Confined ion energy >200 keV and increased fusion yield in a DPF withmonolithic tungsten electrodes and pre-ionization

To reduce impurities in the dense plasma focus FF-1 device, we used monolithic tungstenelectrodes with pre-ionization. With this new set-up, we demonstrated a three-foldreduction of impurities by mass and a ten-fold reduction by ion number. FF-1 produced a50% increase in fusion yield over our previous copper electrodes, both for a single shotand for a mean of ten consecutive shots with the same conditions. These results representa doubling of fusion yield as compared with any other plasma focus device with the same60 kJ energy input. In addition, FF-1 produced a new single-shot record of 240 ± 20 keVfor mean ion energy, a record for any confined fusion plasma, using any device, and a 50%improvement in ten-shot mean ion energy. With a deuterium-nitrogen mix andcorona-discharge pre-ionization, we were also able to reduce the standard deviation in thefusion yield to about 15%, a four-fold reduction over the copper-electrode results. Weintend to further reduce impurities with new experiments using microwave treatment oftungsten electrodes, followed by the use of beryllium electrodes.