Current and neutron scaling for megajoule plasma focus machines

In a 2007 paper Nukulin and Polukhin surmised from electrodynamical considerations that, for megajoule dense plasma focus devices, focus currents and neutron yield Y(n) saturate as the capacitor energy E(0) is increased by increasing the capacitance C(0). In contrast, our numerical experiments show no saturation; both pinch currents and Y(n) continue to rise with C(0) although at a slower rate than at lower energies. The difference in results is explained. The Nukulin and Polukhin assumption that the tube inductance and length are proportional to C(0) is contrary to laboratory as well as numerical experiments. Conditions to achieve Y(n) of 10(13) in a deuterium plasma focus are found from our numerical experiments, at a storage energy of 3MJ with a circuit peak current of 7.6MA and focus pinch current of 2.5MA.