Numerical simulation of mather, filippov and concentric plasma focus using Lee model

Abstract

In this study, numerical simulations of concentric, Mather and Filippov dense plasma focus (DPF) devices using Lee Model have been performed to test the universality of Lee Model. It includes the configuring of the Lee Model Code to work as any DPF devices from measured current waveform to modelling for diagnostics, evolution of the diagnostics-time histories for the dynamics, energies and plasma properties computed from the measured total current waveform by the code. DPF is a potential source of neutrons. The current research focus is on computing the neutron yield,Yn, from DPF by numerical experiments. Published experimental results from these DPF are then compared and analyzed with numerical simulations results in terms of Yn at different operational parameters. The numerical simulations were executed using the 5-phase Lee Model Code version RADPFV5.15de. The computed Yn from a concentric deuterium-tritium KPU-200 DPF is 1.44 X 1013 neutrons per shot at pressure 14.25 Torr and charging voltage 47.7 kV. For the 1.4 kJ DPF, the optimum, Yn was 2.9 X 107 neutrons/shot at 5.5 Torr deuterium pressure. The optimum computed Yn for 11.2 kJDPF at 4.1 Torr was 1.447 X 10s neutrons/shot. For 28.8 kJ device, the optimum computed Yn of 1.24 X 109neutrons/shot was obtained at 2.2 Torr deuterium pressure at 20 kV. For the 480 kJ device, the optimum yield of 1.8 X 1011 neutrons/shot was obtained at pressure 7.6 Torr and charging voltage of 27 kV. Analysis of the results shows that the optimum Yn was achieved only at optimum operating conditions. For the Dena Filippov DPF with discharge energies of 5 kJ and 90 kJ at pressures ranging from 0.1 Torr to 2.5 Torr, the computed Yn is 1.5 X 109 neutrons/shot in agreement with the experimental result of 1.2 X 109 neutrons/shot using deuterium gas. The computed Yn of Iranian First Filippov Type Plasma Focus (IFFT-PF) with deuterium as working gas at pressure of 0.6 Torr is 3.4 X 106 neutrons/shot as compared to the published value o f 3 . 1 x l 0 6 neutrons/shot. These results show that the computed Yn is in good agreement with the measured Yn at charging voltage of 16 kV for Dena device and 26 kV for IFFT-PF. The modelling, results and applications of the Lee Model code are of profound interest.