choff wrote:As I recall from reading up on IEC machines around 07, there was a statement that for a gridded machine to achieve breakeven would require a 10 meter radius, and the grid would have to be transparent. You would think that a wiffle ball effect would make for some improvement.
IF a transparent gridded fusor could achieve breateven, my recolection is that the size would be more in the range of 100-1000 meters radius. The scaling would be r^3/r^2, compared to the Polywellls B^4 *r^3/ r^2 * B^0.25
An example- Fusor at a Q of 0.000000001 at r=1. If grid transparency could be improved to the level of the Polywell ( ~ 1/20 to ~1/ 20,000) the Q would be ~ 0.000001. At r^3/r^2 scaling, breakeven would be at ~ 1,000,000 ^3 / 1,000,000 ^2= 1,000,000 improvement in Q or Q ~=1. Assume the fusor radius starts at 10 cm. This multiplied by 1,000,000 = a radius of ~10,000,000 cm or 100,000 meters.
So your numbers may have been reasonable, but the units is in KM, not meters.
Actually the Fusor would probably never reach breakeven because of upscattering of ions and charge exchange with neutrals (neutrals gain KE but are not effected by the potential well so they are a large loss mechanism). An ion gun fed fusor with vacuum levels several orders of magnitude lower may have much less neutrals mediated losses, but the comparable density drop also significantly decreases the fusion rate. The only work around may be very high confluence (central focus) but this is limited by the virtual anode that would form.
This illustrates the supreme importance of the Wiffleball effect. With the ~ 1000 or greater fold increase in workable densities, the fusion rate goes up by at least a million per unit of volume.
Dan Tibbets
To error is human... and I'm very human.
