of the grid electrons, D-, what? Not a hint yet.
Likely electrons, but...there's that evidence we have of losing Q as the tank walls heat up and discharge whatever D is buried there - so it's not *all* electrons...there's a lot we don't know how or why going on here - and it looks like emergent behaviour that isn't predicted/prescripted by the standard model. That doesn't mean the model won't explain it flawlessly once we know what it is - it's just that you can't get from theory to what we see - we need data on what's actually happening in there.

Understanding an ant doesn't tell you about how an ant colony works, to map the problem onto physics of charged particles. And it for certain doesn't tell you why there are ant colonies and how they fit into the big picture. The math just isn't there yet for things like that. This looks like another "one of those", to me, anyway. I've always been enamored of the idea that you'd do this with precision and subtlety, rather than brute force, since it's becoming obvious that the brute force/obvious approaches don't yield much Q, even after decades and lots of money tossed their way. So something else must be the answer if there is one. Of course, I do hope that there is one, and that one of us finds it.

This particular paper was pointed out to us by an old friend of Bill's, who used to work the field. I'm not sure whether he thought we were trying this, or if he thought we should. Might not be all that hard to try, if I can get more details on what they actually did. That strange curve-change of the trajectory tells me there's something here I don't "get", so far.

[johnf]

Doug

As I have said many times before electrons are a curse when dealing with ions (+) I have no experience with negative ions.
That is why we go to a great deal of trouble to suppress secondary electron production in our implanters. The beasties give fake ion numbers on target and if lucky kill the ions in a way that our focusing is ignored (electrostatic).
Going back to the sputter system I look at the ion current when using an insulating sputter target and adjust the electron flood to bring the ion current to zero on the sputter target. We know that the now neutral atoms arrive by the sputtered atoms on the object de jour measured by RBS ETC.

Exact approximate guesses are used to get the desired result.

[Doug Coulter]

I have to agree - electrons are those things you can't live with, but also can't live without. You kinda need some to make ions (or get some as a result), but you sure don't want to "invest" 99.999xxx percent of your energy into accelerating them, heating the wrong stuff up, making X rays and so forth - as most fusors (including mine most of the time with the current setup) do. Perhaps a little trickery is going to be required, probably with a magnetic field, here. At least we could make them take a much longer path to ground, and perhaps make ions more efficiently in lower pressure gas, which seems to have other attached advantages (fewer collisions and scattering with neutrals, and lower space-charge defocusing being two I know of).