Thanks Jones, I did see a diagram of a positive inner grid device on that site you quoted: http://www.fusor.net/files/EMC2_FusionToPost.pdf "So that brings us to Figure 2. The Elmore-Tuck-Watson machine4 is the reverse of a Hirsch Farnsworth machine. The inner grid is positively charged instead of negatively charged, so it attracts electrons instead of ions. Electrons pass thru the inner grid and converge on the center, pass out the other side, then come back for another pass. The result, at sufficiently high current and voltage, is a very dense region of negative charge in the center of the machine. This is really what you want instead of the negatively-charged grid in the Hirsch-Farnsworth machine. If you generate deuterons just inside the inner grid of an Elmore-Tuck-Watson machine, they'll oscillate happily thru that cloud of electrons for a very long time. The electrons and ions are at such high energy that they essentially can't recombine to any significant degree, so, in principle, the ions might make enough passes thru that central region to produce meaningful fusion."
I can't say the explanation makes total sense to me, but I noticed they mention _electrons_ being attracted to that positive inner grid, not D2- ions as you proposed... it is well known that the vast majority of charged particles in D2 glow discharges are electrons and deuterons BTW. I agree a high density of electrons at the center is a good thing as they screen the deuterons from each other, so maybe the screening effect in this positive inner electrode machine is more useful than accelerating the deuterons in the Farnsworth-Hirsch fusor (negative inner electrode)... which must be pushed around by the high energy electrons anyway... can the maths of this be found somewhere? Michel ----- Original Message ----- From: "Jones Beene" <[EMAIL PROTECTED]> To: <vortex-l@eskimo.com> Sent: Friday, May 23, 2008 4:32 PM Subject: Re: [Vo]:Virtual inner electrode Fusor? (was Re: Chlorine photo-reactivity) > --- Michel > >> > Either way will work. > >> Are you sure? A ref to a fusor where the outer >> electrode is the more negative one would be welcome, > > The Hilsch "improvement" to the original idea uses the > negative inner grid. > > Farnworth tried everything else, including an electron > gun(s) outside the chamber, with or without a > dedicated grid, to accelerate the negative charge. > Like Gow at Berkeley, PF at first used a cylinder for > containment, instead of a sphere. > > There was also a 'mini accelerator'. As I understand > the situation, at this range of potential (< 100 keV) > there is a rather substantial advantage in > accelerating negative deuterium molecular ions (D2-) > instead of positive deuterons. Order of magnitude > advantage in current. He is one such reactor: > > http://49chevy.blogs.com/fusor/images/396pxus3386883__fusor.png > > Back to the 'virtual' electrode. As you know, when you > fire an array of electron beams into a plasma, as PF > did on occasion, the electrons do not go very far, so > in effect- THIS can be your virtual electrode, sans > grid (from the perspective of the inner volume. > > The plasma tends to bifurcate in charge, like a > natural capacitor, depending on the polarity of the > outer containment. If your plasma is colder, and the > predominant species is (D2-)then you may want the > structure to be negatively charged (NOT grounded) and > an inner grid positive- to accelerate the ions. > > If you think that arrangement sounds > counter-intuitive, then you are not familiar with the > incredible nuclear reactor design of Kapitza, from the > 60's. > > Kapitza is the famous Russian who also invented the > tokomak. He was able to achieve a virtual charge > separation, and fusion, in a charged *D2 GAS* near one > atm pressure! - no real plasma required ! Yes, this > muddies the definition of "plasma". > > I wish I could find the url quickly for that one, but > it will have to wait unless you have time to look. It > may not be online as it preceded the breakup of the > USSR. > > I have often thought (in a bit of historical > revisionism) that if PF and Kapitza had gotten > together with decent funding in the 60's (impossible > at the time) they could have pushed a hybrid idea for > warm D fusion to breakeven. > > The breakeven would probably be complex, and have to > come from what happened to the neutrons -- after they > left the Fusor, (multiplication via subcritical U > fission) but who cares (nowadays)? > > Jones > >
