Contamination of the plasma has been a problem in DPF devices as shown by LPPFusion’s latest report. I propose a hybrid solution to reduce the contamination. It may have some weaknesses but could spark an interesting discussion.
Mass spectrometry and calutron machines can separate heavy contaminant ions from the lighter fuel ions. They may process the fuel too slowly to be practical for a dpf. If you look at a seperator schematic it has three basic parts: an ion source, a magnet and a collector. I suggest using a plasma railgun as the ion source using the fusion fuel, a magnet and the collector is the back end of a dpf device. Some type of plasma wave shaping system would have to create a smooth wave front as the plasma enters the dpf. The plasma wave would contact the high voltage high current electrodes and form the plasma sheath as normal. The rest of the operation proceeds as usual in the dpf.
I see two advantages if this system works. First, the fuel should be cleaner entering the dpf and the plasma wave front should be moving too fast for the heavy ions from the electrodes to catch up. Second, the plasma wave is already moving at a high speed so the capacitor bank doesn’t have to use so much energy accelerating the plasma which leaves more energy for the pinch phase.