Reply To: I think the biggest transition that will shock the industry will be the need for Desalination Plants.

[asymmetric_implosion]

meemoe_uk wrote: Well here’s an amateur’s rough design. If its no good, you can tell me why and I can learn something!

Are we allowed to move the anode away from the cathode?
– The barriers have orifices to allow fluid circulation.
– The cathode edge ( and ideally its whole cylinder ) is positioned out of direct line from the fusion zone
– If need be, the anode can be simply shielded from direct line of the fusion zone too.

You have designed a Z-pinch. You have lost the axial flow of plasma that stabilizes the plasma focus and allows for reproducible operation. The cathode is a lesser problem than the anode in a plasma focus. The anode takes the brunt of the energy from the expanding pinch plasma. This can lead to metal vaporization, melting, etc, of the electrode. The cathode will vaporize but a much smaller extent as the current is distributed over a larger area.

The proximity of the electrodes is a key problem for any pulse power based approach that directly flows current into the plasma. Tokameks and laser systems remove this complication by taking away electrodes. The move to the tokameks was driven by the electrode problems in long, slow Z-pinches. The materials problem of the PF is non-trivial and needs a serious research effort. A few teams have only scratched the surface and as is usually the case, the answer is not the same for every application. For example, the LPP need for high x-ray transmission of the anode is driving the use of Beryllium. Folks working on neutron generators and lithographic x-ray sources are less concerned about x-ray absorption in the anode and favor long lifetime operation so they choose materials like SS-304, molybdenum and tungsten alloys.

The message at the end of the day is the electrodes are a consumable. You can only extend their life so far given the limits of available materials. The alternative is to choose inexpensive materials that can be replaced rapidly. I favor frequent replacement as complex engineering system may not buy much increase in operational lifetime for a significant cost sink. Another trade study to be completed.