Despite the fusor's apparent simplicity I am ignorant of a lot of its issues. Could someone recommend a good book on the topic of fusor theory?
Now the question of the day I have is ion recirculation. When an ion collides with the inner grid it deionizes right? Would the now deionized atom be still attracted to the cathode? How does it get reionized? Or does it?
When an ion collides with a physical cathode, or ground for that matter, it does three things. It looses it's kinetic energy for the most part. This ends up as heat in the wire. This is what makes the wire red hot. Secondly it sucks an electron from the negatively charged wire and becomes neutral. Now it is essentially the same as the very many other neutral atoms/ molecules in the fusor. Third, because of it's KE it sputters off wire molecules/ atoms, which join the gas in the fusor. The electrode can actually be eaten away from this- like sand blasting. This process is actually used in vacuum deposition or sputtering processes for coating things like mirrors and various products.
There is no recycling of these impact ions from an energy perspective. The now neutral ion can be reionized, but it is new energy that does it, the KE of the ion is all (or mostly) lost in heating and sputtering the wire electrode.
Ions can also recombine with free electrons in the plasma, or charge exchange with a neutral atom in the plasma. This complicates trying to keep the ion population hot . If an ion collides with a neutral, it can transfer energy to the neutral, which is then free to fly to the shell, where the KE is lost and heats the Fusor Vacuum vessel shell. There are a lot of things that robs energy from the ions, not to mention the electrons. In a glow discharge fusor operating at ~ 1/100,000 th of an atmosphere or more, most of the 'plasma' is actually neutral gas molecules. Only a small portion of the gas is actuallt ionized at any given time. This has consequences in various ways. In the Polywell, this unhelpful, or actually harmful condition is avoided by operating the general background vacuum level at lower densities- fewer neutrals around. Any ions then created or introduced are concentrated within the Wiffleball. With the ratio of ions to neutrals turned on its head, the beam- background collision problems are greatly (?) reduced. Beam - background = hot ion- cold neutral collisions.
