Reply To: Great News!
The Focus Fusion Society › Forums › Lawrenceville Plasma Physics Experiment (LPPX) › Steps towards FF-1 Feasibility › Reply To: Great News!
asymmetric_implosionjimmarsen 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.