Postby D Tibbets » Mon May 21, 2012 10:14 pm
I still do not appreciate your terminology. The 'electron ball' is an accelerator, for the ions introduced at the edge, once inside the electron ball has little effect on the ions (with some adjustments depending on the shape of the potential well). The ions that have been accelerated towards the center in isolation (non collisional plasma)to form a tiny condensed core- point like volume, works, but with useful numbers of ions (collisional plasma) a vertual anode forms and this acts as a decelerator or diverter that prevents a point (event horizon?) limits the size of the core to larger volumes. If the ions converged (were focused) to a tiny , almost point like volume in the center (or anywhere else for that matter) the density of positive chagred ions would be so great that virtual anode would not be 15-20% of the potential well, but very much greater than the potential well. This would destroy the potential well very quickly.The 2008 patent application did mention a ' black hole' like effect where the ions condensed to such a tiny volume that the ions would have a zero chance of escaping before fusion. This was a speculative assertion though with the recognition that reaching such conditions was impossible, at least without accelerating the ions to many millions of eV which would cost to much energy and would open up another new set of problems (like photodisentigration). A pulsating inertial confinement machine might do this but only for very brief period of time. Things like two stream instability ,etc. precludes this working profitably except in those machines where the inertia of the ions and very high densities are the dominating considerations (ie: a bomb). Polywell is a steady state machine, so that the density, temperature and confinement time working together allows for the claimed positive Qs. What you are conceiving may be more like inertial confinement fusion. These can only operate for short time intervals like bombs, or laser inertial confinement fusion. While not impossible, the difficulty and cost of this approach is represented by the National Ignition Facility, and perhaps Dense Plasma Focus (opposite ends of the scale). The idea is that the much higher densities compensate for the much lower confinement time. Also,the polywell may actually work with almost no confluence of the ions. This is similar to the Tokamak, except the increased density again makes up for the shorter confinement times. Again the triple product consideration.
As for a focus of ions outside the Wiffleball I don't think this is possible with a quasi spherical machine. A cylindrical device could certainly accelerate ions, but not have a central focus. This would be equivalent to a Polywell with out any convergence. A Tokamak would fit this description. The difference is that the Pollywell can reach densities ~100-1000 times greater, and this directly determines the necessary confinement time needed for adequate fusions to occur. The triple product consideration is critical, and all fusion approaches uses tradeoffs to attempt to achieve this balance without expending too much energy. A Beam- Beam approach does not work, because a dense enough focus cannot be achieved without expending too much energy. The Polywell may operate in a similar manner, except it cheats. If the ions do not fuse they scatter outward in a spherical fashion from near the center and are recycled for thousands of additional attempts, and importantly do this without needing much additional energy input. If this could be done in a cylindrical fashion the multipass confluence would not be as great as the center is defined as a line along the cylinder instead of a point (spherical volume) in the center of a sphere. The density gains are less.
As for injection of electrons or ions from external guns, they have to be aligned well with the cusp axis or more of the charged particles will be mirrored back without entering the machine. This costs more and may limit the internal densities obtained compared to the external densities- which is a limiting factor.
There are other considerations that apply, but basically the Polywell traps ions at higher density (whether there is convergence or not) than Tokamaks can, and through clever tricks do so so at acceptable costs. This results in useful fusion rates at much smaller machine costs and size.
Assuming all the various approaches work, I wonder if the Polywell will be a more condensed power producer than say a DPF. The latter may have the advantage if only a few MW is needed as one machine could produce this. But for a few hundred MW, a single Polywell may suffice, while perhaps ~one hundred DPF machines would be required. Compared to Tokamaks this consideration may not apply as Polywells can be scaled up quickly, while DPF cannot. And the baseline Tokamak is already too large for typical grid applications.
Dan Tibbets
To error is human... and I'm very human.
hmmm
