Reply To: Great News!

[Joeviocoe]

asymmetric_implosion wrote:

Does the physics of DPF prevent designing a larger device; are there engineering limitations?

Yes and no. The primary limitation encountered to date is the insulator between the anode and cathode in vacuum. Experiments have demonstrated a system without an insulator at 5 MA but the experiments were focused on soft x-ray production. Is the insulator the show stopper to scale up??? I don’t know for sure. Some experiments at 2 MA suggest a solution to the problem but it might drive the fusion yield away from optimum. This is a pressing point in PF physics that is actively researched because scaling up a PF to high current should cost less than a Z-pinch. The problem to date is that PF devices seem to show decreased fusion yield with currents above 1 MA. Z-pinch devices show a fall off at something like 300 kA. See the attached figure with PF devices and radial implosion Z-pinch devices as an example. This is data I’ve compiled from the 1970’s to present from peer-reviewed published lit including data from LPP. If you can scale up the device along the alpha=0.25 curve, you can get more fusion yield per shot. If the fusion yield (DD neutron yield) falls off at 2 MA or more, it seems that a smaller and high rep rate PF is the better option.

I thought that it was higher voltages that brokedown the insulator, not higher current. And that higher current, with higher cycle rates, causes the skin effect to heat the cathode unevenly causing damage.

And that the DPF fusion yields scale higher with increased current ( I^4.7 ) but that 3 MA would be optimal.

Am I completely wrong here?