FF-1 has taken a long step toward demonstrating the level of repeatable firing needed for a fusion generator. On November 2, FF-1 fired five shots in a row, under the same conditions, with fusion yield varying by only plus or minus 2.6% from an average of 0.9×1011 neutrons. While dense plasma focus (DPF) devices preceding FF-1 have had a reputation for large shot-to-shot variability, a fusion generator (as well as most other applications) requires repeatable functioning. In May 2011, LPP reported that our research team had succeeded in stabilizing FF-1’s output to within a range of plus or minus 15%. The latest, tighter stability of function represents a six-fold improvement over the May results and achieves approximately the range of reliability that would be required in a generator pulsing many times per second.
The greater repeatability, we believe, is due to our tighter control of asymmetries in the device, including the centering of the electrodes
Latest FF-1 tweaking aims to eliminate small tilts
In LPP’s continuing effort to improve the symmetry of FF-1’s electrodes, we made modifications to the central o-ring and insulating Mylar sheets to eliminate a small tilt we had detected in the alignment of the electrodes. The alignment of the electrodes is critical in producing a symmetric current sheath, which in turn is needed to get the highest compression of the plasmoid where the fusion reactions occur. There is only a 15 mil (thousandths of an inch) clearance between the insulator and the cathode, or outer electrode, so this distance must be kept constant to within one mil around the whole circumference of the insulator. While previous efforts have accurately centered the insulator at its base, any slight tilt in the large steel plate holding the anode can create a misalignment when the insulator passes close to the cathode.