FF-1 Shots Put 12 kJ into Pinch Region, Needs 3D Modeling Help to Go HigherAugust 16, 2016
A new analysis of LPPFusion’s experimental results with the FF-1 device shows that fully 20% of the input energy was concentrated into the pinch region, where fusion reactions occur. As much as 12 kJ out of the capacitor bank’s initial 60 kJ was compressed into the pinch. These results, obtained in June with tungsten electrodes and pre-ionization, are about twice as good as the best ones obtained earlier with copper electrodes. The analysis was based on the device’s measured current and the voltage measured across the electrodes.
The significance of this result is that it implies that with higher current, nearly all the available energy can be transferred to the pinch. The energy available in the pinch is proportional to the square of the current, so with a current of around 2.8 MA, instead of the present 1.1 MA, energy into the pinch could be increased to 80 kJ, which is almost 70% of the maximum energy that can be put into FF-1. While a high efficiency of energy transfer into the pinch does not guarantee net fusion energy output (high density is also required, in addition to the high temperatures FF-1 already achieves), it is necessary for the net fusion goal.
How can FF-1’s current be increased? One step is relatively easy—the LPP Fusion research team can put back into use the full 12 capacitors of the device, up from the presently-used 8 capacitors. (The team has put off doing this for now, because this puts more stress on the components and allows fewer spares). Another step, shortening the electrodes, is already planned. Shorter electrodes have less inductance—a measure of how much magnetic field energy is created for a given amount of current. Less inductance means more current for the same amount of stored energy.
But to get to the full planned current of 2.8 MA, the inductance of other parts of the FF-1 circuit must be reduced, so more energy is available inside the vacuum chamber, and less is wasted in magnetic field energy outside the chamber. The research team has some concrete ideas of how to do this, but we need help in testing them out. LPPFusion needs paid help from someone who has done 3D modeling of pulsed power circuits and has present access to the software required—such as COMSOL. If you have these specialized skills, or know someone who does, please get in touch with us and we can give you more details and solicit a proposal.